A kinase-regulated PDZ-domain interaction controls endocytic sorting of the beta2-adrenergic receptor.
AuthorsCao TT,Deacon HW,Reczek D,Bretscher A,von Zastrow M
JournalNature
PubMed ID10499588
Caveolin-associated filamentous actin (Cav-actin) defines a novel F-actin structure in adipocytes.
AuthorsKanzaki M, Pessin JE
JournalJ Biol Chem
PubMed ID12039946
Dynamic actin remodeling has been implicated in the translocation of the insulin-responsive glucose transporter 4 (GLUT4) to the plasma membrane in adipocytes. Here we show that fully differentiated 3T3L1 adipocytes have unique cortical filamentous actin structure, designated Cav-actin (caveolae-associated F-actin). During 3T3L1 adipocyte differentiation, rhodamine-phalloidin staining demonstrated the formation of ... More
Actin filament cross-linking by MARCKS: characterization of two actin-binding sites within the phosphorylation site domain.
AuthorsYarmola EG, Edison AS, Lenox RH, Bubb MR
JournalJ Biol Chem
PubMed ID11294839
We recently identified conformational changes that occur upon phosphorylation of myristoylated alanine-rich protein kinase C substrate (MARCKS) that preclude efficient cross-linking of actin filaments (Bubb, M. R., Lenox, R. H., and Edison, A. S. (1999) J. Biol. Chem. 274, 36472-36478). These results implied that the phosphorylation site domain of MARCKS ... More
Assembly of adherens junctions is required for sphingosine 1-phosphate-induced matriptase accumulation and activation at mammary epithelial cell-cell contacts.
AuthorsHung RJ, Hsu IaW, Dreiling JL, Lee MJ, Williams CA, Oberst MD, Dickson RB, Lin CY
JournalAm J Physiol Cell Physiol
PubMed ID15075215
Sphingosine 1-phosphate (S1P), a bioactive phospholipid, simultaneously induces actin cytoskeletal rearrangements and activation of matriptase, a membrane-associated serine protease in human mammary epithelial cells. In this study, we used a monoclonal antibody selective for activated, two-chain matriptase to examine the functional relationship between these two S1P-induced events. Ten minutes after ... More
Differential control of clustering of the sodium channels Na(v)1.2 and Na(v)1.6 at developing CNS nodes of Ranvier.
AuthorsKaplan MR, Cho MH, Ullian EM, Isom LL, Levinson SR, Barres BA
JournalNeuron
PubMed ID11343648
'Na(v)1.6 is the main sodium channel isoform at adult nodes of Ranvier. Here, we show that Na(v)1.2 and its beta2 subunit, but not Na(v)1.6 or beta1, are clustered in developing central nervous system nodes and that clustering of Na(v)1.2 and Na(v)1.6 is differentially controlled. Oligodendrocyte-conditioned medium is sufficient to induce ... More
Modulation of the F-actin cytoskeleton by c-Abl tyrosine kinase in cell spreading and neurite extension.
AuthorsWoodring PJ, Litwack ED, O'Leary DD, Lucero GR, Wang JY, Hunter T
JournalJ Cell Biol
PubMed ID11864995
'The nonreceptor tyrosine kinase encoded by the c-Abl gene has the unique feature of an F-actin binding domain (FABD). Purified c-Abl tyrosine kinase is inhibited by F-actin, and this inhibition can be relieved through mutation of its FABD. The c-Abl kinase is activated by physiological signals that also regulate the ... More
Regulation of melanosome movement in the cell cycle by reversible association with myosin V.
AuthorsRogers SL, Karcher RL, Roland JT, Minin AA, Steffen W, Gelfand VI
JournalJ Cell Biol
PubMed ID10491390
'Previously, we have shown that melanosomes of Xenopus laevis melanophores are transported along both microtubules and actin filaments in a coordinated manner, and that myosin V is bound to purified melanosomes (Rogers, S., and V.I. Gelfand. 1998. Curr. Biol. 8:161-164). In the present study, we have demonstrated that myosin V ... More
Intravital two-photon microscopy for studying the uptake and trafficking of fluorescently conjugated molecules in live rodents.
AuthorsMasedunskas A, Weigert R,
JournalTraffic
PubMed ID18647170
'In this study, we describe an experimental system based on intravital two-photon microscopy for studying endocytosis in live animals. The rodent submandibular glands were chosen as model organs because they can be exposed easily, imaged without compromising their function and, furthermore, they are amenable to pharmacological and genetic manipulations. We ... More
Colocalization and redistribution of dishevelled and actin during Wnt-induced mesenchymal morphogenesis.
AuthorsTorres MA, Nelson WJ
JournalJ Cell Biol
PubMed ID10871283
'Activation of the Wnt signaling pathway is important for induction of gene expression and cell morphogenesis throughout embryonic development. We examined the subcellular localization of dishevelled, the immediate downstream component from the Wnt receptor, in the embryonic mouse kidney. Using immunofluorescence staining, confocal microscopy, and coimmunoprecipitation experiments, we show that ... More
The platelet cytoskeleton regulates the affinity of the integrin alpha(IIb)beta(3) for fibrinogen.
AuthorsBennett JS, Zigmond S, Vilaire G, Cunningham ME, Bednar B
JournalJ Biol Chem
PubMed ID10464255
'Agonist-generated inside-out signals enable the platelet integrin alpha(IIb)beta(3) to bind soluble ligands such as fibrinogen. We found that inhibiting actin polymerization in unstimulated platelets with cytochalasin D or latrunculin A mimics the effects of platelet agonists by inducing fibrinogen binding to alpha(IIb)beta(3). By contrast, stabilizing actin filaments with jasplakinolide prevented ... More
Actin- and protein-4.1-containing filaments link nuclear pore complexes to subnuclear organelles in Xenopus oocyte nuclei.
AuthorsKiseleva E, Drummond SP, Goldberg MW, Rutherford SA, Allen TD, Wilson KL
JournalJ Cell Sci
PubMed ID15128868
'We imaged the interiors of relatively intact Xenopus oocyte nuclei by field emission scanning electron microscopy (feSEM) and visualized a network of filaments that attach to nuclear pore complexes and extend throughout the nucleus. Within the nucleus, these ''pore-linked filaments'' (PLFs) were embedded into spherical structures 100 nm to approximately ... More
Aberrant actin cytoskeleton leads to accelerated proliferation of corneal epithelial cells in mice deficient for destrin (actin depolymerizing factor).
AuthorsIkeda S, Cunningham LA, Boggess D, Hawes N, Hobson CD, Sundberg JP, Naggert JK, Smith RS, Nishina PM
JournalHum Mol Genet
PubMed ID12700171
'Corneal disease is the most common cause of bilateral blindness in the world. Visual loss in this condition is often due to changes in morphology and function of the corneal epithelial surface. Corneal disease-1 (corn1) and corn1(2J) are spontaneous mouse mutants that develop irregular thickening of the corneal epithelium, similar ... More
The cortical localization of the microtubule orientation protein, Kar9p, is dependent upon actin and proteins required for polarization.
AuthorsMiller RK, Matheos D, Rose MD
JournalJ Cell Biol
PubMed ID10085294
'In the yeast Saccharomyces cerevisiae, positioning of the mitotic spindle requires both the cytoplasmic microtubules and actin. Kar9p is a novel cortical protein that is required for the correct position of the mitotic spindle and the orientation of the cytoplasmic microtubules. Green fluorescent protein (GFP)- Kar9p localizes to a single ... More
Regulated exocytosis in neuroendocrine cells: a role for subplasmalemmal Cdc42/N-WASP-induced actin filaments.
AuthorsGasman S, Chasserot-Golaz S, Malacombe M, Way M, Bader MF
JournalMol Biol Cell
PubMed ID14617808
'In neuroendocrine cells, actin reorganization is a prerequisite for regulated exocytosis. Small GTPases, Rho proteins, represent potential candidates coupling actin dynamics to membrane trafficking events. We previously reported that Cdc42 plays an active role in regulated exocytosis in chromaffin cells. The aim of the present work was to dissect the ... More
An epithelial cell destined for apoptosis signals its neighbors to extrude it by an actin- and myosin-dependent mechanism.
AuthorsRosenblatt J, Raff MC, Cramer LP
JournalCurr Biol
PubMed ID11728307
'BACKGROUND: Simple epithelia encase developing embryos and organs. Although these epithelia consist of only one or two layers of cells, they must provide tight barriers for the tissues that they envelop. Apoptosis occurring within these simple epithelia could compromise this barrier. How, then, does an epithelium remove apoptotic cells without ... More
The Abl-related gene (Arg) requires its F-actin-microtubule cross-linking activity to regulate lamellipodial dynamics during fibroblast adhesion.
AuthorsMiller AL, Wang Y, Mooseker MS, Koleske AJ
JournalJ Cell Biol
PubMed ID15138293
'Microtubules (MTs) help establish and maintain cell polarity by promoting actin-dependent membrane protrusion at the leading edge of the cell, but the molecular mechanisms that mediate cross-talk between actin and MTs during this process are unclear. We demonstrate that the Abl-related gene (Arg) nonreceptor tyrosine kinase is required for dynamic ... More
Rho-ROCK signal pathway regulates microtubule-based process formation of cultured podocytes--inhibition of ROCK promoted process elongation.
AuthorsGao SY, Li CY, Chen J, Pan L, Saito S, Terashita T, Saito K, Miyawaki K, Shigemoto K, Mominoki K, Matsuda S, Kobayashi N
JournalNephron Exp Nephrol
PubMed ID15218323
'BACKGROUND: Podocytes, renal glomerular visceral epithelial cells, have two kinds of processes, namely major processes containing microtubules (MTs) and foot processes with actin filaments (AFs). The present study investigated how MTs are organized by the Rho-ROCK signal transduction pathway during process formation of podocytes. METHOD: After induction of differentiation, podocytes ... More
Drs2p-coupled aminophospholipid translocase activity in yeast Golgi membranes and relationship to in vivo function.
AuthorsNatarajan P, Wang J, Hua Z, Graham TR
JournalProc Natl Acad Sci U S A
PubMed ID15249668
'Aminophospholipid translocases (APLTs) are defined primarily by their ability to flip fluorescent or spin-labeled derivatives of phosphatidylserine (PS) and phosphatidylethanolamine (PE) from the external leaflet of a membrane bilayer to the cytosolic leaflet and are thought to establish phospholipid asymmetry in biological membranes. The identities of APLTs remain unknown, although ... More
Association with membrane protrusions makes ErbB2 an internalization-resistant receptor.
AuthorsHommelgaard AM, Lerdrup M, van Deurs B
JournalMol Biol Cell
PubMed ID14742716
'In contrast to the epidermal growth factor (EGF) receptor, ErbB2 is known to remain at the plasma membrane after ligand binding and dimerization. However, why ErbB2 is not efficiently down-regulated has remained elusive. Basically, two possibilities exist: ErbB2 is internalization resistant or it is efficiently recycled after internalization. By a ... More
Actin cytoskeleton is required for nuclear accumulation of Gln3 in response to nitrogen limitation but not rapamycin treatment in Saccharomyces cerevisiae.
AuthorsCox KH, Tate JJ, Cooper TG
JournalJ Biol Chem
PubMed ID14970238
'Saccharomyces cerevisiae selectively utilizes good nitrogen sources in preference to poor ones by down-regulating transcription of genes encoding proteins that transport and degrade poor nitrogen sources when excess nitrogen is available. This regulation is designated nitrogen catabolite repression (NCR). When cells are transferred from a good to a poor nitrogen ... More
Insulin action on GLUT4 traffic visualized in single 3T3-l1 adipocytes by using ultra-fast microscopy.
AuthorsPatki V, Buxton J, Chawla A, Lifshitz L, Fogarty K, Carrington W, Tuft R, Corvera S
JournalMol Biol Cell
PubMed ID11160828
'A novel imaging technology, high-speed microscopy, has been used to visualize the process of GLUT4 translocation in response to insulin in single 3T3-L1 adipocytes. A key advantage of this technology is that it requires extremely low light exposure times, allowing the quasi-continuous capture of information over 20-30 min without photobleaching ... More
BDNF induces translocation of initiation factor 4E to mRNA granules: evidence for a role of synaptic microfilaments and integrins.
AuthorsSmart FM, Edelman GM, Vanderklish PW
JournalProc Natl Acad Sci U S A
PubMed ID14623964
'In many cell types, translation can be regulated by a redistribution of translation initiation factors to actin-based cytoskeletal compartments that contain bound mRNAs. This process is evoked by extracellular signals and is regulated by determinants of cytoskeletal organization, such as integrins. In the present experiments, we provide evidence that similar ... More
Activation of proteinase-activated receptor-2 in mesothelial cells induces pleural inflammation.
AuthorsLee YC, Knight DA, Lane KB, Cheng DS, Koay MA, Teixeira LR, Nesbitt JC, Chambers RC, Thompson PJ, Light RW
JournalAm J Physiol Lung Cell Mol Physiol
PubMed ID15591415
'Pleural inflammation underlies many pleural diseases, but its pathogenesis remains unclear. Proteinase-activated receptor-2 (PAR(2)) is a novel seven-transmembrane receptor with immunoregulatory roles. We hypothesized that PAR(2) is present on mesothelial cells and can induce pleural inflammation. PAR(2) was detected by immunohistochemistry in all (19 parietal and 11 visceral) human pleural ... More
beta1 integrin and organized actin filaments facilitate cardiomyocyte-specific RhoA-dependent activation of the skeletal alpha-actin promoter.
AuthorsWei L, Wang L, Carson JA, Agan JE, Imanaka-Yoshida K, Schwartz RJ
JournalFASEB J
PubMed ID11259397
'Activation of RhoA GTPase causes actin filament bundling into stress fibers, integrin clustering, and focal adhesion formation through its action on actin cytoskeleton organization. RhoA also regulates transcriptional activity of serum response factor (SRF). Recent studies in NIH 3T3 fibroblasts have shown that SRF activation by RhoA does not require ... More
Facilitation of Ca(2+)-dependent exocytosis by Rac1-GTPase in bovine chromaffin cells.
AuthorsLi Q, Ho CS, Marinescu V, Bhatti H, Bokoch GM, Ernst SA, Holz RW, Stuenkel EL
JournalJ Physiol
PubMed ID12754309
'Rho family GTPases are primary mediators of cytoskeletal reorganization, although they have also been reported to regulate cell secretion. Yet, the extent to which Rho family GTPases are activated by secretory stimuli in neural and neuroendocrine cells remains unknown. In bovine adrenal chromaffin cells, we found Rac1, but not Cdc42, ... More
Involvement of nectin in the localization of IQGAP1 at the cell-cell adhesion sites through the actin cytoskeleton in Madin-Darby canine kidney cells.
AuthorsKatata T, Irie K, Fukuhara A, Kawakatsu T, Yamada A, Shimizu K, Takai Y
JournalOncogene
PubMed ID12687012
'IQGAP1, a putative downstream target of the Rho family small G proteins, Cdc42 and Rac, localizes at adherens junctions (AJs) in epithelial cells. It has been suggested that IQGAP1 localizes at AJs through its binding to beta-catenin, and negatively regulates the E-cadherin-mediated cell-cell adhesion. Nectin is a Ca(2+)-independent, immunoglobulin-like cell-cell ... More
Identification of a novel sequence in PDZ-RhoGEF that mediates interaction with the actin cytoskeleton.
AuthorsBanerjee J, Wedegaertner PB
JournalMol Biol Cell
PubMed ID14742719
'Small GTPases of the Rho family are crucial regulators of actin cytoskeleton rearrangements. Rho is activated by members of the Rho guanine-nucleotide exchange factor (GEF) family; however, mechanisms that regulate RhoGEFs are not well understood. This report demonstrates that PDZ-RhoGEF, a member of a subfamily of RhoGEFs that contain regulator ... More
Anemonefish symbiosis: vulnerability and resistance of fish to the toxin of the sea anemone.
AuthorsMebs D
JournalToxicon
PubMed ID7801342
'Protein toxins (20 kD molecular mass) causing lysis of human erythrocytes were isolated from sea anemones (Heteractis magnifica, Madang, Papua New Guinea, and Entacmaea quadricolor, Red Sea), which host anemonefish (Amphiprion sp.). These toxins are also ichthyotoxic. Freshwater and marine fish exposed to toxin concentrations of 0.5 micrograms/ml water were ... More
Sla1p couples the yeast endocytic machinery to proteins regulating actin dynamics.
'Sla1p is a protein required for cortical actin patch structure and organisation in budding yeast. Here we use a combination of immunofluorescence microscopy and biochemical approaches to demonstrate interactions of Sla1p both with proteins regulating actin dynamics and with proteins required for endocytosis. Using Sla1p-binding studies we reveal association of ... More
The M-phase-promoting factor modulates the sensitivity of the Ca2+ stores to inositol 1,4,5-trisphosphate via the actin cytoskeleton.
AuthorsLim D, Ercolano E, Kyozuka K, Nusco GA, Moccia F, Lange K, Santella L
JournalJ Biol Chem
PubMed ID12867432
'The resumption of the meiotic cycle (maturation) induced by 1-methyladenine in prophase-arrested starfish oocytes is indicated by the breakdown of the germinal vesicle and is characterized by the increased sensitivity of the Ca2+ stores to inositol 1,4,5-trisphosphate (InsP3) to InsP3 starting at the animal hemisphere (where the germinal vesicle was ... More
Marginal blebbing during the early stages of TNF-induced apoptosis indicates alteration in actomyosin contractility.
AuthorsDomnina LV, Ivanova OY, Pletjushkina OY, Fetisova EK, Chernyak BV, Skulachev VP, Vasiliev JM
JournalCell Biol Int
PubMed ID15223024
'Dynamics of alterations of cell surface topography during TNF-induced apoptosis of HeLa cells was examined by phase-contrast videomicroscopy and immunomorphological analysis. The final stage of apoptosis accompanied by cell rounding and general blebbing of the cell surface became after 4-6 h of incubation but much earlier, after 1.5-3 h, essentially ... More
Synthesis of proto-oncogene proteins and cyclins depends on intact microfilaments.
AuthorsFasshauer M, Iwig M, Glaesser D
JournalEur J Cell Biol
PubMed ID9860134
'It is well established that microfilament disintegration by cytochalasin D (CD) as well as latrunculin (LAT)-A and LAT-B causes an inhibition of S phase entry of various nontransformed cell lines. Our experiments extended these observations to human embryonal diploid fibroblasts (Wi-38). To investigate the question whether this stop of DNA ... More
Continuous translocation of Rac2 and the NADPH oxidase component p67(phox) during phagocytosis.
Authorsvan Bruggen R, Anthony E, Fernandez-Borja M, Roos D
JournalJ Biol Chem
PubMed ID14623873
'In this study, the translocation of the NADPH oxidase components p67(phox) and Rac2 was studied during phagocytosis in living cells. For this purpose, green fluorescent protein (GFP)-tagged versions of these proteins were expressed in the myeloid cell line PLB-985. First, the correct localization of p67GFP and GFP-Rac2 was shown during ... More
Two pathways for store-mediated calcium entry differentially dependent on the actin cytoskeleton in human platelets.
'A major pathway for stimulated Ca(2+) entry in non-excitable cells is activated following depletion of intracellular Ca(2+) stores. Secretion-like coupling between elements in the plasma membrane (PM) and Ca(2+) stores has been proposed as the most likely mechanism to activate this store-mediated Ca(2+) entry (SMCE) in several cell types. Here ... More
Endocytosis of E-cadherin regulated by Rac and Cdc42 small G proteins through IQGAP1 and actin filaments.
AuthorsIzumi G, Sakisaka T, Baba T, Tanaka S, Morimoto K, Takai Y
JournalJ Cell Biol
PubMed ID15263019
'E-cadherin is a key cell-cell adhesion molecule at adherens junctions (AJs) and undergoes endocytosis when AJs are disrupted by the action of extracellular signals. To elucidate the mechanism of this endocytosis, we developed here a new cell-free assay system for this reaction using the AJ-enriched fraction from rat liver. We ... More
Single-particle tracking of murine polyoma virus-like particles on live cells and artificial membranes.
AuthorsEwers H, Smith AE, Sbalzarini IF, Lilie H, Koumoutsakos P, Helenius A
JournalProc Natl Acad Sci U S A
PubMed ID16219700
'The lateral mobility of individual murine polyoma virus-like particles (VLPs) bound to live cells and artificial lipid bilayers was studied by single fluorescent particle tracking using total internal reflection fluorescence microscopy. The particle trajectories were analyzed in terms of diffusion rates and modes of motion as described by the moment ... More
PtdIns(3,4,5)P3 binding is necessary for WAVE2-induced formation of lamellipodia.
AuthorsOikawa T, Yamaguchi H, Itoh T, Kato M, Ijuin T, Yamazaki D, Suetsugu S, Takenawa T
JournalNat Cell Biol
PubMed ID15107862
'Polarized cell movement is triggered by the development of a PtdIns(3,4,5)P(3) gradient at the membrane, which is followed by rearrangement of the actin cytoskeleton. The WASP family verprolin homologous protein (WAVE) is essential for lamellipodium formation at the leading edge by activating the Arp2/3 complex downstream of Rac GTPase. Here, ... More
EFA6, exchange factor for ARF6, regulates the actin cytoskeleton and associated tight junction in response to E-cadherin engagement.
AuthorsLuton F, Klein S, Chauvin JP, Le Bivic A, Bourgoin S, Franco M, Chardin P
JournalMol Biol Cell
PubMed ID14668475
'We addressed the role of EFA6, exchange factor for ARF6, during the development of epithelial cell polarity in Madin-Darby canine kidney cells. EFA6 is located primarily at the apical pole of polarized cells, including the plasma membrane. After calcium-triggered E-cadherin-mediated cell adhesion, EFA6 is recruited to a Triton X-100-insoluble fraction ... More
Lymphocyte microvilli are dynamic, actin-dependent structures that do not require Wiskott-Aldrich syndrome protein (WASp) for their morphology.
AuthorsMajstoravich S, Zhang J, Nicholson-Dykstra S, Linder S, Friedrich W, Siminovitch KA, Higgs HN
JournalBlood
PubMed ID15130947
'Short microvilli cover the surfaces of circulating mammalian lymphocytes. The surfaces of monocytes and neutrophils are very different, containing ruffles as their predominant structure. In this study, we present the first quantitative characterization of lymphocyte microvilli. From analysis of scanning electron micrographs, we find that median microvillar length and surface ... More
Yeast osmosensor Sln1 and plant cytokinin receptor Cre1 respond to changes in turgor pressure.
AuthorsReiser V, Raitt DC, Saito H
JournalJ Cell Biol
PubMed ID12821642
'Very little is known about how cellular osmosensors monitor changes in osmolarity of the environment. Here, we report that in yeast, Sln1 osmosensor histidine kinase monitors changes in turgor pressures. Reductions in turgor caused by either hyperosmotic stress, nystatin, or removal of cell wall activate MAPK Hog1 specifically through the ... More
Concurrent signaling from Galphaq- and Galphai-coupled pathways is essential for agonist-induced alphavbeta3 activation on human platelets.
'The integrin alphavbeta3 mediates platelet adhesion to the matrix protein osteopontin and likely is the predominant integrin mediating platelet adhesion to the matrix protein vitronectin. To address the mechanism that regulates alphavbeta3 activity in platelets, we measured the effect of the P2Y1 antagonist adenosine 3''-phosphate-5''-phosphate (A3P5P) and the P2Y12 antagonist ... More
Pressure-induced actin polymerization in vascular smooth muscle as a mechanism underlying myogenic behavior.
AuthorsCipolla MJ, Gokina NI, Osol G
JournalFASEB J
PubMed ID11772938
'We hypothesize that actin polymerization within vascular smooth muscle (VSM) in response to increased intravascular pressure is a novel and previously unrecognized mechanism underlying arterial myogenic behavior. This hypothesis is based on the following observations. 1) Unlike skeletal or cardiac muscle, VSM contains a substantial pool of unpolymerized globular (G) ... More
The yeast dynamin-related GTPase Vps1p functions in the organization of the actin cytoskeleton via interaction with Sla1p.
AuthorsYu X, Cai M
JournalJ Cell Sci
PubMed ID15265985
'Recent studies have suggested that the function of the large GTPase dynamin in endocytosis in mammalian cells may comprise a modulation of actin cytoskeleton. The role of dynamin in actin cytoskeleton organization in the yeast Saccharomyces cerevisiae has remained undefined. In this report, we found that one of the yeast ... More
The state of actin assembly regulates actin and vinculin expression by a feedback loop.
AuthorsBershadsky AD, Glück U, Denisenko ON, Sklyarova TV, Spector I, Ben-Ze'ev A
JournalJ Cell Sci
PubMed ID7542668
'Actin filaments are major determinants of cell shape, motility and adhesion, which control important biological processes including embryonic development and wound healing. These processes are associated with changes in actin assembly, which is regulated by controlling the balance between polymerized and non-polymerized actin. To maintain a significant pool of non-polymerized ... More
Signaling through integrin LFA-1 leads to filamentous actin polymerization and remodeling, resulting in enhanced T cell adhesion.
AuthorsPorter JC, Bracke M, Smith A, Davies D, Hogg N
JournalJ Immunol
PubMed ID12055249
'The integrins can activate signaling pathways, but the final downstream outcome of these pathways is often unclear. This study analyzes the consequences of signaling events initiated by the interaction of the leukocyte integrin LFA-1 with its ligand, dimeric ICAM-1. We show that the active form of LFA-1 regulates its own ... More
GCS1, an Arf guanosine triphosphatase-activating protein in Saccharomyces cerevisiae, is required for normal actin cytoskeletal organization in vivo and stimulates actin polymerization in vitro.
AuthorsBlader IJ, Cope MJ, Jackson TR, Profit AA, Greenwood AF, Drubin DG, Prestwich GD, Theibert AB
JournalMol Biol Cell
PubMed ID10069805
'Recent cloning of a rat brain phosphatidylinositol 3,4, 5-trisphosphate binding protein, centaurin alpha, identified a novel gene family based on homology to an amino-terminal zinc-binding domain. In Saccharomyces cerevisiae, the protein with the highest homology to centaurin alpha is Gcs1p, the product of the GCS1 gene. GCS1 was originally identified ... More
The actin cytoskeleton facilitates complement-mediated activation of cytosolic phospholipase A2.
AuthorsCybulsky AV, Takano T, Papillon J, Khadir A, Bijian K, Le Berre L
JournalAm J Physiol Renal Physiol
PubMed ID14644750
'Cytosolic PLA(2)-alpha (cPLA(2)) and metabolites of arachidonic acid (AA) are key mediators of complement-dependent glomerular epithelial cell (GEC) injury. Assembly of C5b-9 increases cytosolic Ca(2+) concentration and results in transactivation of receptor tyrosine kinases and activation of PLC-gamma 1 and the 1,2-diacylglycerol (DAG)-PKC pathway. Ca(2+) and PKC are essential for ... More
Mechanism of actin polymerization in cellular ATP depletion.
AuthorsAtkinson SJ, Hosford MA, Molitoris BA
JournalJ Biol Chem
PubMed ID14623892
'Cellular ATP depletion in diverse cell types results in the net conversion of monomeric G-actin to polymeric F-actin and is an important aspect of cellular injury in tissue ischemia. We propose that this conversion results from altering the ratio of ATP-G-actin and ADP-G-actin, causing a net decrease in the concentration ... More
Effects of latrunculin A on immunological phagocytosis and macrophage spreading-associated changes in the F-actin/G-actin content of the cells.
AuthorsOliveira CA, Kashman Y, Mantovani B
JournalChem Biol Interact
PubMed ID8646787
'Latrunculin A, a toxin from a Red Sea sponge, was shown to be a very potent inhibitor of immunological phagocytosis by normal and activated macrophages (obtained from mice injected i.p. with LPS), as well as by polymorphonuclear leukocytes. This toxin blocks the interiorization of the immune complexes but does not ... More
Tumor necrosis factor-alpha inhibits store-mediated Ca2+ entry in the human hepatocellular carcinoma cell line HepG2.
AuthorsRosado JA, Rosenzweig I, Harding S, Sage SO
JournalAm J Physiol Cell Physiol
PubMed ID11350760
'Tumor necrosis factor-alpha (TNF-alpha) is an important component of the early signaling pathways leading to liver regeneration and proliferation, but it is also responsible for several hepatotoxic effects. We have investigated the effect of TNF-alpha on thapsigargin (TG)-induced store-mediated Ca2+ entry (SMCE) in the human hepatocellular carcinoma cell line HepG2. ... More
Lis1 and doublecortin function with dynein to mediate coupling of the nucleus to the centrosome in neuronal migration.
'Humans with mutations in either DCX or LIS1 display nearly identical neuronal migration defects, known as lissencephaly. To define subcellular mechanisms, we have combined in vitro neuronal migration assays with retroviral transduction. Overexpression of wild-type Dcx or Lis1, but not patient-related mutant versions, increased migration rates. Dcx overexpression rescued the ... More
Cofilin promotes stimulus-induced lamellipodium formation by generating an abundant supply of actin monomers.
AuthorsKiuchi T, Ohashi K, Kurita S, Mizuno K
JournalJ Cell Biol
PubMed ID17470633
'Cofilin stimulates actin filament disassembly and accelerates actin filament turnover. Cofilin is also involved in stimulus-induced actin filament assembly during lamellipodium formation. However, it is not clear whether this occurs by replenishing the actin monomer pool, through filament disassembly, or by creating free barbed ends, through its severing activity. Using ... More
Plant and animal profilins are functionally equivalent and stabilize microfilaments in living animal cells.
AuthorsRothkegel M, Mayboroda O, Rohde M, Wucherpfennig C, Valenta R, Jockusch BM
JournalJ Cell Sci
PubMed ID8834793
'We have analyzed the degree of functional similarity between birth and mammalian profilins, two members of the profilin family which show only a moderate sequence homology (22%) in living animal cells. The plant profilin, derived from birch pollen, was stably expressed in BHK-21 cells. Plant and endogenous profilin synthesis and ... More
Overexpression of myosin IB in living Entamoeba histolytica enhances cytoplasm viscosity and reduces phagocytosis.
AuthorsMarion S, Wilhelm C, Voigt H, Bacri JC, Guillén N
JournalJ Cell Sci
PubMed ID15226399
'The human parasite Entamoeba histolytica is an ancient protozoan that expresses only one unconventional myosin, which has homology with myosin IB from other amoebae. Myosin IB is involved in phagocytosis of human cells by E. histolytica. In this work, we developed a microrheological technique, analysing magnetic phagosomes, which allowed us ... More
Cellular regulation of sodium-calcium exchange.
AuthorsCondrescu M, Opuni K, Hantash BM, Reeves JP
JournalAnn N Y Acad Sci
PubMed ID12502564
'Na(+)/Ca(2+) exchange activity was studied in transfected Chinese hamster ovary (CHO) cells expressing the wild-type cardiac exchanger (NCX1.1) or mutants created by site-directed mutagenesis. The activity of the wild-type exchanger, but not exchanger mutants deficient in Ca(2+)-dependent activation, was inhibited by sphingolipids such as ceramide and sphingosine. We propose that ... More
The PXL1 gene of Saccharomyces cerevisiae encodes a paxillin-like protein functioning in polarized cell growth.
AuthorsMackin NA, Sousou TJ, Erdman SE
JournalMol Biol Cell
PubMed ID14767053
'The Saccharomyces cerevisiae open reading frame YKR090w encodes a predicted protein displaying similarity in organization to paxillin, a scaffolding protein that organizes signaling and actin cytoskeletal regulating activities in many higher eucaryotic cell types. We found that YKR090w functions in a manner analogous to paxillin as a mediator of polarized ... More
Spatial control of coated-pit dynamics in living cells.
AuthorsGaidarov I, Santini F, Warren RA, Keen JH
JournalNat Cell Biol
PubMed ID10559856
'Here we visualize new aspects of the dynamics of endocytotic clathrin-coated pits and vesicles in mammalian cells by using a fusion protein consisting of green fluorescent protein and clathrin light chain a. Clathrin-coated pits invaginating from the plasma membrane show definite, but highly limited, mobility within the membrane that is ... More
Actin filaments play a permissive role in the inhibition of store-operated Ca2+ entry by extracellular ATP in rat brown adipocytes.
AuthorsOmatsu-Kanbe M, Shibata M, Yamamoto T, Isono T, Matsuura H
JournalBiochem J
PubMed ID15107014
'Stimulation of P2 receptors with micromolar concentration of ATP evokes a transient increase in [Ca2+]i (intracellular free Ca2+ concentration), primarily due to release of Ca2+ from intracellular stores; such stimulation also triggers almost complete suppression of thapsigargin-evoked sustained [Ca2+]i increase mediated through a store-operated Ca2+ entry pathway in rat brown ... More
A novel role for microtubules in apoptotic chromatin dynamics and cellular fragmentation.
AuthorsMoss DK, Betin VM, Malesinski SD, Lane JD
JournalJ Cell Sci
PubMed ID16723742
'Dramatic changes in cellular dynamics characterise the apoptotic execution phase, culminating in fragmentation into membrane-bound apoptotic bodies. Previous evidence suggests that actin-myosin plays a dominant role in apoptotic cellular remodelling, whereas all other cytoskeletal elements dismantle. We have used fixed cells and live-cell imaging to confirm that interphase microtubules rapidly ... More
Cytoskeletal rearrangement and signal transduction in TGF-beta1-stimulated mesangial cell collagen accumulation.
AuthorsHubchak SC, Runyan CE, Kreisberg JI, Schnaper HW
JournalJ Am Soc Nephrol
PubMed ID12874450
'TGF-beta1 has been implicated in glomerular extracellular matrix accumulation, although the precise cellular mechanism(s) by which this occurs is not fully understood. The authors have previously shown that the Smad signaling pathway is present and functional in human glomerular mesangial cells and plays a role in activating type I collagen ... More
The Saccharomyces cerevisiae homologue of human Wiskott-Aldrich syndrome protein Las17p interacts with the Arp2/3 complex.
AuthorsMadania A, Dumoulin P, Grava S, Kitamoto H, Schärer-Brodbeck C, Soulard A, Moreau V, Winsor B
JournalMol Biol Cell
PubMed ID10512884
'Yeast Las17 protein is homologous to the Wiskott-Aldrich Syndrome protein, which is implicated in severe immunodeficiency. Las17p/Bee1p has been shown to be important for actin patch assembly and actin polymerization. Here we show that Las17p interacts with the Arp2/3 complex. LAS17 is an allele-specific multicopy suppressor of ARP2 and ARP3 ... More
Importance of mitochondrial dynamics during meiosis and sporulation.
AuthorsGorsich SW, Shaw JM
JournalMol Biol Cell
PubMed ID15254264
'Opposing fission and fusion events maintain the yeast mitochondrial network. Six proteins regulate these membrane dynamics during mitotic growth-Dnm1p, Mdv1p, and Fis1p mediate fission; Fzo1p, Mgm1p, and Ugo1p mediate fusion. Previous studies established that mitochondria fragment and rejoin at distinct stages during meiosis and sporulation, suggesting that mitochondrial fission and ... More
Contribution of cytoskeleton to the internalization of AMPA receptors.
AuthorsZhou Q, Xiao M, Nicoll RA
JournalProc Natl Acad Sci U S A
PubMed ID11158627
'Trafficking of alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors (AMPARs) at synapses has been suggested to play an important role in the expression of synaptic plasticity. Both the regulated and the constitutive trafficking of synaptic AMPARs are thought to involve the insertion and removal of receptors by means of an exocytotic and endocytotic ... More
Collagen I initiates endothelial cell morphogenesis by inducing actin polymerization through suppression of cyclic AMP and protein kinase A.
AuthorsWhelan MC, Senger DR
JournalJ Biol Chem
PubMed ID12399469
'Collagen I provokes endothelial cells to assume a spindle-shaped morphology and to align into solid cord-like assemblies. These cords closely imitate the solid pre-capillary cords of embryonic angiogenesis, raising interesting questions about underlying mechanisms. Studies described here identify a critical mechanism beginning with collagen I ligation of integrins alpha(1)beta(1) and ... More
Role for actin filament turnover and a myosin II motor in cytoskeleton-driven disassembly of the epithelial apical junctional complex.
AuthorsIvanov AI, McCall IC, Parkos CA, Nusrat A
JournalMol Biol Cell
PubMed ID15047870
'Disassembly of the epithelial apical junctional complex (AJC), composed of the tight junction (TJ) and adherens junction (AJ), is important for normal tissue remodeling and pathogen-induced disruption of epithelial barriers. Using a calcium depletion model in T84 epithelial cells, we previously found that disassembly of the AJC results in endocytosis ... More
Latrunculin B-induced plant dwarfism: Plant cell elongation is F-actin-dependent.
AuthorsBaluska F, Jasik J, Edelmann HG, Salajová T, Volkmann D
JournalDev Biol
PubMed ID11180956
'Marine macrolides latrunculins are highly specific toxins which effectively depolymerize actin filaments (generally F-actin) in all eukaryotic cells. We show that latrunculin B is effective on diverse cell types in higher plants and describe the use of this drug in probing F-actin-dependent growth and in plant development-related processes. In contrast ... More
The Src homology domain 3 (SH3) of a yeast type I myosin, Myo5p, binds to verprolin and is required for targeting to sites of actin polarization.
AuthorsAnderson BL, Boldogh I, Evangelista M, Boone C, Greene LA, Pon LA
JournalJ Cell Biol
PubMed ID9628892
'The budding yeast contains two type I myosins, Myo3p and Myo5p, with redundant functions. Deletion of both myosins results in growth defects, loss of actin polarity and polarized cell surface growth, and accumulation of intracellular membranes. Expression of myc-tagged Myo5p in myo3Delta myo5Delta cells fully restores wild-type characteristics. Myo5p is ... More
Motility and centrosomal organization during sea urchin and mouse fertilization.
AuthorsSchatten H, Schatten G
JournalCell Motil Cytoskeleton
PubMed ID3518956
'Motility and the behavior and inheritance of centrosomes are investigated during mouse and sea urchin fertilization. Sperm incorporation in sea urchins requires microfilament activity in both sperm and eggs as tested with Latrunculin A, a novel inhibitor of microfilament assembly. In contrast the mouse spermhead is incorporated in the presence ... More
Modulation of 5-HT3 receptor-mediated response and trafficking by activation of protein kinase C.
AuthorsSun H, Hu XQ, Moradel EM, Weight FF, Zhang L
JournalJ Biol Chem
PubMed ID12791692
'Modulation of neurotransmitter-gated membrane ion channels by protein kinase C (PKC) has been the subject of a number of studies. However, less is known about PKC modulation of the serotonin type 3 (5-HT3) receptor, a ligand-gated membrane ion channel that can mediate fast synaptic transmission in the central and peripheral ... More
Myotilin, the limb-girdle muscular dystrophy 1A (LGMD1A) protein, cross-links actin filaments and controls sarcomere assembly.
AuthorsSalmikangas P, van der Ven PF, Lalowski M, Taivainen A, Zhao F, Suila H, Schröder R, Lappalainen P, Fürst DO, Carpén O
JournalHum Mol Genet
PubMed ID12499399
'The assembly and maintenance of the muscle sarcomere requires a complex interplay of actin- and myosin-associated proteins. Myotilin is a thin filament-associated Z-disc protein that consists of two Ig-domains flanked by a unique serine-rich amino-terminus and a short carboxy-terminal tail. It binds to alpha-actinin and filamin c and is mutated ... More
Visualization of antigen presentation by actin-mediated targeting of glycolipid-enriched membrane domains to the immune synapse of B cell APCs.
AuthorsGordy C, Mishra S, Rodgers W
JournalJ Immunol
PubMed ID14764667
'Glycolipid-enriched membrane (GEM) domains, or lipid rafts, function in signaling in immune cells, but their properties during Ag presentation are less clear. To address this question, GEM domains were studied using fluorescence cell imaging of mouse CH27 B cells presenting Ag to D10 T cells. Our experiments showed that APCs ... More
Evaluation of marine sponge metabolites for cytotoxicity and signal transduction activity.
AuthorsLongley RE, McConnell OJ, Essich E, Harmody D
JournalJ Nat Prod
PubMed ID8350092
'Twenty-four metabolites derived from marine sponges were evaluated for their cytotoxicities against two human tumor cell lines, non-small cell lung carcinoma A549 and colon adenocarcinoma HT-29, and against one murine leukemia cell line, P-388, and evaluated for their ability to effect signal transduction in a newly developed cell adhesion assay ... More
Differential regulation of actin depolymerizing factor and cofilin in response to alterations in the actin monomer pool.
AuthorsMinamide LS, Painter WB, Schevzov G, Gunning P, Bamburg JR
JournalJ Biol Chem
PubMed ID9079652
'Myoblasts, transfected with a human gene encoding a beta-actin point mutation, down-regulate expression of actin depolymerizing factor (ADF) and its mRNA. Regulation is posttranscriptional. Expression of cofilin, a structurally similar protein, and profilin, CapG, and tropomodulin is not altered with increasing mutant beta-actin expression. Myoblasts expressing either human gamma-actin or ... More
Actin dependence of polarized receptor recycling in Madin-Darby canine kidney cell endosomes.
AuthorsSheff DR, Kroschewski R, Mellman I
JournalMol Biol Cell
PubMed ID11809838
'Mammalian epithelial cell plasma membrane domains are separated by junctional complexes supported by actin. The extent to which actin acts elsewhere to maintain cell polarity remains poorly understood. Using latrunculin B (Lat B) to depolymerize actin filaments, several basolateral plasma membrane proteins were found to lose their polarized distribution. This ... More
HIV-1 cell to cell transfer across an Env-induced, actin-dependent synapse.
AuthorsJolly C, Kashefi K, Hollinshead M, Sattentau QJ
JournalJ Exp Med
PubMed ID14734528
'Direct cell-cell transfer is an efficient mechanism of viral dissemination within an infected host, and human immunodeficiency virus 1 (HIV-1) can exploit this mode of spread. Receptor recognition by HIV-1 occurs via interactions between the viral surface envelope glycoprotein (Env), gp120, and CD4 and a chemokine receptor, CCR5 or CXCR4. ... More
The actin cytoskeleton is required for receptor-mediated endocytosis in mammalian cells.
AuthorsLamaze C, Fujimoto LM, Yin HL, Schmid SL
JournalJ Biol Chem
PubMed ID9252336
'Actin filament organization is essential for endocytosis in yeast. In contrast, the actin-depolymerizing agent cytochalasin D has yielded ambiguous results as to a role for actin in receptor-mediated endocytosis in mammalian cells. We have therefore re-examined this issue using highly specific reagents known to sequester actin monomers. Two of these ... More
Synergistic assembly of linker for activation of T cells signaling protein complexes in T cell plasma membrane domains.
AuthorsHartgroves LC, Lin J, Langen H, Zech T, Weiss A, Harder T
JournalJ Biol Chem
PubMed ID12646565
'Transmembrane adaptor molecule LAT (linker for activation of T cells) forms a central scaffold for signaling protein complexes that accumulate in the vicinity of activated T cell antigen receptors (TCR). Here we used biochemical analysis of immunoisolated plasma membrane domains and fluorescence imaging of green fluorescence protein-tagged signaling proteins to ... More
Actin coating of secretory granules during regulated exocytosis correlates with the release of rab3D.
'The present study describes a novel phenomenon in pancreatic acinar cells undergoing regulated exocytosis. When acinar cell preparations were challenged with the secretagogue carbamylcholine, a subpopulation of zymogen granules became coated with filamentous actin. These zymogen granules were always in proximity of the acinar cell apical membrane (the site of ... More
Cell penetration and trafficking of polyomavirus.
AuthorsGilbert JM, Goldberg IG, Benjamin TL
JournalJ Virol
PubMed ID12552000
'The murine polyomavirus (Py) enters mouse fibroblasts and kidney epithelial cells via an endocytic pathway that is caveola-independent (as well as clathrin-independent). In contrast, uptake of simian virus 40 into the same cells is dependent on caveola. Following the initial uptake of Py, both microtubules and microfilaments play roles in ... More
Novel mechanism of PTEN regulation by its phosphatidylinositol 4,5-bisphosphate binding motif is critical for chemotaxis.
AuthorsIijima M, Huang YE, Luo HR, Vazquez F, Devreotes PN
JournalJ Biol Chem
PubMed ID14764604
'In chemotaxing cells, localization of phosphatidylinositol 3,4,5-trisphosphate (PI(3,4,5)P3) to the leading edge of the cell sets the direction and regulates the formation of pseudopods at the anterior. We show that the lipid phosphatase activity of PTEN mediates chemotaxis and that the sharp localization of PI(3,4,5)P3 requires localization of PTEN to ... More
Membrane lipid rafts are necessary for the maintenance of the (alpha)7 nicotinic acetylcholine receptor in somatic spines of ciliary neurons.
AuthorsBrusés JL, Chauvet N, Rutishauser U
JournalJ Neurosci
PubMed ID11160430
'Calcium-permeable neurotransmitter receptors are concentrated into structurally and biochemically isolated cellular compartments to localize calcium-mediated events during neurotransmission. The cytoplasmic membrane contains lipid microdomains called lipid rafts, which can gather into microscopically visible clusters, and thus the association of a particular protein with lipid rafts can result in its redistribution ... More
cdc42 regulates the exit of apical and basolateral proteins from the trans-Golgi network.
AuthorsMüsch A, Cohen D, Kreitzer G, Rodriguez-Boulan E
JournalEMBO J
PubMed ID11331583
'It is well established that Rho-GTPases regulate vesicle fusion and fission events at the plasma membrane through their modulatory role on the cortical actin cytoskeleton. In contrast, their effects on intracellular transport processes and actin pools are less clear. It was recently shown that cdc42 associates with the Golgi apparatus ... More
Truncated brush border myosin I affects membrane traffic in polarized epithelial cells.
AuthorsDurrbach A, Raposo G, Tenza D, Louvard D, Coudrier E
JournalTraffic
PubMed ID11208127
'We investigate, in this study, the potential involvement of an acto-myosin-driven mechanism in endocytosis of polarized cells. We observed that depolymerization of actin filaments using latrunculin A decreases the rate of transferrin recycling to the basolateral plasma membrane of Caco-2 cells, and increases its delivery to the apical plasma membrane. ... More
Intracellular trafficking of bile salt export pump (ABCB11) in polarized hepatic cells: constitutive cycling between the canalicular membrane and rab11-positive endosomes.
AuthorsWakabayashi Y, Lippincott-Schwartz J, Arias IM
JournalMol Biol Cell
PubMed ID15121884
'The bile salt export pump (BSEP, ABCB11) couples ATP hydrolysis with transport of bile acids into the bile canaliculus of hepatocytes. Its localization in the apical canalicular membrane is physiologically regulated by the demand to secrete biliary components. To gain insight into how such localization is regulated, we studied the ... More
An essential role for Rac/Cdc42 GTPases in cerebellar granule neuron survival.
AuthorsLinseman DA, Laessig T, Meintzer MK, McClure M, Barth H, Aktories K, Heidenreich KA
JournalJ Biol Chem
PubMed ID11509562
'Rho family GTPases are critical molecular switches that regulate the actin cytoskeleton and cell function. In the current study, we investigated the involvement of Rho GTPases in regulating neuronal survival using primary cerebellar granule neurons. Clostridium difficile toxin B, a specific inhibitor of Rho, Rac, and Cdc42, induced apoptosis of ... More
Rab27A and its effector MyRIP link secretory granules to F-actin and control their motion towards release sites.
AuthorsDesnos C, Schonn JS, Huet S, Tran VS, El-Amraoui A, Raposo G, Fanget I, Chapuis C, Ménasché G, de Saint Basile G, Petit C, Cribier S, Henry JP, Darchen F
JournalJ Cell Biol
PubMed ID14610058
'The GTPase Rab27A interacts with myosin-VIIa and myosin-Va via MyRIP or melanophilin and mediates melanosome binding to actin. Here we show that Rab27A and MyRIP are associated with secretory granules (SGs) in adrenal chromaffin cells and PC12 cells. Overexpression of Rab27A, GTPase-deficient Rab27A-Q78L, or MyRIP reduced secretory responses of PC12 ... More
Cyclase-associated protein 1 (CAP1) promotes cofilin-induced actin dynamics in mammalian nonmuscle cells.
AuthorsBertling E, Hotulainen P, Mattila PK, Matilainen T, Salminen M, Lappalainen P
JournalMol Biol Cell
PubMed ID15004221
'Cyclase-associated proteins (CAPs) are highly conserved actin monomer binding proteins present in all eukaryotes. However, the mechanism by which CAPs contribute to actin dynamics has been elusive. In mammals, the situation is further complicated by the presence of two CAP isoforms whose differences have not been characterized. Here, we show ... More
Epithelial cell polarity alters Rho-GTPase responses to Pseudomonas aeruginosa.
AuthorsKazmierczak BI, Mostov K, Engel JN
JournalMol Biol Cell
PubMed ID14595106
'Pseudomonas aeruginosa is an opportunistic human pathogen that preferentially infects damaged epithelial tissues. Previous studies have failed to distinguish whether the increased susceptibility of injured epithelium results from the loss of cell polarity or increased access to the basolateral surface. We have used confluent monolayers of Madin-Darby canine kidney (MDCK) ... More
Local force induced conical protrusions of phagocytic cells.
AuthorsVonna L, Wiedemann A, Aepfelbacher M, Sackmann E
JournalJ Cell Sci
PubMed ID12571276
'Magnetic tweezers were used to study the passive and active response of macrophages to local centripetal nanonewton forces on beta1 integrins. Superparamagnetic beads coated with the beta1-integrin-binding protein invasin were attached to J774 murine macrophages to mimic phagocytosis of bacterial pathogens. Forces exceeding approximately 0.5 nN induce the active formation ... More
Microtubules remodel actomyosin networks in Xenopus egg extracts via two mechanisms of F-actin transport.
'Interactions between microtubules and filamentous actin (F-actin) are crucial for many cellular processes, including cell locomotion and cytokinesis, but are poorly understood. To define the basic principles governing microtubule/F-actin interactions, we used dual-wavelength digital fluorescence and fluorescent speckle microscopy to analyze microtubules and F-actin labeled with spectrally distinct fluorophores in ... More
Hierarchy of protein assembly at the vertex ring domain for yeast vacuole docking and fusion.
AuthorsWang L, Merz AJ, Collins KM, Wickner W
JournalJ Cell Biol
PubMed ID12566429
'Vacuole tethering, docking, and fusion proteins assemble into a "vertex ring" around the apposed membranes of tethered vacuoles before catalyzing fusion. Inhibitors of the fusion reaction selectively interrupt protein assembly into the vertex ring, establishing a causal assembly hierarchy: (a) The Rab GTPase Ypt7p mediates vacuole tethering and forms the ... More
Cationic gradient reversal and cytoskeleton-independent volume regulatory pathways define an early stage of apoptosis.
AuthorsBortner CD, Sifre MI, Cidlowski JA,
JournalJ Biol Chem
PubMed ID18187415
'Cell shrinkage, or apoptotic volume decrease (AVD), is a ubiquitous characteristic of programmed cell death that is independent of the death stimulus and occurs in all examples of apoptosis. Here we distinguished two specific stages of AVD based on cell size and a unique early reversal of intracellular ions that ... More
Visualizing postendocytic traffic of synaptic vesicles at hippocampal synapses.
AuthorsLi Z, Murthy VN
JournalNeuron
PubMed ID11545718
'We have investigated mechanisms in postendocytic processing of synaptic vesicles at hippocampal synapses, using synaptobrevin/vesicle-associated membrane protein (VAMP) tagged with variants of the green fluorescent protein. Following exocytosis, VAMP is retrieved at synaptic and adjoining axonal regions. Retrieved VAMP-containing vesicles return to synaptic vesicle clusters at a rate slower than ... More
Macrophage podosomes assemble at the leading lamella by growth and fragmentation.
AuthorsEvans JG, Correia I, Krasavina O, Watson N, Matsudaira P
JournalJ Cell Biol
PubMed ID12756237
'Podosomes are actin- and fimbrin-containing adhesions at the leading edge of macrophages. In cells transfected with beta-actin-ECFP and L-fimbrin-EYFP, quantitative four-dimensional microscopy of podosome assembly shows that new adhesions arise at the cell periphery by one of two mechanisms; de novo podosome assembly, or fission of a precursor podosome into ... More
Effects of F-actin stabilization or disassembly on epithelial Cl- secretion and Na-K-2Cl cotransport.
AuthorsMatthews JB, Smith JA, Hrnjez BJ
JournalAm J Physiol
PubMed ID9038831
'Previous studies showed that cAMP-dependent transepithelial Cl- secretion of the intestinal cell line T84 is reduced by the F-actin stabilizer phalloidin, an effect in part attributable to inhibition of basolateral Na-K-2Cl cotransport. However, secretory responses are preserved in cells treated with the microfilament disrupter cytochalasin D. We explored the effects ... More
Cell wall stress depolarizes cell growth via hyperactivation of RHO1.
AuthorsDelley PA, Hall MN
JournalJ Cell Biol
PubMed ID10508863
'Cells sense and physiologically respond to environmental stress via signaling pathways. Saccharomyces cerevisiae cells respond to cell wall stress by transiently depolarizing the actin cytoskeleton. We report that cell wall stress also induces a transient depolarized distribution of the cell wall biosynthetic enzyme glucan synthase FKS1 and its regulatory subunit ... More
Cellular asymmetry and individuality in directional sensing.
AuthorsSamadani A, Mettetal J, van Oudenaarden A
JournalProc Natl Acad Sci U S A
PubMed ID16864788
'It is generally assumed that single cells in an isogenic population, when exposed to identical environments, exhibit the same behavior. However, it is becoming increasingly clear that, even in a genetically identical population, cellular behavior can vary significantly among cells. Here we explore this variability in the gradient-sensing response of ... More
Subcellular positioning of small molecules.
AuthorsTakayama S, Ostuni E, LeDuc P, Naruse K, Ingber DE, Whitesides GM
JournalNature
PubMed ID11429594
Cytomechanical properties of papaver pollen tubes are altered after self-incompatibility challenge.
AuthorsGeitmann A, McConnaughey W, Lang-Pauluzzi I, Franklin-Tong VE, Emons AM
JournalBiophys J
PubMed ID15111444
'Self-incompatibility (SI) in Papaver rhoeas triggers a ligand-mediated signal transduction cascade, resulting in the inhibition of incompatible pollen tube growth. Using a cytomechanical approach we have demonstrated that dramatic changes to the mechanical properties of incompatible pollen tubes are stimulated by SI induction. Microindentation revealed that SI resulted in a ... More
A role for actin dynamics in individualization during spermatogenesis in Drosophila melanogaster.
AuthorsNoguchi T, Miller KG
JournalDevelopment
PubMed ID12642486
'In order to better understand the mechanism of sperm individualization during spermatogenesis in Drosophila melanogaster, we have developed an in vitro culture system in which we can perform live observation of individualization in isolated cysts. The whole process of individualization, during which a bundle of 64 syncytial spermatids is separated ... More