'Shigella flexneri, the causative agent of bacillary dysentery, has the ability to enter nonphagocytic cells. The interferon (IFN) family of cytokines was found to inhibit Shigella invasion of cultured epithelial cells. We show here that IFN-alpha inhibits a Src-dependent signaling cascade triggered by Shigella that leads to the reorganization of ... More
Molecular characterization of abLIM, a novel actin-binding and double zinc finger protein.
AuthorsRoof DJ, Hayes A, Adamian M, Chishti AH, Li T
JournalJ Cell Biol
PubMed ID9245787
'Molecules that couple the actin-based cytoskeleton to intracellular signaling pathways are central to the processes of cellular morphogenesis and differentiation. We have characterized a novel protein, the actin-binding LIM (abLIM) protein, which could mediate such interactions between actin filaments and cytoplasmic targets. abLIM protein consists of a COOH-terminal cytoskeletal domain ... More
A role for the p38 mitogen-activated protein kinase pathway in myocardial cell growth, sarcomeric organization, and cardiac-specific gene expression.
AuthorsZechner D, Thuerauf DJ, Hanford DS, McDonough PM, Glembotski CC
JournalJ Cell Biol
PubMed ID9314533
'Three hallmark features of the cardiac hypertrophic growth program are increases in cell size, sarcomeric organization, and the induction of certain cardiac-specific genes. All three features of hypertrophy are induced in cultured myocardial cells by alpha1- adrenergic receptor agonists, such as phenylephrine (PE) and other growth factors that activate mitogen- ... More
Characterization of membrane and cytoskeletal compartments in cultured parietal cells: immunofluorescence and confocal microscopic examination.
AuthorsSoroka CJ, Chew CS, Hanzel DK, Smolka A, Modlin IM, Goldenring JR
JournalEur J Cell Biol
PubMed ID8385019
'Primary cultures of rabbit gastric parietal cells respond to various gastric secretagogues as evidenced by morphological alterations and [14C]aminopyrine uptake. The availability of cultures of > 95% purity has allowed us to utilize immunofluorescence and confocal microscopy to observe the direct effect of histamine upon the distribution of membrane and ... More
The role of the Shigella flexneri yihE gene in LPS synthesis and virulence.
'Previously, the authors have shown that inactivation of Shigella flexneri yihE, a gene of unknown function upstream of dsbA, which encodes a periplasmic disulphide catalyst, results in a global change of gene expression. Among the severely down-regulated genes are galETKM, suggesting that the yihE mutant, Sh54, may inefficiently produce the ... More
In vivo aggregation of beta-amyloid peptide variants.
AuthorsFay DS, Fluet A, Johnson CJ, Link CD
JournalJ Neurochem
PubMed ID9751195
'Transgenic Caenorhabditis elegans animals have been engineered to express wild-type and single-amino acid variants of a long form of human beta-amyloid peptide (A beta 1-42). These animals express high levels (approximately 300 ng of A beta/mg of total protein) of apparently full-length peptide, as determined by quantitative immunoblot. Expression of ... More
Neurite extension occurs in the absence of regulated exocytosis in PC12 subclones.
AuthorsLeoni C, Menegon A, Benfenati F, Toniolo D, Pennuto M, Valtorta F
JournalMol Biol Cell
PubMed ID10473636
'We have investigated the process leading to differentiation of PC12 cells. This process is known to include extension of neurites and changes in the expression of subsets of proteins involved in cytoskeletal rearrangements or in neurosecretion. To this aim, we have studied a PC12 clone (trk-PC12) stably transfected with the ... More
Vinculin proteolysis unmasks an ActA homolog for actin-based Shigella motility.
AuthorsLaine RO, Zeile W, Kang F, Purich DL, Southwick FS
JournalJ Cell Biol
PubMed ID9298981
'To generate the forces needed for motility, the plasma membranes of nonmuscle cells adopt an activated state that dynamically reorganizes the actin cytoskeleton. By usurping components from focal contacts and the actin cytoskeleton, the intracellular pathogens Shigella flexneri and Listeria monocytogenes use molecular mimicry to create their own actin-based motors. ... More
Variation in expression of hsp27 messenger ribonucleic acid during the cycle of the seminiferous epithelium and co-localization of hsp27 and microfilaments in Sertoli cells of the rat.
AuthorsWelsh MJ, Wu W, Parvinen M, Gilmont RR
JournalBiol Reprod
PubMed ID8793069
'The purpose of these studies was to define expression of hsp27 mRNA during the cycle of the seminiferous epithelium and to determine the distribution of hsp27 protein in the rat testis. To study hsp27 mRNA expression, a rat hsp27 cDNA was isolated and sequenced (GenBank no. M86389). The cDNA was ... More
Effect of cytotoxic necrotizing factor-1 on actin cytoskeleton in human monocytes: role in the regulation of integrin-dependent phagocytosis.
'Cytotoxic necrotizing factor-1 (CNF1) is isolated from pathogenic strains of Escherichia coli and catalyzes the activation of Rho GTPases by the deamidation of a glutamine residue. This toxin induces stress fiber formation, cell spreading, and membrane folding and promotes phagocytosis competence in epithelial cells. We show that CNF1 induces morphologic ... More
Distinct patterns of leukocyte recruitment in the pulmonary microvasculature in response to local and systemic inflammation.
AuthorsWang Y, Roller J, Slotta JE, Zhang S, Luo L, Rahman M, Syk I, Menger MD, Thorlacius H,
JournalAm J Physiol Lung Cell Mol Physiol
PubMed ID23275626
'The mechanisms of leukocyte recruitment in the pulmonary microvasculature in response to local and systemic inflammation remain elusive. Male C57BL/6 mice received lipopolysaccharide (LPS) intrapulmonary (intratracheally, it) or systemically (intravenously, iv) for 1-18 h. Leukocyte responses in lung were analyzed by use of intravital fluorescence microscopy. Plasma and lung levels ... More
Statistical evaluation of confocal microscopy images.
AuthorsZucker RM, Price OT
JournalCytometry
PubMed ID11500846
'BACKGROUND: The coefficient of variation (CV) is defined as the standard deviation (sigma) of the fluorescent intensity of a population of beads or pixels expressed as a proportion or percentage of the mean (mu) intensity (CV = sigma/mu). The field of flow cytometry has used the CV of a population ... More
Orientation and three-dimensional organization of actin filaments in dividing cultured cells.
AuthorsFishkind DJ, Wang YL
JournalJ Cell Biol
PubMed ID8227144
'The current hypothesis of cytokinesis suggests that contractile forces in the cleavage furrow are generated by a circumferential band of actin filaments. However, relatively little is known about the global organization of actin filaments in dividing cells. To approach this problem we have used fluorescence-detected linear dichroism (FDLD) microscopy to ... More
Sequences, structural models, and cellular localization of the actin-related proteins Arp2 and Arp3 from Acanthamoeba.
AuthorsKelleher JF, Atkinson SJ, Pollard TD
JournalJ Cell Biol
PubMed ID7593166
'We cloned and sequenced the two actin-related proteins (Arps) present in the profilin-binding complex of Acanthamoeba (Machesky, L. M., S. J. Atkinson, C. Ampe, J. Vandekerckhove, and T. D. Pollard. 1994, J. Cell Biol. 127:107-115). The sequence of Arp2 is more similar to other Arp2s than to actin, while the ... More
Coxiella burnetii induces reorganization of the actin cytoskeleton in human monocytes.
AuthorsMeconi S, Jacomo V, Boquet P, Raoult D, Mege JL, Capo C
JournalInfect Immun
PubMed ID9784567
'Coxiella burnetii, an obligate intracellular bacterium which survives in myeloid cells, causes Q fever in humans. We previously demonstrated that virulent C. burnetii organisms are poorly internalized by monocytes compared to avirulent variants. We hypothesized that a differential mobilization of the actin cytoskeleton may account for this distinct phagocytic behavior. ... More
Role of the cytoskeleton in calcium signaling in NIH 3T3 cells. An intact cytoskeleton is required for agonist-induced [Ca2+]i signaling, but not for capacitative calcium entry.
AuthorsRibeiro CM, Reece J, Putney JW
JournalJ Biol Chem
PubMed ID9334235
'Treatment of NIH 3T3 cells with cytochalasin D (10 microM, 1 h at 37 degrees C) disrupted the actin cytoskeleton and changed the cells from a planar, extended morphology, to a rounded shape. Calcium mobilization by ATP or by platelet-derived growth factor was abolished, while the ability of thapsigargin (2 ... More
Aluminum modifies the viscosity of filamentous actin solutions as measured by optical displacement microviscometry.
AuthorsArnoys EJ, Schindler M
JournalAnal Biochem
PubMed ID10610683
'A microtechnique has been developed that is capable of measuring the viscosity of filamentous actin (F-actin) solutions. This method, called optical displacement microviscometry (ODM), was utilized to determine the changes in viscosity of solutions of rabbit muscle, human platelet, and maize pollen actin when measured in the absence and presence ... More
Biophysical properties and microfilament assembly in neutrophils: modulation by cyclic AMP.
AuthorsDowney GP, Elson EL, Schwab B, Erzurum SC, Young SK, Worthen GS
JournalJ Cell Biol
PubMed ID1716633
'The microfilament lattice, composed primarily of filamentous (F)-actin, determines in large part the mechanical (deformability) properties of neutrophils, and thus may regulate the ability of neutrophils to transit a microvascular bed. Circulating factors may stimulate the neutrophil to become rigid and therefore be retained in the capillaries. We hypothesized that ... More
Thrombospondin signaling of focal adhesion disassembly requires activation of phosphoinositide 3-kinase.
AuthorsGreenwood JA, Pallero MA, Theibert AB, Murphy-Ullrich JE
JournalJ Biol Chem
PubMed ID9430723
'Thrombospondin is an extracellular matrix protein involved in modulating cell adhesion. Thrombospondin stimulates a rapid loss of focal adhesion plaques and reorganization of the actin cytoskeleton in cultured bovine aortic endothelial cells. The focal adhesion labilizing activity of thrombospondin is localized to the amino-terminal domain, specifically amino acids 17-35. Use ... More
Regional crypt function in rat large intestine in relation to fluid absorption and growth of the pericryptal sheath.
AuthorsNaftalin RJ, Pedley KC
JournalJ Physiol
PubMed ID9831728
'1. Confocal microscopic studies of rat colonic mucosa showed that the pericryptal sheath surrounding distal colonic crypts is an effective barrier both to dextran and NaCl movement, whereas no such structure surrounds the caecal crypts. 2. The distal colonic pericryptal barrier was functionally demonstrated by accumulation of Sodium Green within ... More
Focal loss of actin bundles causes microtubule redistribution and growth cone turning.
AuthorsZhou FQ, Waterman-Storer CM, Cohan CS
JournalJ Cell Biol
PubMed ID12034775
'It is commonly believed that growth cone turning during pathfinding is initiated by reorganization of actin filaments in response to guidance cues, which then affects microtubule structure to complete the turning process. However, a major unanswered question is how changes in actin cytoskeleton are induced by guidance cues and how ... More
Stimulation of cortical actin polymerization in the sea urchin egg cortex by NH4Cl, procaine and urethane: elevation of cytoplasmic pH is not the common mechanism of action.
AuthorsBegg DA, Wong GK, Hoyle DH, Baltz JM
JournalCell Motil Cytoskeleton
PubMed ID8913642
'Previous studies have demonstrated that the penetrating weak base NH4Cl and the anesthetics procaine and urethane disrupt the normal attachment of cortical granules to the cortex of the sea urchin egg. Hylander and Summers (1981: Dev. Biol. 86:1-11) hypothesized that this effect may be caused by a pH-induced polymerization of ... More
Tyrosine phosphorylation of the gamma subunit of Fc gamma receptors, p72syk, and paxillin during Fc receptor-mediated phagocytosis in macrophages.
AuthorsGreenberg S, Chang P, Silverstein SC
JournalJ Biol Chem
PubMed ID7508923
'Fc receptor-mediated phagocytosis in mouse macrophages occurs by a tyrosine kinase-dependent pathway (Greenberg, S., Chang, P., and Silverstein, S.C. (1993) J. Exp. Med. 177, 529-534). To identify proteins that are phosphorylated on tyrosine residues during phagocytosis, we used anti-phosphotyrosine antibodies to perform immunoblotting and immunoprecipitation of lysates derived from Fc ... More
F-actin content and spatial distribution in resting and chemoattractant-stimulated human polymorphonuclear leucocytes. Which role for intracellular free calcium?
AuthorsZaffran Y, Lepidi H, Bongrand P, Mege JL, Capo C
JournalJ Cell Sci
PubMed ID8408295
'Intracellular free calcium concentration ([Ca2+]i) plays a pivotal role for many responses in polymorphonuclear leucocytes (PMNs) stimulated by chemoattractants such as N-formylmethionyl-leucyl-phenylalanine (fMet-Leu-Phe). The importance of [Ca2+]i in the morphological polarization was investigated by using calcium-manipulated PMNs. We loaded human PMNs with BAPTA/AM to buffer or chelate [Ca2+]i in the ... More
Morphological polarization of human polymorphonuclear leucocytes in response to three different chemoattractants: an effector response independent of calcium rise and tyrosine kinases.
AuthorsLepidi H, Zaffran Y, Ansaldi JL, Mege JL, Capo C
JournalJ Cell Sci
PubMed ID7615691
'Chemoattractants such as interleukin-8, C5a and N-formylmethionyl-leucyl-phenylalanine induce a cytosolic calcium rise involved in triggering the secretory functions of human polymorphonuclear leucocytes. We studied the possible role of calcium rise in membrane ruffling, actin polymerization, filamentous actin distribution, and morphological polarization, which are all events contributing to chemotaxis. Membrane ruffling ... More
Change in expression of heart carnitine palmitoyltransferase I isoforms with electrical stimulation of cultured rat neonatal cardiac myocytes.
AuthorsXia Y, Buja LM, McMillin JB
JournalJ Biol Chem
PubMed ID8662650
'Electrical stimulation of neonatal rat cardiac myocytes in culture produces increases in myocyte size (hypertrophy) and organization of actin into myofibrillar arrays. The maturation of the cells is associated with enhanced contractile parameters and cellular calcium content. The numbers and intensity of cellular mitochondrial profiles increase, as measured by scanning ... More
Electrical stimulation of neonatal cardiac myocytes activates the NFAT3 and GATA4 pathways and up-regulates the adenylosuccinate synthetase 1 gene.
AuthorsXia Y, McMillin JB, Lewis A, Moore M, Zhu WG, Williams RS, Kellems RE
JournalJ Biol Chem
PubMed ID10636885
'Electrically stimulated pacing of cultured cardiomyocytes serves as an experimentally convenient and physiologically relevant in vitro model of cardiac hypertrophy. Electrical pacing triggers a signaling cascade that results in the activation of the muscle-specific Adss1 gene and the repression of the nonmuscle Adss2 isoform. Activation of the Adss1 gene involves ... More
Spatial and temporal dissection of immediate and early events following cadherin-mediated epithelial cell adhesion.
AuthorsMcNeill H, Ryan TA, Smith SJ, Nelson WJ
JournalJ Cell Biol
PubMed ID8436592
'Cell-cell adhesion is at the top of a molecular cascade of protein interactions that leads to the remodeling of epithelial cell structure and function. The earliest events that initiate this cascade are poorly understood. Using high resolution differential interference contrast microscopy and retrospective immunohistochemistry, we observed that cell-cell contact in ... More
Phallacidin stains the kinetochore region in the mitotic spindle of the green algae Oedogonium spp.
AuthorsSampson K, Pickett-Heaps JD
JournalProtoplasma
PubMed ID11732308
'We found previously that in living cells of Oedogonium cardiacum and O. donnellii, mitosis is blocked by the drug cytochalasin D (CD). We now report on the staining observed in these spindles with fluorescently actin-labeling reagents, particularly Bodipy FL phallacidin. Normal mitotic cells exhibited spots of staining associated with chromosomes; ... More
Dual inhibition of focal adhesion kinase and epidermal growth factor receptor pathways cooperatively induces death receptor-mediated apoptosis in human breast cancer cells.
'The focal adhesion kinase (FAK) and epidermal growth factor receptor (EGFR) are protein-tyrosine kinases that are overexpressed and activated in human breast cancer. To determine the role of EGFR and FAK survival signaling in breast cancer, EGFR was stably overexpressed in BT474 breast cancer cells, and each signaling pathway was ... More
Antisense inhibition of glial S100 beta production results in alterations in cell morphology, cytoskeletal organization, and cell proliferation.
AuthorsSelinfreund RH, Barger SW, Welsh MJ, Van Eldik LJ
JournalJ Cell Biol
PubMed ID2229184
'The phenotypic effects of selectively decreasing the levels of S100 beta in cultured glial cells were analyzed. Two separate antisense approaches were utilized for inhibition of S100 beta production: analysis of clonal isolates of rat C6 glioma cells containing an S100 beta antisense gene under the control of a dexamethasone-inducible ... More
Practical confocal microscopy and the evaluation of system performance.
AuthorsZucker RM, Price OT
JournalMethods
PubMed ID10491274
'The laser scanning confocal microscope has enormous potential in many fields of biology. Currently there is a subjective nature in the assessment of a confocal microscope''s performance by primarily evaluating the system with a specific test slide provided by the user''s laboratory. To achieve better performance from the equipment, it ... More
State of actin filaments is changed by anoxia in cultured rat neocortical neurons.
AuthorsFriedman JE, Chow EJ, Haddad GG
JournalNeuroscience
PubMed ID9466451
'Cultured neocortical neurons respond rapidly to oxygen deprivation. Within minutes they demonstrate an increase in intracellular calcium and pronounced changes in their morphology. These changes include swelling, bleb formations, process retraction and a change in shape of the soma from pyramidal or ellipsoidal to round. Since the cytoskeleton is responsible ... More
Pointed-end capping by tropomodulin3 negatively regulates endothelial cell motility.
AuthorsFischer RS, Fritz-Six KL, Fowler VM
JournalJ Cell Biol
PubMed ID12707310
'Actin filament pointed-end dynamics are thought to play a critical role in cell motility, yet regulation of this process remains poorly understood. We describe here a previously uncharacterized tropomodulin (Tmod) isoform, Tmod3, which is widely expressed in human tissues and is present in human microvascular endothelial cells (HMEC-1). Tmod3 is ... More
Inhibition of infection of macrophages with Ehrlichia risticii by cytochalasins, monodansylcadaverine, and taxol.
AuthorsRikihisa Y, Zhang Y, Park J
JournalInfect Immun
PubMed ID7927796
'The requirement of functions of clathrin, microfilaments, and microtubules in binding, internalization, proliferation, and spreading of Ehrlichia risticii in macrophages was studied. Monodansylcadaverine (MDC), which inhibits clustering and internalization of the ligand-receptor complexes into clathrin-coated vesicles; cytochalasin B or D, which depolymerizes microfilaments; and taxol, which binds and stabilizes polymerized ... More
Delivery of membrane-impermeant fluorescent probes into living neural cell populations by lipotransfer.
AuthorsBarber K, Mala RR, Lambert MP, Qiu R, MacDonald RC, Klein WL
JournalNeurosci Lett
PubMed ID8710199
'Use of fluorescent probes to monitor f-actin in living cells typically relies on difficult microinjection procedures. The current work has developed cationic lipotransfer of membrane-impermeant probes as an alternative to microinjection. BODIPY FL-phallacidin, a fluorescent f-actin probe, was packaged into 40-50 nm cationic liposomes. Packaging, verified by gel filtration, enabled ... More
A quantitative assessment of F-actin content and distribution in untreated and butyric acid treated murine melanoma B16a tumour cells: a fluorescence image analysis study.
AuthorsPersky B, McGarvey T
JournalHistochem J
PubMed ID2074210
Image analysis of phallacidin, a fluorescent stoichiometric probe to F-actin, permitted the cytoskeletal-associated actin 'F-actin' to be visualized morphologically and to be divided into two groups, diffuse and filamentous. The filamentous actin group was categorized further into four subgroups according to the intensity of the phallacidin probe. F-actin groups and ... More
Phallotoxin and actin binding assay by fluorescence enhancement.
AuthorsHuang ZJ, Haugland RP, You WM, Haugland RP
JournalAnal Biochem
PubMed ID1595896
The fluorescence of five fluorophores conjugated to phallotoxins was found to be specifically enhanced upon binding to F-actin in a polymerizing buffer. Rhodamine phalloidin had the greatest fluorescence enhancement of ninefold. The fluorescence titration of rhodamine phalloidin by actin was shown to be consistent with stoichiometric binding. The fluorescence enhancement ... More
Mechanisms of quantum dot nanoparticle cellular uptake.
AuthorsZhang LW, Monteiro-Riviere NA,
JournalToxicol Sci
PubMed ID19414515
Due to the superior photoemission and photostability characteristics, quantum dots (QD) are novel tools in biological and medical applications. However, the toxicity and mechanism of QD uptake are poorly understood. QD nanoparticles with an emission wavelength of 655 nm are ellipsoid in shape and consist of a cadmium/selenide core with ... More
Heparin oligosaccharides that pass the blood-brain barrier inhibit beta-amyloid precursor protein secretion and heparin binding to beta-amyloid peptide.
AuthorsLeveugle B, Ding W, Laurence F, Dehouck MP, Scanameo A, Cecchelli R, Fillit H
JournalJ Neurochem
PubMed ID9453569
We have previously demonstrated that full-length heparin stimulates the synthesis and secretion of beta-amyloid precursor protein (APP) through an amyloidogenic pathway in neuroblastoma cells. In the present study, heparin was chemically depolymerized, and the effect of low-molecular-weight (LMW) heparin on APP secretion was investigated. In contrast to full-length heparin, LMW ... More
Mammalian target of rapamycin and protein kinase A signaling mediate the cardiac transcriptional response to glutamine.
AuthorsXia Y, Wen HY, Young ME, Guthrie PH, Taegtmeyer H, Kellems RE
JournalJ Biol Chem
PubMed ID12522136
The addition of glutamine as a major nutrient to cultured neonatal rat cardiomyocytes produced an increase in myocyte size and the organization of actin into myofibrillar arrays. The cellular response was associated with increased abundance of the mRNAs encoding the contractile proteins, alpha-myosin heavy chain and cardiac alpha-actin, and the ... More
Microtubule retraction into the uropod and its role in T cell polarization and motility.
AuthorsRatner S, Sherrod WS, Lichlyter D
JournalJ Immunol
PubMed ID9233597
Spherical circulating T cells must polarize to extravasate. We have found that the polarization process includes a drastic reconfiguration of the tubulin cytoskeleton. In spherical T cells, the nucleus is surrounded by microtubules radiating from the microtubule organizing center (MTOC). During polarization the uropod (a slender posterior appendage) forms at ... More
How an actin network might cause fountain streaming and nuclear migration in the syncytial Drosophila embryo.
Authorsvon Dassow G, Schubiger G
JournalJ Cell Biol
PubMed ID7798318
We show here using time-lapse video tapes that cytoplasmic streaming causes nuclear migration along the anterior-posterior axis (axial expansion) in the early syncytial embryo of Drosophila melanogaster. Using confocal microscopy and labeled phalloidin we explore the distribution of F-actin during axial expansion. We find that a network of F-actin fibers ... More
Dual-colour microscopy of single fluorophores bound to myosin interacting with fluorescently labelled actin using anti-Stokes fluorescence.
AuthorsSaito K, Tokunaga M, Iwane AH, Yanagida T
JournalJ Microsc
PubMed ID9450329
We have refined prismless total internal reflection fluorescence microscopy with extremely low background to visualize single fluorophores attached to protein molecules interacting with a filamentous biopolymer labelled with different colour fluorophores. By using Stokes and anti-Stokes fluorescence, two different colour fluorescences from two different colour fluorophores excited with a single ... More
IQGAP1, a Rac- and Cdc42-binding protein, directly binds and cross-links microfilaments.
Activated forms of the GTPases, Rac and Cdc42, are known to stimulate formation of microfilament-rich lamellipodia and filopodia, respectively, but the underlying mechanisms have remained obscure. We now report the purification and characterization of a protein, IQGAP1, which is likely to mediate effects of these GTPases on microfilaments. Native IQGAP1 ... More
Identification and characterization of mutations in Ha-Ras that selectively decrease binding to cRaf-1.
AuthorsWinkler DG, Johnson JC, Cooper JA, Vojtek AB
JournalJ Biol Chem
PubMed ID9305899
The oncoprotein Ras transforms cells by binding to one or more effector proteins. Effector proteins have been identified by their ability to bind to Ras in the GTP but not GDP form, and by their requirement for the Ras effector domain for binding. The best understood Ras effectors are serine/threonine ... More
Vascular changes play a role in the pathogenesis of necrotizing enterocolitis in asphyxiated newborn pigs.
AuthorsGellén B, Kovács J, Németh L, Németh P, Vágvölgyi J, Bari F, Megyeri P, Pintér S, Temesvári P, Deli MA, Vecsernyés M, Szilvássy Z, Koltai M, Abrahám CS
JournalPediatr Surg Int
PubMed ID12756598
Necrotizing enterocolitis (NEC) is the most common acquired gastrointestinal emergency in neonates. We have developed an animal model of NEC in asphyxiated newborn pigs and investigated the effects of asphyxia on blood flow in superior mesenteric artery and abdominal aorta, cardiovascular data, arterial acid-base and blood gas parameters, and endothelial ... More
Central to the pathogenesis of atherosclerosis is an abnormally functioning endothelium and a consequent loss of vascular integrity. These abnormalities may be induced by haemodynamic factors, biochemical substances, and also by oxidatively modified low-density lipoprotein (LDL). To understand the mechanism by which oxidized LDL causes endothelial dysfunction, human umbilical vein ... More
Fission yeast Pob1p, which is homologous to budding yeast Boi proteins and exhibits subcellular localization close to actin patches, is essential for cell elongation and separation.
AuthorsToya M, Iino Y, Yamamoto M
JournalMol Biol Cell
PubMed ID10436025
The fission yeast pob1 gene encodes a protein of 871 amino acids carrying an SH3 domain, a SAM domain, and a PH domain. Gene disruption and construction of a temperature-sensitive pob1 mutant indicated that pob1 is essential for cell growth. Loss of its function leads to quick cessation of cellular ... More
Measurement of thin filament lengths by distributed deconvolution analysis of fluorescence images.
AuthorsLittlefield R, Fowler VM
JournalBiophys J
PubMed ID11964243
The lengths of the actin (thin) filaments in sarcomeres directly influence the physiological properties of striated muscle. Although electron microscopy techniques provide the highest precision and accuracy for measuring thin filament lengths, significant obstacles limit their widespread use. Here, we describe distributed deconvolution, a fluorescence-based method that determines the location ... More
Induction of atrial natriuretic factor and myosin light chain-2 gene expression in cultured ventricular myocytes by electrical stimulation of contraction.
AuthorsMcDonough PM, Glembotski CC
JournalJ Biol Chem
PubMed ID1376309
While hormonal stimuli and mechanical stretch can induced cardiac-specific gene expression and in some cases cellular hypertrophy, the relationship between myocyte contraction frequency, gene expression, and myocyte growth has not been well characterized. In this study a new model system was developed in which cultures of neonatal rat ventricular myocytes ... More
Thin filaments elongate from their pointed ends during myofibril assembly in Drosophila indirect flight muscle.
AuthorsMardahl-Dumesnil M, Fowler VM
JournalJ Cell Biol
PubMed ID11739412
Tropomodulin (Tmod) is an actin pointed-end capping protein that regulates actin dynamics at thin filament pointed ends in striated muscle. Although pointed-end capping by Tmod controls thin filament lengths in assembled myofibrils, its role in length specification during de novo myofibril assembly is not established. We used the Drosophila Tmod ... More
Growth cone collapse through coincident loss of actin bundles and leading edge actin without actin depolymerization.
AuthorsZhou FQ, Cohan CS
JournalJ Cell Biol
PubMed ID11381091
Repulsive guidance cues can either collapse the whole growth cone to arrest neurite outgrowth or cause asymmetric collapse leading to growth cone turning. How signals from repulsive cues are translated by growth cones into this morphological change through rearranging the cytoskeleton is unclear. We examined three factors that are able ... More
MMM1 encodes a mitochondrial outer membrane protein essential for establishing and maintaining the structure of yeast mitochondria.
AuthorsBurgess SM, Delannoy M, Jensen RE
JournalJ Cell Biol
PubMed ID8089172
In the yeast Saccharomyces cerevisiae, mitochondria are elongated organelles which form a reticulum around the cell periphery. To determine the mechanism by which mitochondrial shape is established and maintained, we screened yeast mutants for those defective in mitochondrial morphology. One of these mutants, mmm1, is temperature-sensitive for the external shape ... More
Drosophila paramyosin/miniparamyosin gene products show a large diversity in quantity, localization, and isoform pattern: a possible role in muscle maturation and function.
AuthorsMaroto M, Arredondo J, Goulding D, Marco R, Bullard B, Cervera M
JournalJ Cell Biol
PubMed ID8698824
The Drosophila paramyosin/miniparamyosin gene expresses two products of different molecular weight transcriptionally regulated from two different promoters. Distinct muscle types also have different relative amounts of myosin, paramyosin, and miniparamyosin, reflecting differences in the organization of their thick filaments. Immunofluorescence and EM data indicate that miniparamyosin is mainly located in ... More
Identification of a novel tropomodulin isoform, skeletal tropomodulin, that caps actin filament pointed ends in fast skeletal muscle.
AuthorsAlmenar-Queralt A, Lee A, Conley CA, Ribas de Pouplana L, Fowler VM
JournalJ Biol Chem
PubMed ID10497209
Tropomodulin (E-Tmod) is an actin filament pointed end capping protein that maintains the length of the sarcomeric actin filaments in striated muscle. Here, we describe the identification and characterization of a novel tropomodulin isoform, skeletal tropomodulin (Sk-Tmod) from chickens. Sk-Tmod is 62% identical in amino acid sequence to the previously ... More
Phosphorylation of ADF/cofilin abolishes EGF-induced actin nucleation at the leading edge and subsequent lamellipod extension.
AuthorsZebda N, Bernard O, Bailly M, Welti S, Lawrence DS, Condeelis JS
JournalJ Cell Biol
PubMed ID11086013
In metastatic rat mammary adenocarcinoma cells, cell motility can be induced by epidermal growth factor. One of the early events in this process is the massive generation of actin barbed ends, which elongate to form filaments immediately adjacent to the plasma membrane at the tip of the leading edge. As ... More
Gelatinase A activation is regulated by the organization of the polymerized actin cytoskeleton.
AuthorsTomasek JJ, Halliday NL, Updike DL, Ahern-Moore JS, Vu TK, Liu RW, Howard EW
JournalJ Biol Chem
PubMed ID9054450
Gelatinase A (GL-A) is a matrix metalloproteinase (MMP) involved in both connective tissue remodeling and tumor invasion. GL-A activation is mediated by a membrane-type MMP (MT-MMP) that cleaves the GL-A propeptide. In this study, we examined the role of the actin cytoskeleton in regulating GL-A activation and MT-MMP-1 expression. Human ... More
Armadillo is required for adherens junction assembly, cell polarity, and morphogenesis during Drosophila embryogenesis.
AuthorsCox RT, Kirkpatrick C, Peifer M
JournalJ Cell Biol
PubMed ID8698810
Morphological and biochemical analyses have identified a set of proteins which together form a structure known as the adherens junction. Elegant experiments in tissue culture support the idea that adherens junctions play a key role in cell-cell adhesion and in organizing cells into epithelia. During normal embryonic development, cells quickly ... More
Vimentin dephosphorylation by protein phosphatase 2A is modulated by the targeting subunit B55.
AuthorsTurowski P, Myles T, Hemmings BA, Fernandez A, Lamb NJ
JournalMol Biol Cell
PubMed ID10359611
The intermediate filament protein vimentin is a major phosphoprotein in mammalian fibroblasts, and reversible phosphorylation plays a key role in its dynamic rearrangement. Selective inhibition of type 2A but not type 1 protein phosphatases led to hyperphosphorylation and concomitant disassembly of vimentin, characterized by a collapse into bundles around the ... More
Profilin is predominantly associated with monomeric actin in Acanthamoeba.
AuthorsKaiser DA, Vinson VK, Murphy DB, Pollard TD
JournalJ Cell Sci
PubMed ID10523513
We used biochemical fractionation, immunoassays and microscopy of live and fixed Acanthamoeba to determine how much profilin is bound to its known ligands: actin, membrane PIP(2), Arp2/3 complex and polyproline sequences. Virtually all profilin is soluble after gentle homogenization of cells. During gel filtration of extracts on Sephadex G75, approximately ... More
Calbindin expression in renal tubular epithelial cells. Altered sodium phosphate co-transport in association with cytoskeletal rearrangement.
AuthorsPollock AS, Santiesteban HL
JournalJ Biol Chem
PubMed ID7541797
Sodium-phosphate transport in the opossum kidney (OK) cell line was studied in an OK clonal cell line that was transfected with an episomal vector expressing high levels of rat calbindin (28 kDa). High level expression of calbindin buffered the influx of calcium induced by ionomycin by 53% and raised the ... More
Passive mechanical behavior of human neutrophils: effects of colchicine and paclitaxel.
AuthorsTsai MA, Waugh RE, Keng PC
JournalBiophys J
PubMed ID9635782
The role of microtubules in determining the mechanical rigidity of neutrophils was assessed. Neutrophils were treated with colchicine to disrupt microtubules, or with paclitaxel to promote formation of microtubules. Paclitaxel caused an increase in the number of microtubules in the cells as assessed by immunofluorescence, but it had no effect ... More
Properties of filament-bound myosin light chain kinase.
AuthorsLin P, Luby-Phelps K, Stull JT
JournalJ Biol Chem
PubMed ID10026225
Myosin light chain kinase binds to actin-containing filaments from cells with a greater affinity than to F-actin. However, it is not known if this binding in cells is regulated by Ca2+/calmodulin as it is with F-actin. Therefore, the binding properties of the kinase to stress fibers were examined in smooth ... More
Mechanically stimulated cytoskeleton rearrangement and cortical contraction in human neutrophils.
AuthorsZhelev DV, Hochmuth RM
JournalBiophys J
PubMed ID7612842
A mechanical test with micropipets is used to characterize cytoskeleton rearrangement and contraction induced by mechanical stresses in human neutrophils. The yield shear resultant of the cell cortex is on the order of 0.06 to 0.09 mN.m-1. The measured yield shear resultant suggests that the neutrophil cortex is a weakly ... More
Axotomy-induced axonal degeneration is mediated by calcium influx through ion-specific channels.
AuthorsGeorge EB, Glass JD, Griffin JW
JournalJ Neurosci
PubMed ID7472407
We examined the role of extracellular calcium entry, the possible involvement of axonal calcium channels, and the potential protective effect of calcium channel and calpain antagonists in axotomy-induced axonal degeneration using murine dorsal root ganglia in cell culture. We found that calcium entry is both necessary and sufficient to induce ... More
Cortical and cytoplasmic flow polarity in early embryonic cells of Caenorhabditis elegans.
AuthorsHird SN, White JG
JournalJ Cell Biol
PubMed ID8509454
We have examined the cortex of Caenorhabditis elegans eggs during pseudocleavage (PC), a period of the first cell cycle which is important for the generation of asymmetry at first cleavage (Strome, S. 1989. Int. Rev. Cytol. 114: 81-123). We have found that directed, actin dependent, cytoplasmic, and cortical flow occurs ... More
Fc receptor-triggered insertion of secretory granules into the plasma membrane of human neutrophils: selective retrieval during phagocytosis.
AuthorsTapper H, Grinstein S
JournalJ Immunol
PubMed ID9200480
We studied the kinetics of secretion in human neutrophils stimulated by IgG-opsonized zymosan. Secretion of azurophilic and specific granules was quantified measuring the appearance of the granule markers CD63 and CD66b, respectively, at the cell surface. The kinetics of secretion was compared with the course of phagocytosis, revealed by the ... More
Vasoactive substances induce cytoskeletal changes in cultured rat glomerular epithelial cells.
AuthorsSharma R, Lovell HB, Wiegmann TB, Savin VJ
JournalJ Am Soc Nephrol
PubMed ID1336407
Angiotensin II (ANG II), atrial natriuretic peptide III (ANP), and sodium nitroprusside (SNP) alter capillary hydraulic conductivity in isolated glomeruli. These agents also affect cyclic nucleotide levels of glomerular epithelial cells (GEC). ANG II increases cAMP, whereas ANP and SNP increase cGMP. The effects of these vasoactive substances on GEC ... More
Cell membrane alignment along adhesive surfaces: contribution of active and passive cell processes.
AuthorsPierres A, Eymeric P, Baloche E, Touchard D, Benoliel AM, Bongrand P
JournalBiophys J
PubMed ID12609907
Cell adhesion requires nanometer scale membrane alignment to allow contact between adhesion receptors. Little quantitative information is presently available on this important biological process. Here we present an interference reflection microscopic study of the initial interaction between monocytic THP-1 cells and adhesive surfaces, with concomitant determination of cell deformability, using ... More
Quantitative image analysis of F-actin in endothelial cells.
AuthorsEhringer WD, Yamany S, Steier K, Farag A, Roisen FJ, Dozier A, Miller FN
JournalMicrocirculation
PubMed ID10654280
OBJECTIVE: Filamentous actin (F-actin) plays a central role in maintaining endothelial barrier function. Thrombin and histamine, two inflammatory mediators that increase endothelial permeability, can alter F-actin production and distribution. In this study, we use a newly developed image analysis technique to show that these two inflammatory mediators differentially alter F-actin ... More
The role of the cytoskeleton in cellular adhesion molecule expression in tumor necrosis factor-stimulated endothelial cells.
AuthorsVandenBerg E, Reid MD, Edwards JD, Davis HW
JournalJ Cell Biochem
PubMed ID15034928
Leukocyte infiltration is a hallmark of the atherosclerotic lesion. These cells are captured by cellular adhesion molecules (CAMs), including vascular cell adhesion molecule-1 (VCAM-1), intercellular adhesion molecule-1 (ICAM-1), platelet-endothelial cell adhesion molecule (PECAM), and E-selectin, on endothelial cells (EC). We examined the role of the actin cytoskeleton in tumor necrosis ... More
Alterations in the localization of F-actin, fibronectin, and thrombospondin occur prior to neoplastic transformation in rat tracheal epithelial cells.
AuthorsCarter CA, Doherty MM, Rusnak DW, Nettesheim P, Ferriola PC
JournalExp Cell Res
PubMed ID8174636
Structural glycoproteins and cytoskeletal proteins play a major role in the regulation of cellular organization and function. Changes in the structure and function of these proteins are involved in the cascade of events which lead to neoplastic transformation. We evaluated RNA levels, protein localization, and organization of selected proteins in ... More
Bradykinin antagonizes the effects of alpha-thrombin.
AuthorsEhringer WD, Edwards MJ, Gray RD, Miller FN
JournalInflammation
PubMed ID9246571
alpha-Thrombin (AT) and bradykinin (BK) are endogenous mediators that are released during an inflammatory response, and could have a synergistic effect on endothelial permeability. Human umbilical vein endothelial cells (HUVEC) were grown on Transwell membranes and then tested for alterations in permeability to fluorescein isothiocyanate-labeled human serum albumin. Addition of ... More
Tyrosine phosphorylation of pp125FAK in platelets requires coordinated signaling through integrin and agonist receptors.
FAK is a focal adhesion kinase that is phosphorylated on tyrosine in activated platelets. Induction of FAK phosphorylation requires both fibrinogen binding to integrin alpha IIb beta 3 and post-occupancy events during agonist-induced platelet aggregation or platelet spreading on a fibrinogen matrix. To identify the signaling pathways necessary for tyrosine ... More
Mechanisms of alpha-thrombin, histamine, and bradykinin induced endothelial permeability.
AuthorsEhringer WD, Edwards MJ, Miller FN
JournalJ Cell Physiol
PubMed ID8655610
alpha-Thrombin, bradykinin, and histamine are endogenous mediators that increase endothelial permeability. We examined the mechanism by which these three vasoactive mediators could alter permeability to albumin of human umbilical vein endothelial cells (HUVEC). HUVEC were grown to confluence on Transwell membranes and we monitored the flux of fluorescein isothiocyanate-labeled human ... More
Recognition of two classes of oligoproline sequences in profilin-mediated acceleration of actin-based Shigella motility.
AuthorsZeile WL, Purich DL, Southwick FS
JournalJ Cell Biol
PubMed ID8601612
The gram negative rod Shigella flexneri uses it surface protein IcsA to induce host cell actin assembly and to achieve intracellular motility. Yet, the IcsA protein lacks the oligoproline sequences found in ActA, the surface protein required for locomotion of the gram positive rod Listeria monocytogenes. Microinjection of a peptide ... More
Overexpression of the dynamitin (p50) subunit of the dynactin complex disrupts dynein-dependent maintenance of membrane organelle distribution.
Dynactin is a multisubunit complex that plays an accessory role in cytoplasmic dynein function. Overexpression in mammalian cells of one dynactin subunit, dynamitin, disrupts the complex, resulting in dissociation of cytoplasmic dynein from prometaphase kinetochores, with consequent perturbation of mitosis (Echeverri, C.J., B.M. Paschal, K.T. Vaughan, and R.B. Vallee. 1996. ... More
Gelsolin, a protein that caps the barbed ends and severs actin filaments, enhances the actin-based motility of Listeria monocytogenes in host cells.
The actin-based motility of Listeria monocytogenes requires the addition of actin monomers to the barbed or plus ends of actin filaments. Immunofluorescence micrographs have demonstrated that gelsolin, a protein that both caps barbed ends and severs actin filaments, is concentrated directly behind motile bacteria at the junction between the actin ... More
Adenosine inhibits actin dynamics in human neutrophils: evidence for the involvement of cAMP.
AuthorsZalavary S, Bengtsson T
JournalEur J Cell Biol
PubMed ID9548370
The mechanisms by which adenosine regulates the inflammatory reaction are poorly characterized. In this study, we investigated the effects of adenosine on neutrophil actin polymerization elicited by the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine (fMLP) or IgG-opsonized yeast particles. We used bodipy-phallacidin staining in combination with flow cytometry and found that adenosine markedly ... More
A role for phosphatidylinositol 3-kinase in the regulation of beta 1 integrin activity by the CD2 antigen.
AuthorsShimizu Y, Mobley JL, Finkelstein LD, Chan AS
JournalJ Cell Biol
PubMed ID8557753
The rapid and reversible upregulation of the functional activity of integrin receptors on T lymphocytes is a vital step in the adhesive interactions that occur during successful T cell recognition of foreign antigen and transendothelial migration. Although the ligation of several different cell surface receptors, including the antigen-specific CD3/T cell ... More
Changes in cytoskeletal actin content, F-actin distribution, and surface morphology during HL-60 cell volume regulation.
AuthorsHallows KR, Law FY, Packman CH, Knauf PA
JournalJ Cell Physiol
PubMed ID8698841
Cell volume regulation occurs via the regulated fluxes of ions and solutes across the cell membrane in response to cell volume perturbations under anisotonic conditions. Our earlier studies in human promyelocytic leukemic HL-60 cells showed that volume-dependent changes in total cellular F-actin content occur concomitantly as an inverse function of ... More
Evaluation of confocal microscopy system performance.
AuthorsZucker RM, Price O
JournalCytometry
PubMed ID11500845
BACKGROUND: The confocal laser scanning microscope (CLSM) has been used by scientists to visualize three-dimensional (3D) biological samples. Although this system involves lasers, electronics, optics, and microscopes, there are few published tests that can be used to assess the performance of this equipment. Usually the CLSM is assessed by subjectively ... More
Heparin-binding peptides from thrombospondins 1 and 2 contain focal adhesion-labilizing activity.
AuthorsMurphy-Ullrich JE, Gurusiddappa S, Frazier WA, Höök M
JournalJ Biol Chem
PubMed ID8253815
The cell adhesion regulating extracellular matrix glycoprotein, thrombospondin (TSP), causes a loss of focal adhesion plaques from spread endothelial cells and fibroblasts. To localize the site on TSP that has focal adhesion-labilizing activity, we initially tested proteolytic fragments of TSP for activity. The heparin-binding fragment has significant focal adhesion-labilizing activity, ... More
Distinct effects of Rac1 on differentiation of primary avian myoblasts.
AuthorsGallo R, Serafini M, Castellani L, Falcone G, Alemà S
JournalMol Biol Cell
PubMed ID10512856
Rho family GTPases have been implicated in the regulation of the actin cytoskeleton in response to extracellular cues and in the transduction of signals from the membrane to the nucleus. Their role in development and cell differentiation, however, is little understood. Here we show that the transient expression of constitutively ... More
Recycling pathways of glucosylceramide in BHK cells: distinct involvement of early and late endosomes.
AuthorsKok JW, Hoekstra K, Eskelinen S, Hoekstra D
JournalJ Cell Sci
PubMed ID1487494
Recycling pathways of the sphingolipid glucosylceramide were studied by employing a fluorescent analog of glucosylceramide, 6(-)[N-(7-nitro-2,1,3-benzoxadiazol-4-yl)amino]hexanoylglucosyl sphingosine (C6-NBD-glucosylceramide). Direct recycling of the glycolipid from early endosomes to the plasma membrane occurs, as could be shown after treating the cells with the microtubule-disrupting agent nocodazole, which causes inhibition of the glycolipid's ... More
G protein-coupled receptor/arrestin3 modulation of the endocytic machinery.
AuthorsSantini F, Gaidarov I, Keen JH
JournalJ Cell Biol
PubMed ID11839771
Nonvisual arrestins (arr) modulate G protein-coupled receptor (GPCR) desensitization and internalization and bind to both clathrin (CL) and AP-2 components of the endocytic coated pit (CP). This raises the possibility that endocytosis of some GPCRs may be a consequence of arr-induced de novo CP formation. To directly test this hypothesis, ... More
Non-sarcomeric mode of myosin II organization in the fibroblast lamellum.
AuthorsVerkhovsky AB, Borisy GG
JournalJ Cell Biol
PubMed ID8227130
The organization of myosin in the fibroblast lamellum was studied by correlative fluorescence and electron microscopy after a novel procedure to reveal its underlying morphology. An X-rhodamine analog of conventional smooth muscle myosin (myosin II) that colocalized after microinjection with endogenous myosin was used to trace myosin distribution in living ... More
Microfilament reorganization is associated with functional activation of alpha M beta 2 on monocytic cells.
AuthorsElemer GS, Edgington TS
JournalJ Biol Chem
PubMed ID7508910
Selected agonists convert the leukocyte integrin alpha M beta 2 on monocytes from a low to a high affinity state competent to bind factor X and fibrinogen. Conformational changes of alpha M beta 2 re hypothesized to account for this functional transition. Here we report that cytochalasins known to interfere ... More
Non-contractile cells with thin processes resembling interstitial cells of Cajal found in the wall of guinea-pig mesenteric arteries.
AuthorsPucovský V, Moss RF, Bolton TB
JournalJ Physiol
PubMed ID12897177
Arterial interstitial cells of Cajal (ICC)-like cells (AIL cells) with a multipolar, irregular, elongated shape and with numerous thin (often less than 1 microm), sometimes branching, processes with lengths up to approximately 60 microm were isolated enzymatically from 1st to 7th order branches of guinea-pig mesenteric artery. Some of the ... More
The invasin protein of Yersinia enterocolitica: internalization of invasin-bearing bacteria by eukaryotic cells is associated with reorganization of the cytoskeleton.
AuthorsYoung VB, Falkow S, Schoolnik GK
JournalJ Cell Biol
PubMed ID1730744
Yersinia enterocolitica, a facultative intracellular pathogen of mammals, readily enters (i.e., invades) cultured eukaryotic cells, a process that can be conferred by the cloned inv locus of the species. We have studied the mechanism by which the product of inv, a microbial outer membrane protein termed "invasin," mediates the internalization ... More
Inhibition of the calcium-dependent tyrosine kinase (CADTK) blocks monocyte spreading and motility.
Freshly isolated peripheral blood monocytes lack focal adhesion kinase (p125(FAK)) but activate a second member of this kinase family, calcium-dependent tyrosine kinase (CADTK; also known as Pyk2/CAKbeta/RAFTK/FAK2), upon adhesion or stimulation with chemokines. To study the role of CADTK in monocyte adherence and motility, we performed immunocytochemical localization that showed ... More
Subcellular localization and possible function of actin, tropomyosin and actin-related protein 3 (Arp3) in the fission yeast Schizosaccharomyces pombe.
AuthorsArai R, Nakano K, Mabuchi I
JournalEur J Cell Biol
PubMed ID9765059
We investigated subcellular localizations and interactions of actin and two actin cytoskeleton-related proteins, Cdc8 tropomyosin and actin-related protein 3, Arp3, in the fission yeast Schizosaccharomyces pombe, using specific antibodies and by gene disruption. Actin was localized to the medial microfilamentous ring in the region of the septum during cytokinesis and ... More
Inhibition of Listeria locomotion by mosquito oostatic factor, a natural oligoproline peptide uncoupler of profilin action.
AuthorsSouthwick FS, Purich DL
JournalInfect Immun
PubMed ID7806356
Mosquito oostatic factor, a naturally occurring decapeptide (YDPAPPPPPP), strikingly resembles the primary structure of oligoproline-rich regions within the protein ActA, a bacterial surface protein required for Listeria motility in host cells. When microinjected into Listeria-infected PtK2 cells, the insect oostatic factor rapidly blocks Listeria-induced actin rocket tail assembly as well ... More
Stimulation of beta1 integrins on fibroblasts induces PDGF independent tyrosine phosphorylation of PDGF beta-receptors.
AuthorsSundberg C, Rubin K
JournalJ Cell Biol
PubMed ID8647902
We report that integrin-mediated signaling induces a rapid and transient tyrosine phosphorylation of platelet-derived growth factor (PDGF) beta-receptors in human diploid foreskin AG 1518 fibroblasts. A transient tyrosine phosphorylation of PDGF beta-receptors was evident one and two hours after cells had been plated on collagen type I and fibronectin, as ... More
Dynamics of filamentous actin organization in the sea urchin egg cortex during early cleavage divisions: implications for the mechanism of cytokinesis.
AuthorsWong GK, Allen PG, Begg DA
JournalCell Motil Cytoskeleton
PubMed ID8986375
We have used confocal laser scanning microscopy in conjunction with BODIPY-phallacidin staining of filamentous actin to investigate changes in the quantity and organization of cortical actin during the first two cell cycles following fertilization in eggs of the sea urchin Strongylocentrotus purpuratus. Quantification of fluorescent phallacidin staining reveals that the ... More
Changes in F-actin organization induced by hard metal particle exposure in rat pulmonary epithelial cells using laser scanning confocal microscopy.
AuthorsAntonini JM, Starks K, Roberts JR, Millecchia L, Yang HM, Rao KM
JournalIn Vitr Mol Toxicol
PubMed ID10900403
Chronic inhalation of hard metal (WC-Co) particles causes alveolitis and the eventual development of pulmonary fibrosis. The initial inflammatory response includes a change in the alveolar epithelial cell-capillary barrier, which has been shown to be regulated by the state of assembly and organization of the actin cytoskeletal network. The objective ... More
Alteration of cell cycle timing and induction of surface instability in starfish blastomeres microinjected with antibodies to spectrin.
AuthorsWong GK, Hoyle DH, Begg DA
JournalDev Biol
PubMed ID8948585
Spectrin has been implicated in a variety of different processes during late embryogenesis, after transcription of the zygotic genome has been activated. However, relatively little is known about the role of maternally derived spectrin during the early cleavage divisions that give rise to a multicellular embryo. To investigate the role ... More
Evidence for functional differentiation among Drosophila septins in cytokinesis and cellularization.
AuthorsAdam JC, Pringle JR, Peifer M
JournalMol Biol Cell
PubMed ID10982405
The septins are a conserved family of proteins that are involved in cytokinesis and other aspects of cell-surface organization. In Drosophila melanogaster, null mutations in the pnut septin gene are recessive lethal, but homozygous pnut mutants complete embryogenesis and survive until the pupal stage. Because the completion of cellularization and ... More
The Chlamydomonas mating type plus fertilization tubule, a prototypic cell fusion organelle: isolation, characterization, and in vitro adhesion to mating type minus gametes.
AuthorsWilson NF, Foglesong MJ, Snell WJ
JournalJ Cell Biol
PubMed ID9199169
In the biflagellated alga Chlamydomonas, adhesion and fusion of the plasma membranes of gametes during fertilization occurs via an actin-filled, microvillus-like cell protrusion. Formation of this approximately 3-microm-long fusion organelle, the Chlamydomonas fertilization tubule, is induced in mating type plus (mt+) gametes during flagellar adhesion with mating type minus (mt-) ... More