Selective cell targeting with light-absorbing microparticles and nanoparticles.
AuthorsPitsillides CM, Joe EK, Wei X, Anderson RR, Lin CP
JournalBiophys J
PubMed ID12770906
'We describe a new method for selective cell targeting based on the use of light-absorbing microparticles and nanoparticles that are heated by short laser pulses to create highly localized cell damage. The method is closely related to chromophore-assisted laser inactivation and photodynamic therapy, but is driven solely by light absorption, ... More
GPCR signaling is required for blood-brain barrier formation in drosophila.
AuthorsSchwabe T, Bainton RJ, Fetter RD, Heberlein U, Gaul U,
JournalCell
PubMed ID16213218
'The blood-brain barrier of Drosophila is established by surface glia, which ensheath the nerve cord and insulate it against the potassium-rich hemolymph by forming intercellular septate junctions. The mechanisms underlying the formation of this barrier remain obscure. Here, we show that the G protein-coupled receptor (GPCR) Moody, the G protein ... More
Plasma membrane repair is mediated by Ca(2+)-regulated exocytosis of lysosomes.
AuthorsReddy A, Caler EV, Andrews NW
JournalCell
PubMed ID11511344
'Plasma membrane wounds are repaired by a mechanism involving Ca(2+)-regulated exocytosis. Elevation in intracellular [Ca(2+)] triggers fusion of lysosomes with the plasma membrane, a process regulated by the lysosomal synaptotagmin isoform Syt VII. Here, we show that Ca(2+)-regulated exocytosis of lysosomes is required for the repair of plasma membrane disruptions. ... More
Nuclear import of insulin-like growth factor-binding protein-3 and -5 is mediated by the importin beta subunit.
AuthorsSchedlich LJ, Le Page SL, Firth SM, Briggs LJ, Jans DA, Baxter RC
JournalJ Biol Chem
PubMed ID10811646
'Although insulin-like growth factor-binding protein (IGFBP)-3 and IGFBP-5 are known to modulate cell growth by reversibly sequestering extracellular insulin-like growth factors, several reports have suggested that IGFBP-3, and possibly also IGFBP-5, have important insulin-like growth factor-independent effects on cell growth. These effects may be related to the putative nuclear actions ... More
Constitutive macropinocytosis in oncogene-transformed fibroblasts depends on sequential permanent activation of phosphoinositide 3-kinase and phospholipase C.
AuthorsAmyere M, Payrastre B, Krause U, Van Der Smissen P, Veithen A, Courtoy PJ
JournalMol Biol Cell
PubMed ID11029048
'Macropinocytosis results from the closure of lamellipodia generated by membrane ruffling, thereby reflecting cortical actin dynamics. Both transformation of Rat-1 fibroblasts by v-Src or K-Ras and stable transfection for expression of dominant-positive, wild-type phosphoinositide 3-kinase (PI3K) regulatory subunit p85 alpha constitutively led to stress fiber disruption, cortical actin recruitment, extensive ... More
Heterotrimeric kinesin II is the microtubule motor protein responsible for pigment dispersion in Xenopus melanophores.
AuthorsTuma MC, Zill A, Le Bot N, Vernos I, Gelfand V
JournalJ Cell Biol
PubMed ID9852150
'Melanophores move pigment organelles (melanosomes) from the cell center to the periphery and vice-versa. These bidirectional movements require cytoplasmic microtubules and microfilaments and depend on the function of microtubule motors and a myosin. Earlier we found that melanosomes purified from Xenopus melanophores contain the plus end microtubule motor kinesin II, ... More
Phorbol ester promotes endocytosis by activating a factor involved in endosome fusion.
AuthorsAballay A, Stahl PD, Mayorga LS
JournalJ Cell Sci
PubMed ID10393811
'Previous studies indicate that a zinc- and phorbol ester-binding factor is necessary for in vitro endosome fusion and for the effect of Rab5 on endosome fusion. Rab5 is a small GTPase that regulates membrane fusion between early endosomes derived from either receptor-mediated endocytosis or fluid-phase endocytosis. In its GTP-bound form, ... More
Heterotrimeric G protein subunits are located on rat liver endosomes.
AuthorsVan Dyke RW
JournalBMC Physiol
PubMed ID14711382
'BACKGROUND: Rat liver endosomes contain activated insulin receptors and downstream signal transduction molecules. We undertook these studies to determine whether endosomes also contain heterotrimeric G proteins that may be involved in signal transduction from G protein-coupled receptors. RESULTS: By Western blotting Gsalpha, Gialpha1,2, Gialpha3 and Gbeta were enriched in both ... More
Synaptotagmin VII regulates Ca(2+)-dependent exocytosis of lysosomes in fibroblasts.
'Synaptotagmins (Syts) are transmembrane proteins with two Ca(2+)-binding C(2) domains in their cytosolic region. Syt I, the most widely studied isoform, has been proposed to function as a Ca(2+) sensor in synaptic vesicle exocytosis. Several of the twelve known Syts are expressed primarily in brain, while a few are ubiquitous ... More
Elemental propagation of calcium signals in response-specific patterns determined by environmental stimulus strength.
AuthorsGoddard H, Manison NF, Tomos D, Brownlee C
JournalProc Natl Acad Sci U S A
PubMed ID10677557
'Plant cells can respond qualitatively and quantitatively to a wide range of environmental signals. Ca(2+) is used as an intracellular signal for volume regulation in response to external osmotic changes. We show here that the spatiotemporal patterns of hypo-osmotically induced Ca(2+) signals vary dramatically with stimulus strength in embryonic cells ... More
Presynaptic versus postsynaptic localization of mu and delta opioid receptors in dorsal and ventral striatopallidal pathways.
AuthorsOlive MF, Anton B, Micevych P, Evans CJ, Maidment NT
JournalJ Neurosci
PubMed ID9295393
'Parallel studies have demonstrated that enkephalin release from nerve terminals in the pallidum (globus pallidus and ventral pallidum) can be modulated by locally applied opioid drugs. To investigate further the mechanisms underlying these opioid effects, the present study examined the presynaptic and postsynaptic localization of delta (DOR1) and mu (MOR1) ... More
Bcl-xL functions downstream of caspase-8 to inhibit Fas- and tumor necrosis factor receptor 1-induced apoptosis of MCF7 breast carcinoma cells.
AuthorsSrinivasan A, Li F, Wong A, Kodandapani L, Smidt R, Krebs JF, Fritz LC, Wu JC, Tomaselli KJ
JournalJ Biol Chem
PubMed ID9468507
'Stimulation of the Fas or tumor necrosis factor receptor 1 (TNFR1) cell surface receptors leads to the activation of the death effector protease, caspase-8, and subsequent apoptosis. In some cells, Bcl-xL overexpression can inhibit anti-Fas- and tumor necrosis factor (TNF)-alpha-induced apoptosis. To address the effect of Bcl-xL on caspase-8 processing, ... More
A role for phosphoinositide 3-kinase in the completion of macropinocytosis and phagocytosis by macrophages.
AuthorsAraki N, Johnson MT, Swanson JA
JournalJ Cell Biol
PubMed ID8947549
'Phosphoinositide 3-kinase (PI 3-kinase) has been implicated in growth factor signal transduction and vesicular membrane traffic. It is thought to mediate the earliest steps leading from ligation of cell surface receptors to increased cell surface ruffling. We show here that inhibitors of PI 3-kinase inhibit endocytosis in macrophages, not by ... More
Regulation and intracellular trafficking pathways of the endothelin receptors.
AuthorsBremnes T, Paasche JD, Mehlum A, Sandberg C, Bremnes B, Attramadal H
JournalJ Biol Chem
PubMed ID10747877
'The effects of endothelin (ET) are mediated via the G protein-coupled receptors ET(A) and ET(B). However, the mechanisms of ET receptor desensitization, internalization, and intracellular trafficking are poorly understood. The aim of the present study was to investigate the molecular mechanisms of ET receptor regulation and to characterize the intracellular ... More
Mechanisms of integrin-mediated calcium signaling in MDCK cells: regulation of adhesion by IP3- and store-independent calcium influx.
AuthorsSjaastad MD, Lewis RS, Nelson WJ
JournalMol Biol Cell
PubMed ID8862518
'Peptides containing Arg-Gly-Asp (RGD) immobilized on beads bind to integrins and trigger biphasic, transient increases in intracellular free Ca2+ ([Ca2+]i) in Madin-Darby canine kidney epithelial cells. The [Ca2+]i increase participates in feedback regulation of integrin-mediated adhesion in these cells. We examined influx pathways and inositol 1,4,5-trisphosphate (IP3)-mediated Ca2+ store release ... More
Visually guided injection of identified reticulospinal neurons in zebrafish: a survey of spinal arborization patterns.
AuthorsGahtan E, O'Malley DM
JournalJ Comp Neurol
PubMed ID12640669
'We report here the pattern of axonal branching for 11 descending cell types in the larval brainstem; eight of these cell types are individually identified neurons. Large numbers of brainstem neurons were retrogradely labeled in living larvae by injecting Texas-red dextran into caudal spinal cord. Subsequently, in each larva a ... More
Activation of trypsinogen in large endocytic vacuoles of pancreatic acinar cells.
'The intracellular activation of trypsinogen, which is both pH- and calcium-dependent, is an important early step in the development of acute pancreatitis. The cellular compartment in which trypsinogen activation occurs currently is unknown. We therefore investigated the site of intracellular trypsinogen activation by using an established cellular model of acute ... More
Characterization of cellular optoporation with distance.
'We have developed and characterized cellular optoporation with visible wavelengths of light using standard uncoated glass cover slips as the absorptive media. A frequency-doubled Nd:YAG laser pulse was focused at the interface of the glass surface and aqueous buffer, creating a stress wave and transiently permeabilizing nearby cells. Following optoporation ... More
Involvement of stretch-sensitive calcium flux in mechanical transduction in visceral afferents.
AuthorsRaybould HE, Gschossman JM, Ennes H, Lembo T, Mayer EA
JournalJ Auton Nerv Syst
PubMed ID9935263
'The spinal and vagal visceral innervation to the gastrointestinal tract contains mechanosensitive afferents that are activated by contraction, distension of smooth muscle or movement in the receptive field. The mechanism by which free nerve endings detect changes in smooth muscle tension is not clear. The present study investigated the effects ... More
Pollen tubes exhibit regular periodic membrane trafficking events in the absence of apical extension.
'The growing pollen tube provides an excellent single cell model system in which to study the mechanisms determining growth regulation, polarity and periodic behaviour. Previously, using FM4-64, we identified periodic movements within the apical vesicle accumulation that were related to the period of oscillatory growth. This suggested a more complex ... More
Tumor necrosis factor-alpha-associated lysosomal permeabilization is cathepsin B dependent.
'Cathepsin B (Cat B) is released from lysososomes during tumor necrosis factor-alpha (TNF-alpha) cytotoxic signaling in hepatocytes and contributes to cell death. Sphingosine has recently been implicated in lysosomal permeabilization and is increased in the liver by TNF-alpha. Thus the aims of this study were to examine the mechanisms involved ... More
Insertion of MP20 into lens fibre cell plasma membranes correlates with the formation of an extracellular diffusion barrier.
'It is known that during lens differentiation a number of fibre cell specific membrane proteins change their expression profiles. In this study we have investigated how the profiles of the two most abundant fibre cell membrane proteins AQP0 (formerly known as Major Intrinsic Protein, MIP) and MP20 change as a ... More
Adenocarcinoma of the pancreas in childhood. Report of a case and a review of the English language literature.
AuthorsTaxy JB
JournalCancer
PubMed ID1260669
'A case of adenocarcinoma of the head of the pancreas in a 13-year-old girl is reported. Some areas simulated an islet cell tumor by light microscopy, but contained numerous eosinophilic granules which were PAS-positive and diastase resistant. Ultrastructurally, the granules were large (960 mum-3000 mum in diameter) and electron-dense, resembling ... More
Analysis of retrograde transport in motor neurons reveals common endocytic carriers for tetanus toxin and neurotrophin receptor p75NTR.
AuthorsLalli G, Schiavo G
JournalJ Cell Biol
PubMed ID11807088
'Axonal retrograde transport is essential for neuronal growth and survival. However, the nature and dynamics of the membrane compartments involved in this process are poorly characterized. To shed light on this pathway, we established an experimental system for the visualization and the quantitative study of retrograde transport in living motor ... More
Reduced endocytosis and altered lysosome function in cisplatin-resistant cell lines.
AuthorsChauhan SS, Liang XJ, Su AW, Pai-Panandiker A, Shen DW, Hanover JA, Gottesman MM
JournalBr J Cancer
PubMed ID12698203
'We isolated human KB adenocarcinoma cisplatin-resistant (CP-r) cell lines with multidrug-resistance phenotypes because of reduced accumulation of cisplatin and other cytotoxic compounds such as methotrexate and heavy metals. The uptake of horseradish peroxidase (HRPO) and Texas Red dextran was decreased several-fold in KB-CP-r cells, indicating a general defect in fluid-phase ... More
Measurement of endosome pH following folate receptor-mediated endocytosis.
AuthorsLee RJ, Wang S, Low PS
JournalBiochim Biophys Acta
PubMed ID8703993
'Free folic acid is believed to enter some cells by folate receptor-mediated endocytosis at membrane invaginations termed caveolae. Folate conjugated macromolecules also enter cells by folate receptor-mediated endocytosis, but their site of entry has never been conclusively identified. In this paper, we show that internalization of folate-macromolecule conjugates by receptor-bearing ... More
Intersection of group I CD1 molecules and mycobacteria in different intracellular compartments of dendritic cells.
AuthorsSchaible UE, Hagens K, Fischer K, Collins HL, Kaufmann SH
JournalJ Immunol
PubMed ID10779793
'Human CD1a, CD1b, and CD1c molecules can present mycobacterial glycolipids to T cells. Because phagosomes containing viable mycobacteria represent early endosomal compartments, we studied where mycobacterial glycolipids intersect with CD1 molecules in infected APC. CD1b and CD1c, but not CD1a, localized to late endosomes/lysosomes. CD1a and CD1c were predominantly expressed ... More
Different fates of phagocytosed particles after delivery into macrophage lysosomes.
AuthorsOh YK, Swanson JA
JournalJ Cell Biol
PubMed ID8647890
'Phagocytosis in macrophages is often studied using inert polymer microspheres. An implicit assumption in these studies is that such particles contain little or no specific information in their structure that affects their intracellular fate. We tested that assumption by examining macrophage phagosomes containing different kinds of particles and found that ... More
Quantitative imaging of cis-regulatory reporters in living embryos.
AuthorsDmochowski IJ, Dmochowski JE, Oliveri P, Davidson EH, Fraser SE
JournalProc Natl Acad Sci U S A
PubMed ID12237411
'A confocal laser scanning microscopy method has been developed for the quantitation of green fluorescent protein (GFP) as a reporter of gene activity in living three-dimensional structures such as sea urchin and starfish embryos. This method is between 2 and 50 times more accurate than conventional confocal microscopy procedures depending ... More
Delivery of macromolecules into live cells by simple co-incubation with a peptide.
AuthorsLee YJ, Erazo-Oliveras A, Pellois JP,
JournalChembiochem
PubMed ID20029930
'n this report, we test the hypothesis that optimized cell-penetrating peptides (CPPs) might deliver macromolecules to the cytosol of live cells by simple co-incubation and without the requirement for any type of conjugation, whether covalent or noncovalent. This hypothesis is based on the observation that the binding of TAT and ... More
Hepatitis C virus glycoprotein complex localization in the endoplasmic reticulum involves a determinant for retention and not retrieval.
AuthorsDuvet S, Cocquerel L, Pillez A, Cacan R, Verbert A, Moradpour D, Wychowski C, Dubuisson J
JournalJ Biol Chem
PubMed ID9822684
'The hepatitis C virus (HCV) genome encodes two envelope glycoproteins (E1 and E2). These glycoproteins interact to form a noncovalent heterodimeric complex which in the cell accumulates in endoplasmic reticulum (ER)-like structures. The transmembrane domain of E2, at least, is involved in HCV glycoprotein complex localization in this compartment. In ... More
Saposin C is required for lipid presentation by human CD1b.
AuthorsWinau F, Schwierzeck V, Hurwitz R, Remmel N, Sieling PA, Modlin RL, Porcelli SA, Brinkmann V, Sugita M, Sandhoff K, Kaufmann SH, Schaible UE
JournalNat Immunol
PubMed ID14716313
'Lipids from Mycobacterium tuberculosis are presented through CD1 proteins to T lymphocytes in humans, but the accessory molecules required for antigen loading and presentation remain unidentified. Here we show that fibroblasts deficient in sphingolipid activator proteins (SAPs) transfected with CD1b failed to activate lipid-specific T cells. However, the T cell ... More
Prion protein protects human neurons against Bax-mediated apoptosis.
AuthorsBounhar Y, Zhang Y, Goodyer CG, LeBlanc A
JournalJ Biol Chem
PubMed ID11522774
'The function of the cellular prion protein (PrP) is still poorly understood. We present here an unprecedented role for PrP against Bax-mediated neuronal apoptosis and show that PrP potently inhibits Bax-induced cell death in human primary neurons. Deletion of four octapeptide repeats of PrP (PrPDeltaOR) and familial D178N and T183A ... More
Calpain activity promotes the sealing of severed giant axons.
'A barrier (seal) must form at the cut ends of a severed axon if a neuron is to survive and eventually regenerate. Following severance of crayfish medial giant axons in physiological saline, vesicles accumulate at the cut end and form a barrier (seal) to ion and dye diffusion. In contrast, ... More
Image analysis of calcium release dynamics.
AuthorsFreisinger CM, Houston DW, Slusarski DC,
JournalMethods Mol Biol
PubMed ID19099252
Many aspects of animal development are dependent on the dynamic release of calcium (Ca2+) ions. Although Ca2+ release within a cell is tightly controlled, how the release dynamics result in a specific biological output in embryonic development is less clear. The integration of pharmacological and molecular-genetic studies with in vivo ... More
Analysis of the lysosomal storage disease Chediak-Higashi syndrome.
Chediak-Higashi syndrome (CHS) is a rare autosomal recessive disorder of human, mouse (beige) and other mammalian species. The same genetic defect was found to result in the disease in all species identified, permitting a positional cloning approach using the mouse model beige to identify the responsible gene. The CHS gene ... More
Fusion pore dynamics and insulin granule exocytosis in the pancreatic islet.
AuthorsTakahashi N, Kishimoto T, Nemoto T, Kadowaki T, Kasai H
JournalScience
PubMed ID12193788
Insulin secretion from intact mouse pancreatic islets was investigated with two-photon excitation imaging. Insulin granule exocytosis occurred mainly toward the interstitial space, away from blood vessels. The fusion pore was unusually stable with a lifetime of 1.8 seconds. Opening of the 1.4-nanometer-diameter pore was preceded by unrestricted lateral diffusion of ... More
Membrane proximal lysosomes are the major vesicles responsible for calcium-dependent exocytosis in nonsecretory cells.
AuthorsJaiswal JK, Andrews NW, Simon SM
JournalJ Cell Biol
PubMed ID12438417
Similar to its role in secretory cells, calcium triggers exocytosis in nonsecretory cells. This calcium-dependent exocytosis is essential for repair of membrane ruptures. Using total internal reflection fluorescence microscopy, we observed that many organelles implicated in this process, including ER, post-Golgi vesicles, late endosomes, early endosomes, and lysosomes, were within ... More
NAADP mobilizes Ca(2+) from reserve granules, lysosome-related organelles, in sea urchin eggs.
AuthorsChurchill GC, Okada Y, Thomas JM, Genazzani AA, Patel S, Galione A
JournalCell
PubMed ID12464181
Nicotinic acid adenine dinucleotide phosphate (NAADP) mobilizes Ca(2+) in many cells and species. Unlike other Ca(2+)-mobilizing messengers, NAADP mobilizes Ca(2+) from an unknown store that is not the endoplasmic reticulum, the store traditionally associated with messenger-mediated Ca(2+) signaling. Here, we demonstrate the presence of a Ca(2+) store in sea urchin ... More
Polymersomes: tough vesicles made from diblock copolymers.
AuthorsDischer BM, Won YY, Ege DS, Lee JC, Bates FS, Discher DE, Hammer DA
JournalScience
PubMed ID10325219
Vesicles were made from amphiphilic diblock copolymers and characterized by micromanipulation. The average molecular weight of the specific polymer studied, polyethyleneoxide-polyethylethylene (EO40-EE37), is several times greater than that of typical phospholipids in natural membranes. Both the membrane bending and area expansion moduli of electroformed polymersomes (polymer-based liposomes) fell within the ... More
Activation of lysosomal function during dendritic cell maturation.
AuthorsTrombetta ES, Ebersold M, Garrett W, Pypaert M, Mellman I
JournalScience
PubMed ID12610307
In response to a variety of stimuli, dendritic cells (DCs) transform from immature cells specialized for antigen capture into mature cells specialized for T cell stimulation. During maturation, the DCs acquire an enhanced capacity to form and accumulate peptide-MHC (major histocompatibility complex) class II complexes. Here we show that a ... More
Monitoring presynaptic calcium dynamics in projection fibers by in vivo loading of a novel calcium indicator.
AuthorsKreitzer AC, Gee KR, Archer EA, Regehr WG
JournalNeuron
PubMed ID10939328
Fluorometric calcium measurements have revealed presynaptic residual calcium (Ca(res)) to be an important regulator of synaptic strength. However, in the mammalian brain, it has not been possible to monitor Ca(res) in fibers that project from one brain region to another. Here, we label neuronal projections by injecting dextran-conjugated calcium indicators ... More
Rac and Cdc42 induce actin polymerization and G1 cell cycle progression independently of p65PAK and the JNK/SAPK MAP kinase cascade.
AuthorsLamarche N, Tapon N, Stowers L, Burbelo PD, Aspenström P, Bridges T, Chant J, Hall A
JournalCell
PubMed ID8898204
Rac and Cdc42 regulate a variety of responses in mammalian cells including formation of lamellipodia and filopodia, activation of the JNK MAP kinase cascade, and induction of G1 cell cycle progression. Rac is also one of the downstream targets required for Ras-induced malignant transformation. Rac and Cdc42 containing a Y40C ... More
Automated identification of neurons in 3D confocal datasets from zebrafish brainstem.
AuthorsKamali M, Day LJ, Brooks DH, Zhou X, O'Malley DM,
JournalJ Microsc
PubMed ID19196418
Many kinds of neuroscience data are being acquired regarding the dynamic behaviour and phenotypic diversity of nerve cells. But as the size, complexity and numbers of 3D neuroanatomical datasets grow ever larger, the need for automated detection and analysis of individual neurons takes on greater importance. We describe here a ... More
Biolistic delivery of Ca2+ dyes into plant and algal cells.
In eukaryotes, changes in cytosolic Ca2+ concentrations ([Ca2+]cyt) are associated with a number of environmental and developmental stimuli. However, measuring [Ca2+]cyt changes in single plant or algal cells is often problematic. Although a wide range of Ca2+-sensitive fluorescent dyes is available, they are often difficult to introduce into plant cells. ... More
Cellular uptake of cyclotide MCoTI-I follows multiple endocytic pathways.
Cyclotides are plant-derived proteins that naturally exhibit various biological activities and whose unique cyclic structure makes them remarkably stable and resistant to denaturation or degradation. These attributes, among others, make them ideally suited for use as drug development tools. This study investigated the cellular uptake of cyclotide, MCoTI-I in live ... More
Retrograde inhibition of presynaptic calcium influx by endogenous cannabinoids at excitatory synapses onto Purkinje cells.
AuthorsKreitzer AC, Regehr WG
JournalNeuron
PubMed ID11301030
Brief depolarization of cerebellar Purkinje cells was found to inhibit parallel fiber and climbing fiber EPSCs for tens of seconds. This depolarization-induced suppression of excitation (DSE) is accompanied by altered paired-pulse plasticity, suggesting a presynaptic locus. Fluorometric imaging revealed that postsynaptic depolarization also reduces presynaptic calcium influx. The inhibition of ... More
Recycling of the insulin-sensitive glucose transporter GLUT4. Access of surface internalized GLUT4 molecules to the perinuclear storage compartment is mediated by the Phe5-Gln6-Gln7-Ile8 motif.
AuthorsPalacios S, Lalioti V, Martinez-Arca S, Chattopadhyay S, Sandoval IV
JournalJ Biol Chem
PubMed ID11031262
The insulin-sensitive glucose transporter GLUT4 is translocated to the plasma membrane in response to insulin and recycled back to the intracellular store(s) after removal of the hormone. We have used clonal 3T3-L1 fibroblasts and adipocyte-like cells stably expressing wild-type GLUT4 to characterize (a) the intracellular compartment where the bulk of ... More
Membrane perforations inhibit lysosome fusion by altering pH and calcium in Listeria monocytogenes vacuoles.
AuthorsShaughnessy LM, Hoppe AD, Christensen KA, Swanson JA
JournalCell Microbiol
PubMed ID16611227
Listeria monocytogenes (Lm) evade microbicidal defences inside macrophages by secreting a pore-forming cytolysin listeriolysin O (LLO), which allows Lm to escape vacuoles. LLO also inhibits Lm vacuole fusion with lysosomes, which indicates LLO alters vacuole chemistry prior to release of Lm into cytoplasm. Using fluorescent probes to measure membrane permeability, ... More
Pleiotropic effects of Pasteurella multocida toxin are mediated by Gq-dependent and -independent mechanisms. involvement of Gq but not G11.
AuthorsZywietz A, Gohla A, Schmelz M, Schultz G, Offermanns S
JournalJ Biol Chem
PubMed ID11062245
Pasteurella multocida toxin (PMT) is a highly potent mitogen for a variety of cell types. PMT has been shown to induce various cellular signaling processes, and it has been suggested to function through the heterotrimeric G-proteins G(q)/G(11). To analyze the role of G(q)/G(11) in the action of PMT, we have ... More
Heterocellular gap junctional communication between alveolar epithelial cells.
AuthorsAbraham V, Chou ML, George P, Pooler P, Zaman A, Savani RC, Koval M
JournalAm J Physiol Lung Cell Mol Physiol
PubMed ID11350787
We analyzed the pattern of gap junction protein (connexin) expression in vivo by indirect immunofluorescence. In normal rat lung sections, connexin (Cx)32 was expressed by type II cells, whereas Cx43 was more ubiquitously expressed and Cx46 was expressed by occasional alveolar epithelial cells. In response to bleomycin-induced lung injury, Cx46 ... More
A fluorescent PEBBLE nanosensor for intracellular free zinc.
AuthorsSumner JP, Aylott JW, Monson E, Kopelman R
JournalAnalyst
PubMed ID11827375
The development and characterisation of a fluorescent optical PEBBLE (Probe Encapsulated By Biologically Localised Embedding) nanosensor for the detection of zinc is detailed. A ratiometric sensor has been fabricated that incorporates two fluorescent dyes; one is sensitive to zinc and the other acts as a reference. The sensing components are ... More
Alteration of intracellular Ca2+ transients in COS-7 cells transfected with the cDNA encoding skeletal-muscle ryanodine receptor carrying a mutation associated with malignant hyperthermia.
AuthorsTreves S, Larini F, Menegazzi P, Steinberg TH, Koval M, Vilsen B, Andersen JP, Zorzato F
JournalBiochem J
PubMed ID8053891
Malignant hyperthermia (MH), an inherited neuromuscular disease triggered by halogenated inhalational anaesthetics and skeletal-muscle relaxants, appears to be due to an alteration of intracellular Ca2+ homoeostasis. MH occurs in 1 out of 20,000 anaesthetized adults and is characterized by hypermetabolism, skeletal-muscle rigidity and elevation in body temperature, which is frequently ... More
The parasitophorous vacuole membrane surrounding intracellular Toxoplasma gondii functions as a molecular sieve.
AuthorsSchwab JC, Beckers CJ, Joiner KA
JournalProc Natl Acad Sci U S A
PubMed ID8290555
The obligate intracellular protozoan parasite Toxoplasma gondii creates and enters into a unique membrane-bounded cytoplasmic compartment, the parasitophorous vacuole, when invading mammalian host cells. By microinjecting polar fluorescent molecules into individual T. gondii-infected fibroblasts, we show here that the parasitophorous vacuole membrane (PVM) surrounding the parasite functions as a molecular ... More
Rabies virus entry into endosomes in IMR-32 human neuroblastoma cells.
AuthorsLewis P, Fu Y, Lentz TL
JournalExp Neurol
PubMed ID9743568
Early events in rabies virus entry into cultured IMR-32 human neuroblastoma cells were investigated. After adsorption of rabies virus to the cell surface in the cold and warming to 37 degrees C in the presence of tracers for early endosomes, rabies virus and tracers were localized by immunofluorescence microscopy. After ... More
Epidermal growth factor-mediated caveolin recruitment to early endosomes and MAPK activation. Role of cholesterol and actin cytoskeleton.
AuthorsPol A, Lu A, Pons M, Peiró S, Enrich C
JournalJ Biol Chem
PubMed ID10889188
The endocytic compartment of eukaryotic cells is a complex intracellular structure involved in sorting, processing, and degradation of a great variety of internalized molecules. Recently, the uptake through caveolae has emerged as an alternative internalization pathway, which seems to be directly related with some signal transduction pathways. However, the mechanisms, ... More
Chemical signaling from colonic smooth muscle cells to DRG neurons in culture.
AuthorsEnnes HS, Young SH, Goliger JA, Mayer EA
JournalAm J Physiol
PubMed ID10069987
Transduction mechanisms between target cells within the intestinal wall and peripheral terminals of extrinsic primary afferent neurons are poorly understood. The purpose of this study was to characterize the interactions between smooth muscle cells from the rat distal colon and lumbar dorsal root ganglion (DRG) neurons in coculture. DRG neurons ... More
ER to Golgi transport: Requirement for p115 at a pre-Golgi VTC stage.
AuthorsAlvarez C, Fujita H, Hubbard A, Sztul E
JournalJ Cell Biol
PubMed ID10601335
The membrane transport factor p115 functions in the secretory pathway of mammalian cells. Using biochemical and morphological approaches, we show that p115 participates in the assembly and maintenance of normal Golgi structure and is required for ER to Golgi traffic at a pre-Golgi stage. Injection of antibodies against p115 into ... More
Injection of sperm extract mimics spatiotemporal dynamics of Ca2+ responses and progression of meiosis at fertilization of ascidian oocytes.
AuthorsKyozuka K, Deguchi R, Mohri T, Miyazaki S
JournalDevelopment
PubMed ID9735370
Sperm extract (SE) of the ascidian, Ciona savignyi, injected into oocytes induced repetitive intracellular Ca2+ increases with kinetics consistent with those at fertilization and caused reinitiation and progression of meiosis as in fertilized oocytes with the formation of polar bodies. The Ca2+ response comprised two sets of Ca2+ oscillations separated ... More
Low-efficiency (macro-)pinocytic internalization of non-pathogenic Escherichia coli into HEp-2 cells.
AuthorsSinai AP, Hayes SF, Small PL, Bavoil PM
JournalRes Microbiol
PubMed ID8584786
HEp-2 cells internalize non-pathogenic Escherichia coli bacteria by a low-efficiency internalization mechanism which is upregulated in Pho-derepressed strains (as shown by Sinai and Bavoil in 1993), and is independent of microfilament integrity but requires functional microtubules. Here, we further characterize the microtubule requirement of this pathway using various effectors of ... More
Light-harvesting ionic dendrimer porphyrins as new photosensitizers for photodynamic therapy.
AuthorsNishiyama N, Stapert HR, Zhang GD, Takasu D, Jiang DL, Nagano T, Aida T, Kataoka K
JournalBioconjug Chem
PubMed ID12526693
Photodynamic therapy (PDT) is a promising therapeutic modality for treatment of solid tumors. In this study, third-generation aryl ether dendrimer porphyrins (DPs) with either 32 quaternary ammonium groups (32(+)DPZn) or 32 carboxylic groups (32(-)DPZn) were evaluated as a novel, supramolecular class of photosensitizers for PDT. DPs showed a different cell-association ... More
Chinese hamster ovary cell lysosomes rapidly exchange contents.
AuthorsFerris AL, Brown JC, Park RD, Storrie B
JournalJ Cell Biol
PubMed ID2447096
We have used cell fusion to address the question of whether macromolecules are rapidly exchanged between lysosomes. Donor cell lysosomes were labeled by the long-term internalization of the fluid-phase pinocytic markers, invertase (sucrase), Lucifer Yellow, FITC-conjugated dextran, or Texas red-conjugated dextran. Recipient cells contained lysosomes swollen by long-term internalization of ... More
Molecular size-fractionation during endocytosis in macrophages.
AuthorsBerthiaume EP, Medina C, Swanson JA
JournalJ Cell Biol
PubMed ID7538141
The sorting of macromolecules within and between membranous organelles is often directed by information contained in protein primary or secondary structure. We show here that absent such structural information, macromolecules internalized by endocytosis in macrophages can be sorted by size. After endocytosis, small solute probes of fluid-phase pinocytosis were recycled ... More
"Synchronized" endocytosis and intracellular sorting in alveolar macrophages: the early sorting endosome is a transient organelle.
AuthorsWard DM, Perou CM, Lloyd M, Kaplan J
JournalJ Cell Biol
PubMed ID7775570
Incubation of alveolar macrophages in hypoosmotic K(+)-containing buffers results in persistent cell swelling and an inability to undergo regulatory volume decrease. We demonstrate that cells incubated in hypo-K+ show an inhibition of endocytosis without any observed alteration in recycling. The inhibition of endocytosis affected all forms of membrane internalization, receptor ... More
Constitutively active Galpha12, Galpha13, and Galphaq induce Rho-dependent neurite retraction through different signaling pathways.
AuthorsKatoh H, Aoki J, Yamaguchi Y, Kitano Y, Ichikawa A, Negishi M
JournalJ Biol Chem
PubMed ID9786865
In neuronal cells, activation of a certain heterotrimeric G protein-coupled receptor causes neurite retraction and cell rounding via the small GTPase Rho. However, the specific heterotrimeric G proteins that mediate Rho-dependent neurite retraction and cell rounding have not yet been identified. Here we investigated the effects of expression of constitutively ... More
Distribution of BDNF and trkB mRNA in the otic region of 3.5 and 4.5 day chick embryos as revealed with a combination of in situ hybridization and tract tracing.
AuthorsHallböök F, Fritzsch B
JournalInt J Dev Biol
PubMed ID9415492
We have used a recently developed technique which combines fluorescent tract tracing and in situ hybridization to study co-localization of neurotrophin mRNA and neurotrophin receptor mRNA expression simultaneously with the pattern of innervation in the developing chick ear. Efferent and afferent fibersfrom the VII/VIIIth cranial nerves were retrogradely and anterogradely ... More
Biochemical and functional characterization of intercellular adhesion and gap junctions in fibroblasts.
AuthorsKo K, Arora P, Lee W, McCulloch C
JournalAm J Physiol Cell Physiol
PubMed ID10898726
Despite their significance in wound healing, little is known about the molecular determinants of cell-to-cell adhesion and gap junctional communication in fibroblasts. We characterized intercellular adherens junctions and gap junctions in human gingival fibroblasts (HGFs) using a novel model. Calcein-labeled donor cells in suspension were added onto an established, Texas ... More
Legionella pneumophila replication vacuoles mature into acidic, endocytic organelles.
AuthorsSturgill-Koszycki S, Swanson MS
JournalJ Exp Med
PubMed ID11067875
After ingestion by macrophages, Legionella pneumophila inhibits acidification and maturation of its phagosome. After a 6-10-h lag period, the bacteria replicate for 10-14 h until macrophage lysis releases dozens of progeny. To examine whether the growth phase of intracellular L. pneumophila determines the fate of its phagosome, interactions between the ... More
Crayfish medial giant axons (MGAs) transected in physiological saline form vesicles which interact with each other, pre-existing vesicles, and/or with the plasmalemma to form an electrical and a physical barrier that seals a cut axonal end within 60 min. The formation of this barrier (seal) was assessed by measuring the ... More
Rac activation upon cell-cell contact formation is dependent on signaling from the epidermal growth factor receptor.
AuthorsBetson M, Lozano E, Zhang J, Braga VM
JournalJ Biol Chem
PubMed ID12147707
Cadherins are transmembrane receptors that mediate cell-cell adhesion. They play an essential role in embryonic development and maintenance of tissue architecture. The Rho family small GTPases regulate actin cytoskeletal dynamics in different cell types. The function of two family members, Rho and Rac, is required for the stability of cadherins ... More
Rac1-induced endocytosis is associated with intracellular proteolysis during migration through a three-dimensional matrix.
AuthorsAhram M, Sameni M, Qiu RG, Linebaugh B, Kirn D, Sloane BF
JournalExp Cell Res
PubMed ID11035924
Transfection of Rat1 fibroblasts with an activated form of rac1 (V12rac1) stimulated cell migration in vitro compared to transfection of Rat1 fibroblasts with vector only or with dominant negative rac1 (N17rac1). To investigate the involvement of proteases in this migration, we used a novel confocal assay to evaluate the ability ... More
Organization of the projections from the pericruciate cortex to the pontomedullary reticular formation of the cat: a quantitative retrograde tracing study.
AuthorsRho MJ, Cabana T, Drew T
JournalJ Comp Neurol
PubMed ID9368839
Dextran-amines were used as retrograde tracers to investigate the organization of cortical projections to different cytoarchitectonic regions of the pontomedullary reticular formation of the cat. Injections into the nucleus reticularis pontis oralis resulted in labelling of neurones in the proreus cortex and area 6a beta of the premotor cortex, with ... More
Gating of epidermal plasmodesmata is restricted to the leading edge of expanding infection sites of tobacco mosaic virus (TMV).
AuthorsOparka KJ, Prior DA, Santa Cruz S, Padgett HS, Beachy RN
JournalPlant J
PubMed ID9375392
Plasmodesmatal gating in epidermal cells of Nicotiana tabacum was examined in expanding infection sites of tobacco mosaic virus (TMV) expressing a fusion between the viral movement protein and the green fluorescent protein (MP-GFP). The infection sites were circular in profile and within 3 days post-inoculation had developed a brightly fluorescent ... More
Expression of 5-HT3 receptors by extrinsic duodenal afferents contribute to intestinal inhibition of gastric emptying.
AuthorsRaybould HE, Glatzle J, Robin C, Meyer JH, Phan T, Wong H, Sternini C
JournalAm J Physiol Gastrointest Liver Physiol
PubMed ID12409280
Intestinal perfusion with carbohydrates inhibits gastric emptying via vagal and spinal capsaicin-sensitive afferent pathways. The aim of the present study was to determine the role of 1) 5-hydroxytryptamine (5-HT)(3) receptors (5-HT(3)R) in mediating glucose-induced inhibition of gastric emptying and 2) 5-HT(3)R expression in vagal and spinal afferents in innervating the ... More
Hypertonic saline therapy in cystic fibrosis: Evidence against the proposed mechanism involving aquaporins.
AuthorsLevin MH, Sullivan S, Nielson D, Yang B, Finkbeiner WE, Verkman AS
JournalJ Biol Chem
PubMed ID16829520
Recent data indicate the clinical benefit of nebulized hypertonic saline in cystic fibrosis lung disease, with a proposed mechanism involving sustained increase in airway surface liquid volume. To account for the paradoxical observation that amiloride suppresses the beneficial effect of hypertonic saline, it has been previously concluded (Donaldson, S. H., ... More
Analysis of post-lysosomal compartments.
AuthorsHirota Y, Masuyama N, Kuronita T, Fujita H, Himeno M, Tanaka Y
JournalBiochem Biophys Res Commun
PubMed ID14733906
Lysosomes are acidic intracellular compartments and are regarded as degradative and the end point, of the endocytic pathway. Here we provide evidence for the generation of acid hydrolase poor and non-acidic post-lysosomal compartments in NRK cells that have accumulated non-digestible macromolecules, Texas red-dextran (TR-Dex), within lysosomes. When TR-Dex was fed ... More
Regulation of cadherin function by Rho and Rac: modulation by junction maturation and cellular context.
AuthorsBraga VM, Del Maschio A, Machesky L, Dejana E
JournalMol Biol Cell
PubMed ID9880323
Cadherins are cell-cell adhesion receptors whose adhesive function requires their association with the actin cytoskeleton via proteins called catenins. The small guanosine triphosphatases (GTPases), Rho and Rac, are intracellular proteins that regulate the formation of distinct actin structures in different cell types. In keratinocytes and in other epithelial cells, Rho ... More
Cellular dimensions affecting the nucleocytoplasmic volume ratio.
AuthorsSwanson JA, Lee M, Knapp PE
JournalJ Cell Biol
PubMed ID1955464
Although it has long been appreciated that larger eukaryotic cells have larger nuclei, little is known about how this size relationship is maintained. Here we describe a method for measuring the aqueous volume ratio of nucleus to cytoplasm, two compartments which are interconnected via the pores in the nuclear envelope. ... More
M-CSF-induced macropinocytosis increases solute endocytosis but not receptor-mediated endocytosis in mouse macrophages.
AuthorsRacoosin EL, Swanson JA
JournalJ Cell Sci
PubMed ID1429898
Although coated vesicles can mediate both solute and receptor-mediated endocytosis, there are other kinds of endocytic vesicles that contribute to these processes. The relative contributions of these other organelles, particularly regarding solute influx, remains unsettled. Here we describe a physiological uncoupling of solute and receptor-mediated endocytosis that occurs during growth ... More
Cell-cell adhesion in human fibroblasts requires calcium signaling.
AuthorsKo KS, Arora PD, Bhide V, Chen A, McCulloch CA
JournalJ Cell Sci
PubMed ID11228159
In connective tissues, intercellular adhesion is essential for tissue morphogenesis, development and wound healing. However, the signaling mechanisms initiated by cell-cell adhesion in fibroblasts and that regulate it are not known. In this study we tested the hypothesis that intracellular calcium signaling is required to mediate intercellular adhesion between fibroblasts. ... More
P-glycoprotein does not reduce substrate concentration from the extracellular leaflet of the plasma membrane in living cells.
AuthorsChen Y, Pant AC, Simon SM
JournalCancer Res
PubMed ID11691790
P-glycoprotein (Pgp), a member of the ATP-binding cassette family of transporters, is an important mediator of multidrug resistance in cancer. Pgp exhibits a very broad specificity for substrates. These substrates share a common feature of being amphipathic and can orient into either leaflet of the membrane bilayer. Current evidence suggests ... More
Three-dimensional localization of wild-type and myosin II mutant cells during morphogenesis of Dictyostelium.
AuthorsKnecht DA, Shelden E
JournalDev Biol
PubMed ID7649374
Dictyostelium amoebae that lack myosin II (mhcA-) are unable to undergo morphogenesis. The cells aggregate slowly to form hemispherical mounds, but the mounds never extend a tip upward. Expression of developmentally regulated genes appears normal in the absence of morphogenesis. When mixed with an excess of wild-type cells, some mutant ... More
Visible evidence for differences in synaptic effectiveness with activity-dependent vesicular uptake and release of FM1-43.
AuthorsQuigley PA, Msghina M, Govind CK, Atwood HL
JournalJ Neurophysiol
PubMed ID9914295
Activity-dependent uptake and release of the fluorescent probe FM1-43 were used to compare synaptic performance (rates of transmitter release and synaptic vesicle turnover) at different frequencies in phasic and tonic motor neurons innervating the crayfish leg extensor muscle and in the tonic motor neuron of the opener muscle. The phasic ... More
Local commissural interneurons integrate information from intersegmental coordinating interneurons.
AuthorsMulloney B, Hall WM
JournalJ Comp Neurol
PubMed ID14556294
The information that coordinates movements of swimmerets on different segments of the crayfish abdomen is conducted by interneurons that originate in each abdominal ganglion. These interneurons project axons to neighboring ganglia and beyond. To discover the anatomy of these axons in their target ganglia, we used Neurobiotin and dextran-Texas Red ... More
PIKfyve Kinase and SKD1 AAA ATPase define distinct endocytic compartments. Only PIKfyve expression inhibits the cell-vacoulating activity of Helicobacter pylori VacA toxin.
AuthorsIkonomov OC, Sbrissa D, Yoshimori T, Cover TL, Shisheva A
JournalJ Biol Chem
PubMed ID12213828
The mammalian phosphatidylinositol (PtdIns)- 5-P/PtdIns-3,5-P(2)-producing kinase PIKfyve and AAA ATPase SKD1, as their yeast counterparts, are implicated in the formation and function of multivesicular bodies/late endosomes. Point mutations inhibiting the enzyme activities convert PIKfyve and SKD1 into dominant-negative mutants (PIKfyve(K1831E) and SKD1(E235Q)), whose expression in cells of kidney origin induces ... More
Dissection of nodulation signaling using pea mutants defective for calcium spiking induced by nod factors and chitin oligomers.
AuthorsWalker SA, Viprey V, Downie JA
JournalProc Natl Acad Sci U S A
PubMed ID11078515
Changes in intracellular calcium in pea root hairs responding to Rhizobium leguminosarum bv. viciae nodulation (Nod) factors were analyzed by using a microinjected calcium-sensitive fluorescent dye (dextran-linked Oregon Green). Within 1-2 min after Nod-factor addition, there was usually an increase in fluorescence, followed about 10 min later by spikes in ... More
Hindered diffusion of high molecular weight compounds in brain extracellular microenvironment measured with integrative optical imaging.
AuthorsNicholson C, Tao L
JournalBiophys J
PubMed ID7508761
This paper describes the theory of an integrative optical imaging system and its application to the analysis of the diffusion of 3-, 10-, 40-, and 70-kDa fluorescent dextran molecules in agarose gel and brain extracellular microenvironment. The method uses a precisely defined source of fluorescent molecules pressure ejected from a ... More
Trafficking of cell surface beta-amyloid precursor protein: retrograde and transcytotic transport in cultured neurons.
AuthorsYamazaki T, Selkoe DJ, Koo EH
JournalJ Cell Biol
PubMed ID7721945
Amyloid beta-protein (A beta), the principal constituent of senile plaques seen in Alzheimer's disease (AD), is derived by proteolysis from the beta-amyloid precursor protein (beta PP). The mechanism of A beta production in neurons, which are hypothesized to be a rich source of A beta in brain, remains to be ... More
Comparative morphology of three types of projection-identified pyramidal neurons in the superficial layers of cat visual cortex.
AuthorsMatsubara JA, Chase R, Thejomayen M
JournalJ Comp Neurol
PubMed ID8866848
The morphology and dendritic organization of corticocortical neurons in the superficial layers of area 18 that project to area 17 were studied by intracellular injection of lucifer yellow in the fixed-slice preparation. This corticocortical population contains primarily standard pyramidal cells, but occasional nonpyramidal, modified, fusiform, star, and inverted pyramidal cells ... More
Multiwavelength optical intrinsic signal imaging of cortical spreading depression.
AuthorsBa AM, Guiou M, Pouratian N, Muthialu A, Rex DE, Cannestra AF, Chen JW, Toga AW
JournalJ Neurophysiol
PubMed ID12424307
Cortical spreading depression (CSD) is an important disease model for migraine and cerebral ischemia. In this study, we exploit the high temporal and spatial resolution of optical imaging to characterize perfusion-dependent and -independent changes in response to CSD and to investigate the etiology of reflectance changes during CSD. In this ... More
Functional gap junctions in corneal fibroblasts and myofibroblasts.
AuthorsSpanakis SG, Petridou S, Masur SK
JournalInvest Ophthalmol Vis Sci
PubMed ID9660479
PURPOSE: Within the corneal stroma, keratocytes communicate through gap junctions. These plasma membrane channels, which connect the cytoplasm of adjacent cells, are composed of connexins. In a cell culture model, an investigation was conducted to determine whether connexin-based gap junction intercellular communication is present in fibroblasts and myofibroblasts, both of ... More
Localization and insulin-regulated relocation of phosphoinositide 5-kinase PIKfyve in 3T3-L1 adipocytes.
AuthorsShisheva A, Rusin B, Ikonomov OC, DeMarco C, Sbrissa D
JournalJ Biol Chem
PubMed ID11112776
The mammalian phosphoinositide kinase PIKfyve catalyzes the synthesis of phosphatidylinositol 5-P and phosphatidylinositol 3,5-P(2), thought essential in cellular functions, including membrane trafficking. To discern the intracellular loci of PIKfyve products' formation, we have examined the localization of PIKfyve protein versus enzymatic activity and a possible acutely regulated redistribution in 3T3-L1 ... More
The small GTPases Rho and Rac are required for the establishment of cadherin-dependent cell-cell contacts.
AuthorsBraga VM, Machesky LM, Hall A, Hotchin NA
JournalJ Cell Biol
PubMed ID9182672
Cadherins are calcium-dependent cell-cell adhesion molecules that require the interaction of the cytoplasmic tail with the actin cytoskeleton for adhesive activity. Because of the functional relationship between cadherin receptors and actin filament organization, we investigated whether members of the Rho family of small GTPases are necessary for cadherin adhesion. In ... More
Transport of bacterial lipopolysaccharide to the golgi apparatus.
AuthorsThieblemont N, Wright SD
JournalJ Exp Med
PubMed ID10449523
Addition of lipopolysaccharide (LPS) to cells in the form of LPS-soluble (s)CD14 complexes induces strong cellular responses. During this process, LPS is delivered from sCD14 to the plasma membrane, and the cell-associated LPS is then rapidly transported to an intracellular site. This transport appears to be important for certain cellular ... More
Cytoskeletal protein ABP-280 directs the intracellular trafficking of furin and modulates proprotein processing in the endocytic pathway.
AuthorsLiu G, Thomas L, Warren RA, Enns CA, Cunningham CC, Hartwig JH, Thomas G
JournalJ Cell Biol
PubMed ID9412467
Furin catalyzes the proteolytic maturation of many proproteins within the trans-Golgi network (TGN)/endosomal system. Furin's cytosolic domain (cd) directs both the compartmentalization to and transit between its manifold processing compartments (i.e., TGN/biosynthetic pathway, cell surface, and endosomes). Here we report the identification of the first furin cd sorting protein, ABP-280 ... More
Localization of the PAK1-, WASP-, and IQGAP1-specifying regions of Cdc42.
AuthorsLi R, Debreceni B, Jia B, Gao Y, Tigyi G, Zheng Y
JournalJ Biol Chem
PubMed ID10514434
The Rho family small GTPase Cdc42 transmits divergent intracellular signals through multiple effector proteins to elicit cellular responses such as cytoskeletal reorganization. Potential effectors of Cdc42 implicated in mediating its cytoskeletal effect in mammalian cells include PAK1, WASP, and IQGAP1. To investigate the determinants of Cdc42-effector specificity, we utilized recombinant ... More
Chloride-sensitive MEQ fluorescence in chick embryo motoneurons following manipulations of chloride and during spontaneous network activity.
AuthorsChub N, Mentis GZ, O'donovan MJ
JournalJ Neurophysiol
PubMed ID16192339
Intracellular Cl(-) ([Cl(-)](in)) homeostasis is thought to be an important regulator of spontaneous activity in the spinal cord of the chick embryo. We investigated this idea by visualizing the variations of [Cl(-)](in) in motoneurons retrogradely labeled with the Cl-sensitive dye 6-methoxy-N-ethylquinolinium iodide (MEQ) applied to cut muscle nerves in the ... More
Human NRAMP2/DMT1, which mediates iron transport across endosomal membranes, is localized to late endosomes and lysosomes in HEp-2 cells.
AuthorsTabuchi M, Yoshimori T, Yamaguchi K, Yoshida T, Kishi F
JournalJ Biol Chem
PubMed ID10751401
NRAMP2 (natural resistance-associated macrophage protein 2)/DMT1 (divalent metal transporter 1) is a divalent metal transporter conserved from prokaryotes to higher eukaryotes that exhibits an unusually broad substrate range, including Fe(2+), Zn(2+), Mn(2+), Cu(2+), Cd(2+), Co(2+), Ni(2+), and Pb(2+), and mediates active proton-coupled transport. Recently, it has been shown that the ... More
The Brn-3 family of POU-domain factors: primary structure, binding specificity, and expression in subsets of retinal ganglion cells and somatosensory neurons.
A search for POU domain sequences expressed in the human retina has led to the identification of three closely related genes: Brn-3a, Brn-3b, and Brn-3c. The structure and expression pattern of Brn-3b was reported earlier (Xiang et al., 1993); we report here the structures and expression patterns of Brn-3a and ... More
Signaling complexes and protein-protein interactions involved in the activation of the Ras and phosphatidylinositol 3-kinase pathways by the c-Ret receptor tyrosine kinase.
AuthorsBesset V, Scott RP, Ibáñez CF
JournalJ Biol Chem
PubMed ID10995764
Proximal signaling events and protein-protein interactions initiated after activation of the c-Ret receptor tyrosine kinase by its ligand, glial cell line-derived neurotrophic factor (GDNF), were investigated in cells carrying native and mutated forms of this receptor. Mutation of Tyr-1062 (Y1062F) in the cytoplasmic tail of c-Ret abolished receptor binding and ... More