A5068330316- Cellular transport and secretion
- Lipid Membrane Structure and Behavior
- Calcium signaling and nucleotide metabolism
- Erythrocyte Function and Pathophysiology
- Pancreatic function and diabetes
- Protein Kinase Regulation and GTPase Signaling
- Microtubule and mitosis dynamics
- Adrenal and Paraganglionic Tumors
- Cellular Mechanics and Interactions
- Signaling Pathways in Disease
- Neuroscience and Neuropharmacology Research
- Receptor Mechanisms and Signaling
- Pituitary Gland Disorders and Treatments
- Neuropeptides and Animal Physiology
- Retinal Development and Disorders
- Alzheimer's disease research and treatments
- Cancer, Hypoxia, and Metabolism
- Advanced biosensing and bioanalysis techniques
- Cell Adhesion Molecules Research
- Neuroendocrine Tumor Research Advances
- Trace Elements in Health
- Caveolin-1 and cellular processes
- Immunotherapy and Immune Responses
- S100 Proteins and Annexins
- Metabolism, Diabetes, and Cancer
University of Puerto Rico at Carolina
2014-2025
Centre National de la Recherche Scientifique
2012-2024
Institut des Neurosciences Cellulaires et Intégratives
2015-2024
Boston Medical Center
2024
Université de Strasbourg
2014-2023
Centre National pour la Recherche Scientifique et Technique (CNRST)
2021
Inserm
1996-2017
Max Planck Institute of Molecular Cell Biology and Genetics
2003
Institute of Oncology Ljubljana
1999
Université de Rouen Normandie
1996
In neuroendocrine cells, actin reorganization is a prerequisite for regulated exocytosis. Small GTPases, Rho proteins, represent potential candidates coupling dynamics to membrane trafficking events. We previously reported that Cdc42 plays an active role in exocytosis chromaffin cells. The aim of the present work was dissect molecular effector pathway integrating architecture required secretory reaction Using PC12 cells as model, we show activated at plasma during Expression constitutively...
Selenoproteins contain the essential trace element selenium, deficiency of which is associated with cancer or accelerated aging. Although selenoproteins are thought to be instrumental for effects biological function many these proteins remains unknown. Here, we studied role selenoprotein T (SelT), a selenocysteine (Sec) -containing protein no known function, have identified as novel target gene neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) during PC12 cell...
Membrane fusion underlies multiple processes, including exocytosis of hormones and neurotransmitters. starts with the formation a narrow pore. Radial expansion this pore completes process allows fast release secretory compounds, but step remains poorly understood. Here we show that inhibiting expression small GTPase Cdc42 or preventing its activation dominant negative construct in human neuroendocrine cells impaired by compromising enlargement. Consequently mode vesicle was shifted from...
Rho, Rac, and Cdc42 monomeric GTPases are well known regulators of the actin cytoskeleton phosphoinositide metabolism have been implicated in hormone secretion endocrine cells. Here, we examine their possible implication Ca<sup>2+</sup>-dependent exocytosis neurotransmitters. Using subcellular fractionation procedures, found that RhoA, RhoB, Rac1, present rat brain synaptosomes; however, only Rac1 was associated with highly purified synaptic vesicles. To determine function these GTPases,...
The immune synapse (IS) forms as dendritic cells (DCs) and T interact in lymph nodes during initiation of adaptive immunity. Factors that contribute to the formation maintenance IS stability function have been mostly studied cells, whereas little is known about events occurring DCs. Here, we show DCs activated by Toll-like receptor (TLR) agonists reorient microtubule-organizing center (MTOC) toward interacting cell antigen-specific through a mechanism depends on Rho GTPase Cdc42. IL-12,...
Over the past years, dynamin has been implicated in tuning amount and nature of transmitter released during exocytosis. However, mechanism involved remains poorly understood. Here, using bovine adrenal chromaffin cells, we investigated whether this rely on dynamin’s ability to remodel actin cytoskeleton. According idea, inhibition GTPase activity suppressed calcium-dependent de novo cortical altered network. Similarly, expression a small interfering RNA directed against dynamin-2, an isoform...
Glycerophospholipids (GPLs) play important roles in cellular compartmentalization and signaling. Among them, phosphatidic acids (PA) exist as many distinct species depending on acyl chain composition, each one potentially displaying unique signaling function. Although the functions of PA have already been demonstrated multiple processes, specific individual remain obscure due to a lack appropriate tools. Indeed, current synthetic analogues fail preserve all natural PA. To circumvent these...
Besides having a role in signal transduction, heterotrimeric G proteins may be involved membrane trafficking events. In chromaffin cells, Go is associated with secretory organelles, and its activation inhibits the ATP-dependent priming of exocytosis. By using permeabilized we previously described that control exerted by granule-bound on exocytosis related to effects cortical actin network through sequence possibly involving Rho. To provide further insight into function Rho exocytosis, focus...
Chromogranin A (CgA) has been proposed to play a major role in the formation of dense-core secretory granules (DCGs) neuroendocrine cells. Here, we took advantage unique features frog CgA (fCgA) assess this granin and its potential functional determinants hormone sorting during DCG biogenesis. Expression fCgA constitutively secreting COS-7 cells induced mobile vesicular structures, which contained cotransfected peptide hormones. The hormones coexpressed newly formed vesicles could be...
Ras GTPases were long thought to function exclusively from the plasma membrane (PM).However, a current model suggests that proteins can compartmentalize regulate different functions, and an oncogenic H-Ras mutant is restricted endomembrane still transform cells.In this study, we demonstrated cells transformed by endomembrane-restricted formed tumors in nude mice.To define downstream targets of pathways, analyzed Cdc42, which concentrates has been shown act Schizosaccharomyces pombe.Our data...
Calcium-regulated exocytosis in neuroendocrine cells and neurons is accompanied by the redistribution of phosphatidylserine (PS) to extracellular space, leading a disruption plasma membrane asymmetry. How why outward translocation PS occurs during secretion are currently unknown. Immunogold labeling on sheets coupled with hierarchical clustering analysis demonstrate that at vicinity secretory granule fusion sites. We found altering function phospholipid scramblase-1 (PLSCR-1) expressing...
Rho GTPases are crucial regulators of actin cytoskeletal rearrangements and play important roles in many cell functions linked to membrane trafficking processes. In neuroendocrine cells, we have previously demonstrated that RhoA Cdc42 mediate part the remodelling vesicular events required for release hormones by exocytosis. Here, investigate functional importance Rac1 exocytotic reaction dissect downstream upstream molecular might integrate it machinery. Using PC12 found is associated with...
In secretory cells, calcium-regulated exocytosis is rapidly followed by compensatory endocytosis. Neuroendocrine cells secrete hormones and neuropeptides through various modes of exo-endocytosis, including kiss-and-run, cavicapture full-collapse fusion. During kiss-and-run modes, the granule membrane maintained in an omega shape, whereas it completely merges with plasma during mode. As composition very different from that membrane, a precise sorting process granular proteins must occur....
By regulating actin cytoskeleton dynamics, Rho GTPases and their activators RhoGEFs are implicated in various aspects of neuronal differentiation, including dendritogenesis synaptogenesis. Purkinje cells (PCs) the cerebellum, by developing spectacular dendrites covered with spines, represent an attractive model system which to decipher molecular signaling underlying these processes. To identify novel regulators dendritic spine morphogenesis among members poorly characterized DOCK family...
Intersectins (ITSNs) are a family of highly conserved proteins with orthologs from nematodes to mammals. In vertebrates, ITSNs encoded by two genes (itsn1 and itsn2), which act as scaffolds that were initially discovered involved in endocytosis. Further investigation demonstrated ITSN1 is also implicated several other processes including regulated exocytosis, thereby suggesting role for the coupling between exocytosis endocytosis excitatory cells. Despite high degree conservation amongst...