title: S100A10-mediated translocation of annexin-A2 to SNARE proteins in adrenergic chromaffin cells undergoing exocytosis.
abstract: In neuroendocrine cells, annexin-A2 is implicated as a promoter of monosialotetrahexosylganglioside (GM1)-containing lipid microdomains that are required for calcium-regulated exocytosis. As soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs) require a specific lipid environment to mediate granule docking and fusion, we investigated whether annexin-A2-induced lipid microdomains might be linked to the SNAREs present at the plasma membrane. Stimulation of adrenergic chromaffin cells induces the translocation of cytosolic annexin-A2 to the plasma membrane, where it colocalizes with SNAP-25 and S100A10. Cross-linking experiments performed in stimulated chromaffin cells indicate that annexin-A2 directly interacts with S100A10 to form a tetramer at the plasma membrane. Here, we demonstrate that S100A10 can interact with vesicle-associated membrane protein 2 (VAMP2) and show that VAMP2 is present at the plasma membrane in resting adrenergic chromaffin cells. Tetanus toxin that cleaves VAMP2 solubilizes S100A10 from the plasma membrane and inhibits the translocation of annexin-A2 to the plasma membrane. Immunogold labelling of plasma membrane sheets combined with spatial point pattern analysis confirmed that S100A10 is present in VAMP2 microdomains at the plasma membrane and that annexin-A2 is observed close to S100A10 and to syntaxin in stimulated chromaffin cells. In addition, these results showed that the formation of phosphatidylinositol (4,5)-bisphosphate (PIP(2)) microdomains colocalized with S100A10 in the vicinity of docked granules, suggesting a functional interplay between annexin-A2-mediated lipid microdomains and SNAREs during exocytosis.
authors.affiliation: Institut des Neurosciences Cellulaires et Intégratives, UPR 3212 CNRS, Université de Strasbourg, 5 rue Blaise Pascal, F-67084 Strasbourg, France.
authors.forename: Emeline
authors.initials: E
authors.lastname: Umbrecht-Jenck
authors.forename: Valérie
authors.initials: V
authors.lastname: Demais
authors.forename: Valérie
authors.initials: V
authors.lastname: Calco
authors.forename: Yannick
authors.initials: Y
authors.lastname: Bailly
authors.forename: Marie-France
authors.initials: MF
authors.lastname: Bader
authors.forename: Sylvette
authors.initials: S
authors.lastname: Chasserot-Golaz
mesh_terms: D018663:Adrenergic Agents / Q000378:metabolism; D017306:Annexin A2 / Q000378:metabolism / Q000502:physiology* / Q000648:ultrastructure; D002462:Cell Membrane / Q000378:metabolism / Q000648:ultrastructure; D019439:Chromaffin Cells / Q000378:metabolism*; D003594:Cytoplasmic Granules / Q000378:metabolism; D005089:Exocytosis / Q000502:physiology*; D006801:Humans; D021381:Protein Transport; D050765:Qa-SNARE Proteins / Q000378:metabolism / Q000648:ultrastructure; D009418:S100 Proteins / Q000378:metabolism / Q000648:ultrastructure; D050600:SNARE Proteins / Q000378:metabolism*; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins / Q000378:metabolism; D050988:Vesicle-Associated Membrane Protein 2 / Q000378:metabolism / Q000648:ultrastructure; D000099248:S100 Calcium Binding Protein A10
chemical_list: D018663:Adrenergic Agents; D017306:Annexin A2; D050765:Qa-SNARE Proteins; D009418:S100 Proteins; D050600:SNARE Proteins; D052067:Soluble N-Ethylmaleimide-Sensitive Factor Attachment Proteins; D050988:Vesicle-Associated Membrane Protein 2; D000099248:S100 Calcium Binding Protein A10