UNC-31 (CAPS) Is Required for Dense-Core Vesicle But Not Synaptic Vesicle Exocytosis in Caenorhabditis elegans
| Autor: | Kouichi Iwasaki, Matt Petrie, Kyoungsook Ann, Michael Ailion, Erik M. Jorgensen, Kim Schuske, Sean D. Speese, Thomas Martin |
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| Jazyk: | angličtina |
| Rok vydání: | 2007 |
| Předmět: |
Vesicle fusion
General Neuroscience Secretory Vesicles Calcium-Binding Proteins Molecular Sequence Data SNAP25 Munc-18 Articles Kiss-and-run fusion Biology Secretory Vesicle Exocytosis Cell biology Synaptic vesicle exocytosis Synaptic vesicle recycling Animals Amino Acid Sequence Synaptic Vesicles Caenorhabditis elegans Caenorhabditis elegans Proteins Carrier Proteins |
| Popis: | Previous studies indicated that CAPS (calcium-dependent activator protein for secretion) functions as an essential component for the Ca(2+)-dependent exocytosis of dense-core vesicles in neuroendocrine cells. However, recent mouse knock-out studies suggested an alternative role in the vesicular uptake or storage of catecholamines. To genetically assess the functional role of CAPS, we characterized the sole Caenorhabditis elegans CAPS ortholog UNC-31 (uncoordinated family member) and determined its role in dense-core vesicle-mediated peptide secretion and in synaptic vesicle recycling. Novel assays for dense-core vesicle exocytosis were developed by expressing a prepro-atrial natriuretic factor–green fluorescent protein fusion protein in C. elegans. unc-31 mutants exhibited reduced peptide release in vivo and lacked evoked peptide release in cultured neurons. In contrast, cultured neurons from unc-31 mutants exhibited normal stimulated synaptic vesicle recycling measured by FM4-64 [N-(3-triethylammoniumpropyl)-4-(6-(4-diethylamino)phenyl)hexatrienyl)pyridinium dibromide] dye uptake. Conversely, UNC-13, which exhibits sequence homology to CAPS/UNC-31, was found to be essential for synaptic vesicle but not dense-core vesicle exocytosis. These findings indicate that CAPS/UNC-31 function is not restricted to catecholaminergic vesicles but is generally required for and specific to dense-core vesicle exocytosis. Our results suggest that CAPS/UNC-31 and UNC-13 serve parallel and dedicated roles in dense-core vesicle and synaptic vesicle exocytosis, respectively, in the C. elegans nervous system. |
| Databáze: | OpenAIRE |
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