The class V myosin motor, myosin 5c, localizes to mature secretory vesicles and facilitates exocytosis in lacrimal acini
- 1 July 2008
- journal article
- research article
- Published by American Physiological Society in American Journal of Physiology-Cell Physiology
- Vol. 295 (1), C13-C28
- https://doi.org/10.1152/ajpcell.00330.2007
Abstract
We investigated the role of the actin-based myosin motor, myosin 5c (Myo5c) in vesicle transport in exocrine secretion. Lacrimal gland acinar cells (LGAC) are the major source for the regulated secretion of proteins from the lacrimal gland into the tear film. Confocal fluorescence and immunogold electron microscopy revealed that Myo5c was associated with secretory vesicles in primary rabbit LGAC. Upon stimulation of secretion with the muscarinic agonist, carbachol, Myo5c was also detected in association with actin-coated fusion intermediates. Adenovirus-mediated expression of green fluorescent protein (GFP) fused to the tail domain of Myo5c (Ad-GFP-Myo5c-tail) showed that this protein was localized to secretory vesicles. Furthermore, its expression induced a significant ( P ≤ 0.05) decrease in carbachol-stimulated release of two secretory vesicle content markers, secretory component and syncollin-GFP. Adenovirus-mediated expression of GFP appended to the full-length Myo5c (Ad-GFP-Myo5c-full) was used in parallel with adenovirus-mediated expression of GFP-Myo5c-tail in LGAC to compare various parameters of secretory vesicles labeled with either GFP-labeled protein in resting and stimulated LGAC. These studies revealed that the carbachol-stimulated increase in secretory vesicle diameter associated with compound fusion of secretory vesicles that was also exhibited by vesicles labeled with GFP-Myo5c-full was impaired in vesicles labeled with GFP-Myo5c-tail. A significant decrease in GFP labeling of actin-coated fusion intermediates was also seen in carbachol-stimulated LGAC transduced with GFP-Myo5c-tail relative to LGAC transduced with GFP-Myo5c-full. These results suggest that Myo5c participates in apical exocytosis of secretory vesicles.Keywords
This publication has 54 references indexed in Scilit:
- Direct interaction between Rab3D and the polymeric immunoglobulin receptor and trafficking through regulated secretory vesicles in lacrimal gland acinar cellsAmerican Journal of Physiology-Cell Physiology, 2008
- Mast cells possess distinct secretory granule subsets whose exocytosis is regulated by different SNARE isoformsProceedings of the National Academy of Sciences of the United States of America, 2008
- The globular tail domain puts on the brake to stop the ATPase cycle of myosin VaProceedings of the National Academy of Sciences of the United States of America, 2008
- Rab27b regulates number and secretion of platelet dense granulesProceedings of the National Academy of Sciences of the United States of America, 2007
- Effects of α1D-adrenergic receptors on shedding of biologically active EGF in freshly isolated lacrimal gland epithelial cellsAmerican Journal of Physiology-Cell Physiology, 2006
- Involvement of Myosin Vb in Glutamate Receptor TraffickingJournal of Biological Chemistry, 2006
- Actin and non-muscle myosin II facilitate apical exocytosis of tear proteins in rabbit lacrimal acinar epithelial cellsJournal of Cell Science, 2005
- Rab27b localizes to zymogen granules and regulates pancreatic acinar exocytosisBiochemical and Biophysical Research Communications, 2004
- Adenoviral capsid modulates secretory compartment organization and function in acinar epithelial cells from rabbit lacrimal glandGene Therapy, 2004
- Cytoplasmic dynein participates in apically targeted stimulated secretory traffic in primary rabbit lacrimal acinar epithelial cellsJournal of Cell Science, 2003