The role of myosin 1c and myosin 1b in surfactant exocytosis

Kittelberger, N; Breunig, M; Martin, R; Knölker, H; Miklavc, P

Abstract

Actin and actin-associated proteins have a pivotal effect on regulated exocytosis in secretory cells and influence pre-fusion as well as post-fusion stages of exocytosis. Actin polymerization on secretory granules during the post-fusion phase (formation of an actin coat) is especially important in cells with large secretory vesicles or poorly soluble secretions. Alveolar type II (ATII) cells secrete hydrophobic lipo-protein surfactant, which does not easily diffuse from fused vesicles. Previous work showed that compression of actin coat is necessary for surfactant extrusion. Here, we investigate the role of class 1 myosins as possible linkers between actin and membranes during exocytosis. Live-cell microscopy showed translocation of fluorescently labeled myosin 1b and myosin 1c to the secretory vesicle membrane after fusion. Myosin 1c translocation was dependent on its pleckstrin homology domain. Expression of myosin 1b and myosin 1c constructs influenced vesicle compression rate, whereas only the inhibition of myosin 1c reduced exocytosis. These findings suggest that class 1 myosins participate in several stages of ATII cell exocytosis and link actin coats to the secretory vesicle membrane to influence vesicle compression.

Citation

Kittelberger, N., Breunig, M., Martin, R., Knölker, H., & Miklavc, P. (2016). The role of myosin 1c and myosin 1b in surfactant exocytosis. Journal of Cell Science, 129(8), 1685-1696. https://doi.org/10.1242/jcs.181313

• Journal Article Type: Article
• Acceptance Date: Feb 25, 2016
• Online Publication Date: Apr 15, 2016
• Publication Date: Apr 15, 2016
• Deposit Date: Oct 24, 2016
• Publicly Available Date: Oct 24, 2016
• Journal: Journal of Cell Science
• Print ISSN: 0021-9533
• Electronic ISSN: 1477-9137
• Publisher: Company of Biologists
• Volume: 129
• Issue: 8
• Pages: 1685-1696
• DOI: https://doi.org/10.1242/jcs.181313
• Publisher URL: http://dx.doi.org/10.1242/jcs.181313
• Related Public URLs: http://jcs.biologists.org/
• Additional Information: Funders : Ministerium für Wissenschaft, Forschung und Kunst Baden Wuerttemberg;Deutsche Forschungsgemeinschaft (D-1402/3-1)