Myosin 1b and F-actin are involved in the control of secretory granule biogenesis

Nom de la revue
Scientific Reports
Charlène Delestre-Delacour, Ophélie Carmon, Fanny Laguerre, Catherine Estay-Ahumada, Maïté Courel, Salah Elias, Lydie Jeandel, Margarita Villar Rayo, Juan R. Peinado, Lucie Sengmanivong, Stéphane Gasman, Evelyne Coudrier, Youssef Anouar, Maité Montero-Hadjadje

AbstractHormone secretion relies on secretory granules which store hormones in endocrine cells and release them upon cell stimulation. The molecular events leading to hormone sorting and secretory granule formation at the level of the TGN are still elusive. Our proteomic analysis of purified whole secretory granules or secretory granule membranes uncovered their association with the actomyosin components myosin 1b, actin and the actin nucleation complex Arp2/3. We found that myosin 1b controls the formation of secretory granules and the associated regulated secretion in both neuroendocrine cells and chromogranin A-expressing COS7 cells used as a simplified model of induced secretion. We show that F-actin is also involved in secretory granule biogenesis and that myosin 1b cooperates with Arp2/3 to recruit F-actin to the Golgi region where secretory granules bud. These results provide the first evidence that components of the actomyosin complex promote the biogenesis of secretory granules and thereby regulate hormone sorting and secretion.