Structured RhoGEF recruitment drives myosin II organization on large exocytic vesicles

Kumari Kamalesh, Dagan Segal, Ori Avinoam, Eyal D. Schejter, Ben Zion Shilo

Research output: Contribution to journalArticlepeer-review

Abstract

The Rho family of GTPases plays a crucial role in cellular mechanics by regulating actomyosin contractility through the parallel induction of actin and myosin assembly and function. Using exocytosis of large vesicles in the Drosophila larval salivary gland as a model, we followed the spatiotemporal regulation of Rho1, which in turn creates distinct organization patterns of actin and myosin. After vesicle fusion, low levels of activated Rho1 reach the vesicle membrane and drive actin nucleation in an uneven, spread-out pattern. Subsequently, the Rho1 activator RhoGEF2 distributes as an irregular meshwork on the vesicle membrane, activating Rho1 in a corresponding punctate pattern and driving local myosin II recruitment, resulting in vesicle constriction. Vesicle membrane buckling and subsequent crumpling occur at local sites of high myosin II concentrations. These findings indicate that distinct thresholds for activated Rho1 create a biphasic mode of actomyosin assembly, inducing anisotropic membrane crumpling during exocrine secretion.

Original languageEnglish
Article numberjcs261944
Number of pages12
JournalJournal of Cell Science
Volume137
Issue number13
DOIs
StatePublished - Jul 2024

All Science Journal Classification (ASJC) codes

  • Cell Biology

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