Defective gating of the Sec61 translocon results in reorganisation of the actin cytoskeleton and perturbed formation of the actomyosin contractile ring

Abstract

The Sec61 complex sits between the distinct environments of the cytosol and the ER lumen and it's appropriate gating is essential to prevent the deleterious flux of molecules and ions between them. Using the sss1-7 mutant we show that actin dynamics is grossly perturbed when translocon gating is defective. Importantly, normal actin morphology is restored when sss1-7 translocon gating defects are suppressed or when these cells are treated with cell-permeable Ca²⁺ chelators. Our findings underscore the importance of translocon gating, particularly in regulating Ca²⁺ homeostasis, in the overall regulation and functional distribution of the actin cytoskeleton.

Keywords: Actin; Sec61 complex; Sss1p; Translocon gating.