Arp2/3 complex regulates adipogenesis by controlling cortical actin remodeling

Extensive actin cytoskeleton remodeling occurs during adipocyte development. We previously showed that disruption of stress fibers by the actin-severing protein cofilin is a requisite step in adipogenesis. However, it remains unclear whether actin nucleation and assembly into the cortical structure is essential for adipocyte development. Here we investigated the role of cortical actin assembly and of actin nucleation by the Arp2/3 complex in adipogenesis. Cortical actin structure formation started with accumulation of F-actin patches near the plasma membrane during adipogenesis. Depletion of Arp2/3 by knockdown of its subunits Arp3 or ARPC3 strongly impaired adipocyte differentiation, while adipogenesis-initiating factors were unaffected. Moreover, the assembly of F-actin-rich structures at the plasma membrane was suppressed and cortical actin structure poorly developed after adipogenic induction in Arp2/3-deficient cells. Finally, we provide evidence that the cortical actin cytoskeleton is essential for efficient GLUT4 vesicle exocytosis and insulin signal transduction. These results show that the Arp2/3 complex is an essential regulator of adipocyte development by controlling the formation of cortical actin structures, which may facilitate nutrient uptake and signaling events.
Source: BJ Cell - Category: Biochemistry Authors: Tags: BJ Cell Source Type: research