Interplay between Rab27a effectors in pancreatic β-cells

Figure 5 Rab27a GTP/GDP cycling synchronizes with the recycling of secretory membrane. In the basal state, GTP-bound Rab27a controls insulin secretion at pre-exocytotic stages via its GTP-specific effectors. Glucose stimulation causes insulin exocytosis. Glucose stimulation also converts Rab27a from its GTP- to its GDP-bound form. GDP-bound Rab27a interacts with IQGAP1, recruits coronin 3, and controls endocytosis of the secretory granule membrane. GAPs: GTPase-activating proteins.