Yeast dynamin implicated in endocytic scission and the disassembly of endocytic components

Abstract

The yeast dynamin-related GTPase Vps1 has been implicated in a range of cellular functions including vacuolar protein sorting, protein trafficking, organization of peroxisome and endocytosis.1,2 Vps1 is present at endocytic sites and may be directly involved in endocytic vesicle invagination through its membrane-tubulating activity. Here, evidence supporting the functional link between Vps1 and the yeast amphiphysin Rvs167 in vesicle invagination is discussed. Though the disassembly of endocytic factors from pinched-off endocytic vesicles appears to be tightly regulated in a spatiotemporal manner, we are far from having complete understanding of the underlying mechanism. In this study, we provide evidence that Vps1 plays a role in the uncoating of endocytic proteins from post-internalized vesicles, based on the observation of a quick disassembly of two endocytic coat proteins Ent1 and Ent2 in cells lacking Vps1.

Keywords: Rvs167; Vps1; disassembly; dynamin; endocytic factors; endocytosis; invagination.

Figure 1

The spatiotemporal regulation of the assembly and disassembly of endocytic factors. (A) Recruitment of endocytic machinery to the cortical endocytic sites. Note that a yeast dynamin-like protein Vps1 and the amphiphysins are recruited after initiation of actin assembly. (B) Uncoating of endocytic factors. The phosphorylation activity of the homologous protein kinases, Prk1 and Ark1, has been implicated in the disassembly of endocytic proteins, including Sla1, Pan1, Ent1 and Ent2. (C) The mean uncoating times for GFP-fused endocytic factors. The time spent by a post-internalized vesicle carrying GFP-fused protein in the cytoplasm was determined.