Yeast dynamin Vps1 associates with clathrin to facilitate vesicular trafficking and controls Golgi homeostasis

Abstract

The yeast dynamin Vps1 acts cooperatively with many proteins at diverse cellular locations for endocytosis, protein sorting, and membrane fusion and fission. It has been proposed that Vps1 is functionally linked to clathrin heavy chain 1 (Chc1), but the question of how, where, and when they function together remains unknown. Here we report that Vps1 arrives at the Golgi after clathrin, and that loss of Vps1 leads to a shift in the cellular localization of clathrin to the late endosome and vacuole, not vice versa. Our two-hybrid-based approach provides evidence that full-length Vps1 and its truncated versions bind to the C-terminal region of the Chc1. Cells lacking both Vps1 and Chc1 displayed more severe defects in carboxypeptidase Y (CPY) sorting at the Golgi than those in Vps1-deficient cells. Further, these Vps1 fragments became dominant-negative for CPY sorting upon overexpression. These results suggest that Vps1 binds to Chc1 and functions together at the Golgi for efficient Golgi-to-endosome membrane trafficking. In addition, we found that Vps1, without the aid of clathrin, plays a role in controlling the number and turnover of late Golgi.