ROLE OF DYNAMIN IN THE FORMATION OF TRANSPORT VESICLES FROM THE TRANS-GOLGI NETWORK

Dynamin guanosine triphosphatases support the scission of clathrin-coa ted vesicles from the plasmalemma during endocytosis. By fluorescence microscopy of cultured rat hepatocytes, a green fluorescent protein-dy namin II fusion protein localized with clathrin-coated vesicles at the Golgi complex. A cell-free assay was utilized to demonstrate the role of dynamin in vesicle formation at the trans-Golgi. Addition of pepti de-specific anti-dynamin antibodies to the assay mixture inhibited bot h constitutive exocytic and clathrin-coated vesicle formation. Immunod epletion of dynamin proteins also inhibited vesicle formation, and bud ding efficiency was restored upon readdition of purified dynamin. Thes e data suggest that dynamin participates in the formation of distinct transport vesicles from the trans-Golgi network.