Regulation of Clathrin-Mediated Endocytosis by Dynamic Ubiquitination/Deubiquitination of Ede1
Clathrin-mediated endocytosis in budding yeast requires the regulated recruitment and disassociation of over 60 proteins at discreet plasma membrane puncta. Post-translational modifications, such as phosphorylation and ubiquitination, may play important regulatory roles in this highly processive and ordered process. However, while ubiquitination plays an important role in cargo selection, functions for ubiquitination of the endocytic machinery are not known. We identified the deubiquitinase (DUB) Ubp7p as a late arriving endocytic protein. Deletion of the DUBs Ubp2p and Ubp7p resulted in elongation of the lifetimes of endocytic coat proteins at the plasma membrane and recruitment of endocytic proteins to internal membranes. These phenotypes could be replicated by expressing a permanently ubiquitinated version of the early endocytic adaptor Ede1p, the yeast Eps15 homolog, which is implicated in the initiation of endocytic sites. However, Ede1p absence did not fully suppress the deubiquitinase deletion phenotype, suggesting that Ede1p is not the only endocytic target whose deubiquitination affects coat formation and disassembly.