Figure 6.

A model for the function of Ent1 ubiquitylation to initiate a retrograde process. Ent1 binds to the plasma membrane via the interaction of the ENTH domain with PIP₂. The three UBDs of Ent1 bind to ubiquitylated cargo, and the clathrin binding box (CB) recruits clathrin proteins to promote endocytosis. For simplicity, other endocytic components (such as Eps15 that binds NPF modules) are not shown. Ent1 ubiquitylation takes place on early endosomes, probably by Rsp5, a process that dissociates Ent1 from the membrane. An uncharacterized deubiquitylase (DUB) that probably forms a complex with Rsp5 then removes Ub from ubiquitylated Ent1 to enable the cyclic function of Ent1.