Multiple Pathways Regulate Endocytic Coat Disassembly in Saccharomyces cerevisiae for Optimal Downstream Trafficking

Recently, a pathway involving the highly choreographed recruitment of endocytic proteins to sites of clathrin/actin-mediated endocytosis has been revealed in budding yeast. Here, we investigated possible roles for candidate disassembly factors in regulation of the dynamics of the endocytic coat proteins Sla2p, Ent1p, Ent2p, Sla1p, Pan1p and End3p, each of which has mammalian homologues. Live cell imaging analysis revealed that in addition to the synaptojanin, Sjl2p, the Ark1p and Prk1p protein kinases, the putative Arf GTPase-activating protein, Gts1p and the Arf GTPase-interacting protein, Lsb5p, also arrive at endocytic sites late in the internalization pathway, consistent with roles in coat disassembly. Analysis of coat dynamics in various mutant backgrounds revealed that multiple pathways, including the ones mediated by an Arf guanosine triphosphatase and a synaptojanin, facilitate efficient disassembly of different endocytic coat proteins. In total, at least four separate processes are important for disassembly of endocytic complexes and efficient downstream trafficking of endocytic cargo.