Negative Regulation of Yeast Eps15-like Arp2/3 Complex Activator, Pan1p, by the Hip1R-related Protein, Sla2p, during Endocytosis

• DOI: 10.1091/mbc.e06-09-0788
• Publication Date: 2006-12-07T02:25:32Z
• Authors: Jiro Toshima; Junko Y. Toshima; Mara C. Duncan; M. Jamie T.V. Cope; Yidi Sun; Adam C. Martin; Scott Anderson; John R. Yates; Kensaku Mizuno; David G. Drubin
• Keywords: Internalization; Actin remodeling

Control of actin assembly nucleated by the Arp2/3 complex plays a crucial role during budding yeast endocytosis. The Eps15-related activator, Pan1p, is essential for endocytic internalization and proper organization. Pan1p activity negatively regulated Prk1 kinase phosphorylation after internalization. Phosphorylated probably then dephosphorylated in cytosol. recruited to sites approximately 25 s before initiation polymerization, suggesting that its activation kept inactive early stages endocytosis yet-to-be-identified mechanism. However, how maintained an state not clear. Using tandem affinity purification-tagged we identified End3p as stoichiometric component complex, Sla2p, Hip1R-related protein, novel binding partner Pan1p. Interestingly, Sla2p specifically inhibited vitro. coiled-coil region was important inhibition, pan1 partial loss-of-function mutant suppressed temperature sensitivity, phenotypes, phenotypes observed sla2DeltaCC cells lack region. Overall, our results establish Sla2p's regulation controlling Pan1p-stimulated polymerization