The Yeast Endocytic Protein Epsin-2 Functions in a Cell Division and Septin Organization Pathway

MUKHERJEE D; COON BG.; HANNA CB; LONGHI SA; RETEGUI LA; WENDLAND B; MCCAFFERY JM; BI E; AGUILAR RC

San Diego, CA, USA

Congreso; ASCB 49th Annual Meeting; 2009

ASCB

The epsins are a family of adaptors involved in recruiting other endocytic proteins, binding ofubiquitylated cargo and induction of membrane curvature. These molecules bear a characteristicEpsin N-Terminal Homology (ENTH) domain and multiple peptide motifs that mediate proteinproteininteractions. We have previously demonstrated that the ENTH domain of epsin is involvedin Cdc42 signaling regulation. Here, we present evidence that yeast epsin-2 (Ent2) plays asignaling role during cell division. We observed that overexpression of the ENTH domain of Ent2(ENTH2), but not Ent1, promoted the formation of chains of cells and aberrant septa. Thisdominant-negative effect resulted from ENTH2-mediated interference with septin assemblypathways. We mapped the ENTH2 determinants responsible for induction of the phenotype andfound them to be important for efficient binding to the septin regulatory protein, Bem3. Supportinga physiological role for epsin-2 in cell division, the protein localized to sites of polarized growthand cytokinesis and rescued a cell division defect induced by Bem3 misregulation. Collectively,our findings provide a potential molecular mechanism linking endocytosis (via epsin-2) withsignaling pathways regulating cell division.