title: Clathrin light chain directs endocytosis by influencing the binding of the yeast Hip1R homologue, Sla2, to F-actin.
abstract: The role of clathrin light chain (CLC) in clathrin-mediated endocytosis is not completely understood. Previous studies showed that the CLC N-terminus (CLC-NT) binds the Hip1/Hip1R/Sla2 family of membrane/actin-binding factors and that overexpression of the CLC-NT in yeast suppresses endocytic defects of clathrin heavy-chain mutants. To elucidate the mechanistic basis for this suppression, we performed synthetic genetic array analysis with a clathrin CLC-NT deletion mutation (clc1-Δ19-76). clc1-Δ19-76 suppressed the internalization defects of null mutations in three late endocytic factors: amphiphysins (rvs161 and rvs167) and verprolin (vrp1). In actin sedimentation assays, CLC binding to Sla2 inhibited Sla2 interaction with F-actin. Furthermore, clc1-Δ19-76 suppression of the rvs and vrp phenotypes required the Sla2 actin-binding talin-Hip1/R/Sla2 actin-tethering C-terminal homology domain, suggesting that clc1-Δ19-76 promotes internalization by prolonging actin engagement by Sla2. We propose that CLC directs endocytic progression by pruning the Sla2-actin attachments in the clathrin lattice, providing direction for membrane internalization.
authors.affiliation: Department of Molecular and Cellular Pharmacology, University of Miami, Miami, FL 33101, USA.
authors.forename: Douglas R
authors.initials: DR
authors.lastname: Boettner
authors.forename: Helena
authors.initials: H
authors.lastname: Friesen
authors.forename: Brenda
authors.initials: B
authors.lastname: Andrews
authors.forename: Sandra K
authors.initials: SK
authors.lastname: Lemmon
mesh_terms: D008841:Actin Cytoskeleton / Q000235:genetics / Q000378:metabolism; D000199:Actins / Q000235:genetics / Q000378:metabolism; D001692:Biological Transport; D002462:Cell Membrane; D033941:Clathrin Light Chains / Q000235:genetics* / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism*; D004705:Endocytosis / Q000235:genetics; D015966:Gene Expression Regulation, Fungal; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D012441:Saccharomyces cerevisiae / Q000235:genetics* / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics* / Q000378:metabolism*; D017384:Sequence Deletion
chemical_list: D000199:Actins; D033941:Clathrin Light Chains; D003598:Cytoskeletal Proteins; D008840:Microfilament Proteins; C089181:RVS161 protein, S cerevisiae; C082282:RVS167 protein, S cerevisiae; C082266:SLA2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; C090350:VRP1 protein, S cerevisiae