The Rsp5 ubiquitin ligase binds to and ubiquitinates members of the yeast CIN85-endophilin complex, Sla1-Rvs167.
Sla1 and Rvs167 are yeast proteins required for receptor internalization and organization of the actin cytoskeleton. Here we provide evidence that Sla1 and Rvs167 are orthologues of the mammalian CIN85 and endophilin proteins, respectively, which are required for ligand-stimulated growth factor receptor internalization. Sla1 is similar in domain structure to CIN85 and binds directly to the endophilin-like Rvs167. Akin to CIN85, Sla1 interacts with synaptojanins and a ubiquitin ligase that regulates endocytosis. This ubiquitin ligase, Rsp5, binds directly to both Sla1 and Rvs167. The interaction between Rsp5 and Rvs167 is mediated through Rsp5 WW domains and PXY motifs in the central Gly-Pro-Ala-rich domain of Rvs167. Rvs167 PXY motifs are required for Rsp5-dependent monoubiquitination of Rvs167 on Lys481 in the Src homology 3 (SH3) domain. Mutation of Lys481 --> Arg causes cells to grow slowly on medium containing 1 M NaCl, although this phenotype is not due to the defect in ubiquitination caused by the K481R mutation. We propose that Rsp5 interaction with Sla1-Rvs167 promotes Rvs167 ubiquitination and regulates activity of this protein complex. Rvs167 ubiquitination is not required for general function of Rvs167, but may control specific Rvs167 SH3 domain-protein interactions or negatively regulate SH3 domain activity.
Stamenova
Svetoslava D
SD
Department of Biochemistry, Molecular Biology and Cell Biology, Northwestern University, Evanston, Illinois 60208-3500, USA.
Dunn
Rebecca
R
Adler
Adam S
AS
Hicke
Linda
L
D000595:Amino Acid Sequence; D002352:Carrier Proteins / Q000378:metabolism*; D003598:Cytoskeletal Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D008840:Microfilament Proteins; D008969:Molecular Sequence Data; D009154:Mutation; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins / Q000378:metabolism*; D043743:Ubiquitin-Protein Ligase Complexes / Q000378:metabolism*; D014452:Ubiquitins / Q000378:metabolism; D018909:src Homology Domains
D002352:Carrier Proteins; D003598:Cytoskeletal Proteins; D056827:Endosomal Sorting Complexes Required for Transport; D008840:Microfilament Proteins; C082282:RVS167 protein, S cerevisiae; C082265:SLA1 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins; D043743:Ubiquitin-Protein Ligase Complexes; C469287:RSP5 protein, S cerevisiae