title: The U-box ligase carboxyl-terminus of Hsc 70-interacting protein ubiquitylates Epsin.
abstract: Epsin is an endocytic adaptor protein involved in the regulation of clathrin-dependent endocytosis. We and others have demonstrated that Epsin is ubiquitylated in cells and requires its ubiquitin interacting motifs (UIMs) for this modification. To further elucidate the mechanism of Epsin ubiquitylation, we initiated studies to identify the E3 ligase(s) that modifies Epsin. In this study, we discovered that the U-box ubiquitin ligase carboxyl-terminus of Hsc70 interacting protein (CHIP) ubiquitylated Epsin. Using an in vitro ubiquitylation assay, we demonstrate that CHIP specifically ubiquitylated Epsin in a UIM-dependent manner. Furthermore, overexpression of CHIP in cells increased Epsin ubiquitylation also in a UIM-dependent manner. Together, these data provide evidence that CHIP functions to ubiquitylate the endocytic protein Epsin.
authors.affiliation: Laboratory of Signal Transduction, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, NC 27709, USA.
authors.forename: Yoav E
authors.initials: YE
authors.lastname: Timsit
authors.forename: Stephanie L H
authors.initials: SL
authors.lastname: Miller
authors.forename: Robert P
authors.initials: RP
authors.lastname: Mohney
authors.forename: John P
authors.initials: JP
authors.lastname: O'Bryan
mesh_terms: D033942:Adaptor Proteins, Vesicular Transport; D001665:Binding Sites; D002460:Cell Line; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D007668:Kidney / Q000196:embryology / Q000378:metabolism*; D011485:Protein Binding; D013329:Structure-Activity Relationship; D025801:Ubiquitin / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism*; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000378:metabolism*
chemical_list: D033942:Adaptor Proteins, Vesicular Transport; D050883:HSC70 Heat-Shock Proteins; D018840:HSP70 Heat-Shock Proteins; C494371:HSPA8 protein, human; D025801:Ubiquitin; D033921:Vesicular Transport Proteins; C114154:epsin; D044767:Ubiquitin-Protein Ligases