title: UbcH6 interacts with and ubiquitinates the SCA1 gene product ataxin-1.
abstract: UbcH6 is a member of an evolutionally conserved subfamily of E2 ubiquitin-conjugating enzymes. In this study, we report that UbcH6 interacts with and ubiquitinates ataxin-1, the spinocerebellar ataxia type 1 gene product. UbcH6 was identified as an ataxin-1-interacting protein using a yeast two-hybrid screen. UbcH6 co-immunoprecipitates and co-localizes with the ataxin-1 protein in the nucleus. Our binding assays showed that ataxin-1 interacts with UbcH6 through its AXH domain. Interestingly, UbcH6 could ubiquitinate ataxin-1 in the absence of an E3 ligase. The expression level of UbcH6 regulated the rate of ataxin-1 degradation. This study demonstrates that UbcH6 and ataxin-1 are E2-substrate cognate pairs in the ubiquitin-proteasome system.
authors.affiliation: Graduate School of Life Sciences and Biotechnology, Korea University, 1, 5ka, Anam-dong, Sungbuk-Ku, Seoul 136-701, Republic of Korea.
authors.forename: Sunghoi
authors.initials: S
authors.lastname: Hong
authors.forename: Soyeon
authors.initials: S
authors.lastname: Lee
authors.forename: Ssang-Goo
authors.initials: SG
authors.lastname: Cho
authors.forename: Seongman
authors.initials: S
authors.lastname: Kang
mesh_terms: D000067696:Ataxin-1; D000067528:Ataxins; D002460:Cell Line; D002467:Cell Nucleus / Q000737:chemistry / Q000378:metabolism; D006801:Humans; D047468:Immunoprecipitation; D009419:Nerve Tissue Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D009687:Nuclear Proteins / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex / Q000378:metabolism; D017434:Protein Structure, Tertiary; D020798:Two-Hybrid System Techniques; D044763:Ubiquitin-Conjugating Enzymes / Q000032:analysis / Q000235:genetics / Q000378:metabolism*; D054875:Ubiquitination
chemical_list: C000593749:ATXN1 protein, human; D000067696:Ataxin-1; D000067528:Ataxins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C489963:UBE2E1 protein, human; D044763:Ubiquitin-Conjugating Enzymes; D046988:Proteasome Endopeptidase Complex