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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Ataxin-1
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Ataxins
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Cell Line
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Cell Nucleus / chemistry
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Cell Nucleus / metabolism
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Humans
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Immunoprecipitation
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Nerve Tissue Proteins / analysis
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Nerve Tissue Proteins / genetics
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Nerve Tissue Proteins / metabolism*
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Nuclear Proteins / analysis
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Proteasome Endopeptidase Complex / metabolism
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Protein Structure, Tertiary
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Two-Hybrid System Techniques
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Ubiquitin-Conjugating Enzymes / analysis
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Ubiquitin-Conjugating Enzymes / genetics
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Ubiquitin-Conjugating Enzymes / metabolism*
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Ubiquitination*
Substances
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ATXN1 protein, human
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Ataxin-1
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Ataxins
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Nerve Tissue Proteins
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Nuclear Proteins
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UBE2E1 protein, human
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Ubiquitin-Conjugating Enzymes
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Proteasome Endopeptidase Complex