NCBI Summary:
The modification of proteins with ubiquitin is an important cellular mechanism for targeting abnormal or short-lived proteins for degradation. Ubiquitination involves at least three classes of enzymes: ubiquitin-activating enzymes, or E1s, ubiquitin-conjugating enzymes, or E2s, and ubiquitin-protein ligases, or E3s. This gene encodes a member of the E2 ubiquitin-conjugating enzyme family. This enzyme is closely related to a stimulator of iron transport (SFT), and is up-regulated in hereditary hemochromatosis. It also functions in the ubiquitination of the tumor-suppressor protein p53 and the hypoxia-inducible transcription factor HIF1alpha by interacting with the E1 ubiquitin-activating enzyme and the E3 ubiquitin-protein ligases.
General function
Chromosome organization
Comment
Cellular localization
Nuclear
Comment
Ovarian function
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Expression regulated by
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Ovarian localization
Oocyte
Comment
Caenorhabditis elegans UBC-2 functions with the anaphase-promoting complex but also has other activities.
Frazier T, et al .
The anaphase-promoting complex or cyclosome (APC/C) is a multi-subunit ubiquitin ligase that regulates the eukaryotic cell cycle. APC/C belongs to the RING finger class of ubiquitin ligases that function by interacting with a ubiquitin-conjugating enzyme (Ubc), thus inciting the Ubc to transfer ubiquitin onto a target protein. Extensive studies with APC/C in other organisms have identified several possible Ubcs that might function as partners for APC/C. This report presents phenotypic and biochemical evidence showing that, in Caenorhabditis elegans, UBC-2 interacts specifically with the APC/C. This conclusion is based on three lines of evidence: first, the RNAi phenotype of ubc-2 is indistinguishable from RNAi phenotypes of APC/C subunits; second, RNAi of ubc-2 but not other Ubcs enhances the phenotype of hypomorphic APC/C mutants; third, purified UBC-2 and APC-11, the RING finger subunit of the APC/C, show robust ubiquitination activity in in vitro assays. APC-11 interaction is specific for UBC-2 as ubiquitination is not seen when APC-11 is combined other C. elegans Ubcs. As expected from the Ubc that functions with the APC/C, ubc-2(RNAi) produces metaphase blocks in both mitotic germ cells and in meiotic divisions of post-fertilization oocytes. In addition, ubc-2(RNAi) results in two germline phenotypes that appear to be unrelated to the APC/C: an expanded transition zone indicative of a pre-pachytene meiotic arrest and endo-reduplicated oocytes indicative of a problem in ovulation or oocyte-soma interactions.