UbcH5c Active Protein

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 functions in the ubiquitination of the tumor-suppressor protein p53, which is induced by an E3 ubiquitin-protein ligase. Multiple spliced transcript variants have been found for this gene, but the full-length nature of some variants has not been determined. [provided by RefSeq, Jul 2008]

UBE2D3: Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro catalyzes 'Lys- 11'-, as well as 'Lys-48'-linked polyubiquitination. Cooperates with the E2 CDC34 and the SCF(FBXW11) E3 ligase complex for the polyubiquitination of NFKBIA leading to its subsequent proteasomal degradation. Acts as an initiator E2, priming the phosphorylated NFKBIA target at positions 'Lys-21' and/or 'Lys-22' with a monoubiquitin. Ubiquitin chain elongation is then performed by CDC34, building ubiquitin chains from the UBE2D3-primed NFKBIA- linked ubiquitin. Acts also as an initiator E2, in conjunction with RNF8, for the priming of PCNA. Monoubiquitination of PCNA, and its subsequent polyubiquitination, are essential events in the operation of the DNA damage tolerance (DDT) pathway that is activated after DNA damage caused by UV or chemical agents during S-phase. Associates with the BRCA1/BARD1 E3 ligase complex to perform ubiquitination at DNA damage sites following ionizing radiation leading to DNA repair. Targets DAPK3 for ubiquitination which influences promyelocytic leukemia protein nuclear body (PML- NB) formation in the nucleus. In conjunction with the MDM2 and TOPORS E3 ligases, functions ubiquitination of p53/TP53. Supports NRDP1-mediated ubiquitination and degradation of ERBB3 and of BRUCE which triggers apoptosis. In conjunction with the CBL E3 ligase, targets EGFR for polyubiquitination at the plasma membrane as well as during its internalization and transport on endosomes. In conjunction with the STUB1 E3 quality control E3 ligase, ubiquitinates unfolded proteins to catalyze their immediate destruction. Interacts with SCF (SKP1-CUL1-F-box protein) E3 ubiquitin ligase complex; when Cullin is neddylated, the interaction between the E2 and the SCF complex is strengthened. Interacts with DAPK3. Interacts with BRCA1; the DNA damage checkpoint promotes the association with BRCA1 after ionizing radiation. Interacts non- covalently with ubiquitin. Belongs to the ubiquitin-conjugating enzyme family. 3 isoforms of the human protein are produced by alternative splicing.

Protein type: Ubiquitin ligase; Ligase; Ubiquitin conjugating system; EC 6.3.2.19

Chromosomal Location of Human Ortholog: 4q24

Cellular Component: nucleoplasm; plasma membrane; endosome membrane; cytosol

Molecular Function: protein binding; ubiquitin-protein ligase activity; ATP binding; ligase activity

Biological Process: ubiquitin-dependent protein catabolic process; protein monoubiquitination; transcription initiation from RNA polymerase II promoter; proteasomal ubiquitin-dependent protein catabolic process; protein polyubiquitination; transcription, DNA-dependent; apoptosis; MyD88-independent toll-like receptor signaling pathway; protein modification process; protein ubiquitination; negative regulation of transcription from RNA polymerase II promoter; toll-like receptor 3 signaling pathway; DNA repair; BMP signaling pathway; transforming growth factor beta receptor signaling pathway; toll-like receptor signaling pathway; innate immune response; gene expression; negative regulation of interferon type I production; toll-like receptor 4 signaling pathway