UBE2K (UBC1) Recombinant Protein

The protein encoded by this gene belongs to the ubiquitin-conjugating enzyme family. This protein interacts with RING finger proteins, and it can ubiquitinate huntingtin, the gene product for Huntington's disease. Known functions for this protein include a role in aggregate formation of expanded polyglutamine proteins and the suppression of apoptosis in polyglutamine diseases, a role in the dislocation of newly synthesized MHC class I heavy chains from the endoplasmic reticulum, and involvement in foam cell formation. Multiple transcript variants encoding different isoforms have been identified for this gene. [provided by RefSeq, Jul 2008]

Function: Accepts ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins. In vitro, in the presence or in the absence of BRCA1-BARD1 E3 ubiquitin-protein ligase complex, catalyzes the synthesis of 'Lys-48'-linked polyubiquitin chains. Does not transfer ubiquitin directly to but elongates monoubiquitinated substrate protein. Mediates the selective degradation of short-lived and abnormal proteins, such as the endoplasmic reticulum-associated degradation (ERAD) of misfolded lumenal proteins. Ubiquitinates huntingtin. May mediate foam cell formation by the suppression of apoptosis of lipid-bearing macrophages through ubiquitination and subsequence degradation of p53/TP53. Proposed to be involved in ubiquitination and proteolytic processing of NF-kappa-B; in vitro supports ubiquitination of NFKB1. In case of infection by cytomegaloviruses may be involved in the US11-dependent degradation of MHC class I heavy chains following their export from the ER to the cytosol. In case of viral infections may be involved in the HPV E7 protein-dependent degradation of RB1. Ref.1 Ref.2 Ref.3 Ref.9 Ref.12 Ref.13 Ref.15 Ref.16

Catalytic activity: ATP + ubiquitin + protein lysine = AMP + diphosphate + protein N-ubiquityllysine.

Pathway: Protein modification; protein ubiquitination.

Subunit structure: Interacts with RNF138/NARF. Interacts with BRCA1. Ref.9 Ref.13

Subcellular location: Cytoplasm

By similarity.

Tissue specificity: Expressed in all tissues tested, including spleen, thymus, prostate, testis, ovary, small intestine, colon, peripheral blood leukocytes, T-lymphocytes, monocytes, granulocytes and bone marrow mononuclear cells. Highly expressed in brain, with highest levels found in cortex and striatum and at lower levels in cerebellum and brainstem. Ref.1 Ref.2 Ref.3

Induction: By aggregated low-density lipoprotein. Ref.2 Ref.3

Post-translational modification: Sumoylation at Lys-14 impairs catalytic activity

By similarity.

Sequence similarities: Belongs to the ubiquitin-conjugating enzyme family.Contains 1 UBA domain.