?
Ubiquitin-conjugating enzyme E2, catalytic (UBCc) domain of ubiquitin-conjugating enzyme E2 K and related proteins The E2J subfamily includes mammalian ubiquitin-conjugating enzymes E2 K (UBE2K/HIP2/LIG), yeast ubiquitin-conjugating enzyme E2 1 (UBC1), and plant ubiquitin-conjugating enzyme E2 27 (UBC27). They are ubiquitin-conjugating enzymes (EC 2.3.2.23) that accept ubiquitin from the E1 complex and catalyze the covalent attachment to other proteins. UBE2K is also called huntingtin-interacting protein 2 (HIP-2), ubiquitin-conjugating enzyme E2-25 kDa, or ubiquitin-conjugating enzyme E2(25K). In vitro, in the presence or absence of BRCA1-BARD1 E3 ubiquitin-protein ligase complex, UBE2K catalyzes the synthesis of 'Lys-48'-linked polyubiquitin chains. It does not transfer ubiquitin directly, but elongates monoubiquitinated substrate proteins. Saccharomyces cerevisiae UBC1, also called ubiquitin-conjugating enzyme E2-24 kDa, functions in the degradation of misfolded or regulated proteins localized in the endoplasmic reticulum (ER) lumen or membrane via the ubiquitin-proteasome system. It is a cognate E2 conjugating enzyme for the HRD1 ubiquitin ligase complex, which is part of the ERAD-L and ERAD-M pathways responsible for the rapid degradation of soluble lumenal and membrane proteins with misfolded lumenal domains (ERAD-L), or ER-membrane proteins with misfolded transmembrane domains (ERAD-M).
|