UBE2K
Description
The UBE2K (ubiquitin conjugating enzyme E2 K) is a protein-coding gene located on chromosome 4.
UBE2K, also known as E2 ubiquitin-conjugating enzyme K, plays a crucial role in the ubiquitin proteasome system (UPS) by facilitating the attachment of ubiquitin to target proteins. It receives ubiquitin from the E1 complex and catalyzes its covalent attachment to other proteins, contributing to the formation of 'Lys-48'-linked polyubiquitin chains. While UBE2K does not directly transfer ubiquitin to substrates, it elongates pre-existing monoubiquitinated proteins, promoting their degradation. This activity is essential for the selective removal of short-lived and abnormal proteins, such as those undergoing endoplasmic reticulum-associated degradation (ERAD) of misfolded lumenal proteins. UBE2K also directly ubiquitinates huntingtin, a protein associated with Huntington's disease. Additionally, UBE2K may contribute to foam cell formation by suppressing apoptosis in lipid-bearing macrophages, a process potentially mediated by the ubiquitination and subsequent degradation of p53/TP53. UBE2K is implicated in the ubiquitination and proteolytic processing of NF-kappa-B, with in vitro studies supporting its role in the ubiquitination of NFKB1. Furthermore, UBE2K may be involved in the degradation of MHC class I heavy chains during cytomegalovirus infection, a process dependent on the viral protein US11. In viral infections, UBE2K could also participate in the HPV E7 protein-dependent degradation of RB1.
UBE2K is also known as E2-25K, HIP2, HYPG, LIG, UBC1.