Health / Medical Topics |
E3 Ubiquitin Ligase
E3 Ubiquitin Ligases are ATP-dependent enzymes that catalyze the formation of a covalent bond between ubiquitous intracellular Ubiquitin proteins and other proteins, often to mark them for nonlysosomal proteasomal degradation or targeted transport. Ubiquitination requires sequential action of an activating enzyme (E1), a conjugating enzyme (E2), and a ligase (E3). Ubiquitin is coupled to protein by a peptide bond between the ubiquitin C-terminal glycine and protein lysine alpha-amino groups. Ubiquitination regulates protein degradation, chromatin remodeling, cell cycle progression, differentiation, gene expression, stress response, ribosome biogenesis, antigen presentation, apoptosis, signal transduction, transcriptional activation, biological clocks, receptor down regulation, and endocytosis. (NCI Thesaurus)