Ubiquitylation
Ubiquitylation, also known as ubiquitination, is a post-translational modification in which the small regulatory protein ubiquitin is covalently attached to substrate proteins. Ubiquitin is a 76-amino-acid polypeptide that can be attached as a single unit or as polyubiquitin chains, altering the fate and function of the substrate. This modification regulates protein stability, localization, activity, and interactions and is essential for numerous cellular processes.
Attachment proceeds through a three-enzyme cascade. An E1 activating enzyme uses ATP to form a thioester bond
Polyubiquitin chains containing lysine-48 are the best known signal for proteasomal degradation, while other linkages (such
Ubiquitylation is central to cell cycle control, DNA repair, immune signaling, and development. Dysregulation can contribute