Enzymes of ubiquitination and deubiquitination.
Ubiquitination, the covalent attachment of the small protein modifier ubiquitin to a substrate protein is involved in virtually all cellular processes by mediating the regulated degradation of proteins. Aside from proteasomal degradation, ubiquitination plays important roles in transcriptional regulation, protein trafficking, including endocytosis and lysosomal targeting, and activation of kinases involved in signalling processes. A three-tiered enzymatic cascade consisting of E1 or ubiquitin-activating enzyme, E2 or ubiquitin-conjugating enzyme, and E3, or ubiquitin ligases, is necessary to achieve the many forms of ubiquitination known to date. In this chapter, we summarize the current knowledge on the enzymatic machinery necessary for ubiquitin activation and ligation, as well as its removal, and provide some insight into the complexity of regulatory processes governed by ubiquitination.
Department of Biomedicine, University Basel, Hebelstrasse 20, 4031 Basel, Switzerland.
Melanie
M
Neutzner
Albert
A
Neutzner
D000818:Animals; D006801:Humans; D011499:Protein Processing, Post-Translational; D025801:Ubiquitin / Q000378:metabolism*; D044764:Ubiquitin-Activating Enzymes / Q000378:metabolism; D044763:Ubiquitin-Conjugating Enzymes / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism; D054875:Ubiquitination
D025801:Ubiquitin; D044763:Ubiquitin-Conjugating Enzymes; D044767:Ubiquitin-Protein Ligases; D044764:Ubiquitin-Activating Enzymes