Ubiquitin-Dependent Protein Degradation
Intracellular protein levels are controlled by protein synthesis and degradation. One major proteolytic pathway of eukaryotes requires the covalent attachment of ubiquitin, a small (8.5 kDa) and highly conserved protein, to proteolytic substrates prior to degradation (for reviews see Hershko 1991; Finley and Chau 1991; Jentsch et al. 1991, Jentsch 1992a; Jentsch 1992b). This pathway is highly selective and mediates the elimination of abnormal proteins and controls the half-lives of some regulatory proteins. Known targets include transcriptional regulators (Hochstrasser et al. 1991) p53 (Scheffner et al. 1990) and cyclins (Glotzer et al. 1991). In a number of eukaryotes, cyclin degradation is required to exit from mitosis.
KeywordsSpindle Pole Body Proteolytic Substrate Intracellular Protein Level Cyclin Degradation Enzyme UBC4
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