Feeding the machine: mechanisms of proteasome-catalyzed degradation of ubiquitinated proteins.
The proteasome plays a role in a myriad of intracellular processes from cell-cycle control to antigen presentation. Central to these processes is the targeting of selected proteins for proteasomal degradation via their conjugation to ubiquitin. The mechanisms by which the ubiquitin-dependent proteasomal proteolysis occurs can be divided into four steps: first, substrate protein recognition by its cognate E3 ubiquitin ligase; second, polyubiquitinated protein substrate recruitment to the proteasome; third, protein substrate deubiquitination; and four, proteolytic chamber pore opening/substrate translocation followed by proteolysis. Recent advances include the identification of novel E3 ubiquitin ligase recognition determinants, a new isopeptidase activity, and a better understanding of how the proteasome's axial channels are gated.
Crews
Craig M
CM
Departments of Molecular, Cell and Developmental Biology, Yale University, PO Box 208103, New Haven, CT 06520-8130, USA. craig.crews@yale.edu
D019759:Carbon-Nitrogen Lyases / Q000378:metabolism; D002384:Catalysis; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D006801:Humans; D009097:Multienzyme Complexes / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D011506:Proteins / Q000378:metabolism*; D013379:Substrate Specificity; D025801:Ubiquitin / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases / Q000378:metabolism
D009097:Multienzyme Complexes; D011506:Proteins; D025801:Ubiquitin; D044767:Ubiquitin-Protein Ligases; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex; D019759:Carbon-Nitrogen Lyases; C034300:isopeptidase