Intracellular proteins are targeted for degradation by the covalent attachment of chains of the small protein ubiquitin; a process known as ubiquitylation. Many proteins are phosphorylated prior to ubiquitylation, and therefore ubiquitylation and degradation of these proteins is regulated by kinase activity and signalling cascades. Many ubiquitylated proteins are degraded by the 26 S proteasome complex, which is found in the cytosol and nucleus. The 26 S proteasome consists of a 20 S core with proteolytic activity and 18 S regulatory complexes containing ATPases and ubiquitin-chain-binding proteins. Proteins degraded by the ubiquitin-proteasome pathway include cyclins and other regulators of the cell cycle, and transcription factors. Abnormal polypeptides are also degraded by the ubiquitin pathway, including abnormal polypeptides in the endoplasmic reticulum, which are translocated back out of the endoplasmic reticulum prior to ubiquitylation and degradation by the proteasome. The ubiquitin-proteasome pathway is implicated in numerous diseases including cancer and neurodegenerative diseases.
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Review Article| October 01 2002
The ubiquitin-proteasome pathway of intracellular proteolysis
Fergus J Doherty ;
Simon Dawson ;
R John Mayer
R John Mayer 1
1Laboratory of Intracellular Proteolysis, School of Biomedical Sciences, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, U.K.
1To whom correspondence should be addressed (e-mail: email@example.com).
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Essays Biochem (2002) 38: 51–63.
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Nigel M. Hooper, Fergus J Doherty, Simon Dawson, R John Mayer; The ubiquitin-proteasome pathway of intracellular proteolysis. Essays Biochem 1 October 2002; 38 51–63. doi: https://doi.org/10.1042/bse0380051
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