Fraction of newly synthesized proteins that are very rapidly degraded by the ubiquitin-proteasome system (UPS)

Range 6 - 30 %
Organism Eukaryotes
Reference Wang F, Durfee LA, Huibregtse JM. A cotranslational ubiquitination pathway for quality control of misfolded proteins. Mol Cell. 2013 May 9 50(3):368-78. doi: 10.1016/j.molcel.2013.03.009. p.368 right column top paragraph & p.376 right column bottom paragraphPubMed ID23583076
Primary Source S.B. Qian, M.F. Princiotta, J.R. Bennink, J.W. Yewdell, Characterization of rapidly degraded polypeptides in mammalian cells reveals a novel layer of nascent protein quality control, J. Biol. Chem., 281 (2006), pp. 392–400 DOI: 10.1074/jbc.M509126200 AND U. Schubert, L.C. Antón, J. Gibbs, C.C. Norbury, J.W. Yewdell, J.R. Bennink, Rapid degradation of a large fraction of newly synthesized proteins by proteasomes, Nature, 404 (2000), pp. 770–774 DOI: 10.1038/35008096PubMed ID16263705, 10783891
Comments P.368 right column top paragraph: "Surprisingly, between 6% and 30% of all eukaryotic, newly synthesized proteins are very rapidly degraded by the UPS (primary sources), suggesting that the UPS plays an important role in quality control of newly synthesized proteins." P.376 right column bottom paragraph: "Estimates of the fraction of newly synthesized proteins subject to rapid degradation in mammalian cells have varied from 6% to 30% (primary sources link ). While this range illustrates the need for better techniques for assessing the turnover of newly synthesized proteins (Yewdell and Nicchitta, 2006), these reports are generally consistent with [investigators’] finding that CTU [cotranslational ubiquitination] is a robust process in mammalian cells. While results presented here suggest that CTUA [cotranslational ubiquitination active translation complexes] is a component of a protein folding quality control system, the characteristics and recognition of nascent polypeptides with CTUS [cotranslational ubiquitination stalled complexes] and CTUA complexes clearly require further definition. Key questions to be addressed concern the identification of the enzymes and degrons involved in CTUS and CTUA, how the enzymes are localized to the translational machinery or nascent peptides, and, in the case of CTUA, the basis for protein fate decisions being made in the course of translation." See BNID 108154
Entered by Uri M
ID 113356