Ciechanover A
Department of Biochemistry, Rappaport Institute for Research in the Medical Sciences, Haifa, Israel.
J Basic Clin Physiol Pharmacol. 1991 Jul-Sep;2(3):141-59. doi: 10.1515/jbcpp.1991.2.3.141.
Degradation of proteins by the ubiquitin system involves several discrete steps. Initially, multiple molecules of ubiquitin are covalently conjugated to the target substrate in an energy-requiring reaction. The protein thus marked is degraded by a specific ATP-dependent protease, and free and reutilizable ubiquitin is released. In this review we discuss the mechanisms involved in ubiquitin activation, selection of substrates for conjugation, and subsequent degradation of ubiquitin-conjugated proteins in the cell-free system. In addition, we summarize briefly what is currently known of the physiological roles of the ubiquitin system in vivo.
