The ubiquitin-proteasome system and its role in ethanol-induced disorders


  • Terrence M. Donohue Jr

    Corresponding author
    1. Liver Study Unit, Department of Veterans Affairs Medical Center and the Departments of Internal Medicine and Biochemistry/Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Terrence M. Donohue Jr PhD, Liver Study Unit (151), Omaha VA Medical Center, 4101 Woolworth Avenue, Omaha, NE, 68105, USA. Tel: 402 346 8800, ext 3556; Fax: 402 449 0604; e-mail:


Abstract Some of the most fundamental yet important cellular activities such as cell division and gene expression are controlled by short-lived regulatory proteins. The levels of these proteins are controlled by their rates of degradation. Similarly, protein catabolism plays a crucial role in prolonging cellular life by destroying damaged proteins that are potentially cytotoxic. A major player in these catabolic reactions is the ubiquitin-proteasome system, a novel proteolytic system that has become the primary proteolytic pathway in eukaryotic cells. Ubiquitin-mediated proteolysis is now regarded as the major pathway by which most intracellular proteins are destroyed. Equally important, from a toxicological standpoint, is that the ubiquitin-proteasome system is also widely considered to be a cellular defense mechanism, since it is involved in the removal of damaged proteins generated by adduct formation and oxidative stress. This review describes the history and the components of the ubiquitin-proteasome system, its regulation and its role in pathological states, with the major emphasis on ethanol-induced organ injury. The available literature cited here deals mainly with the effects of ethanol consumption on the ubiquitin-proteasome pathway in the liver. However, since this proteolytic system is an essential pathway in all cells it is an attractive experimental model and therapeutic target in extrahepatic organs such as the brain and heart that are also affected by excessive alcohol consumption.