title: A 26 S protease subunit that binds ubiquitin conjugates.
abstract: Ubiquitin-mediated proteolysis provides an important mechanism for regulating a variety of cellular processes. Ubiquitin-conjugated proteins are degraded by a 26 S protease that contains more than 30 different subunits. Of these, a single 50-kDa polypeptide, subunit 5, specifically binds ubiquitin-lysozyme conjugates. Binding is inhibited by short polymeric chains of ubiquitin but not by ubiquitin monomers or by lysozyme. In addition, subunit 5 binds free ubiquitin chains with efficient association requiring at least four ubiquitins. Thus, proteins conjugated to polymers of ubiquitin may be selected for degradation by a single subunit of the 26 S protease complex.
authors.affiliation: Department of Biochemistry, University of Utah School of Medicine, Salt lake City 84132.
authors.forename: Q
authors.initials: Q
authors.lastname: Deveraux
authors.forename: V
authors.initials: V
authors.lastname: Ustrell
authors.forename: C
authors.initials: C
authors.lastname: Pickart
authors.forename: M
authors.initials: M
authors.lastname: Rechsteiner
mesh_terms: D001667:Binding, Competitive; D006801:Humans; D010447:Peptide Hydrolases / Q000378:metabolism*; D046988:Proteasome Endopeptidase Complex; D014452:Ubiquitins / Q000378:metabolism*
chemical_list: D014452:Ubiquitins; D010447:Peptide Hydrolases; D046988:Proteasome Endopeptidase Complex; C061553:ATP dependent 26S protease