In vivo function of the proteasome in the ubiquitin pathway.
A major eukaryotic proteolytic system is known to require the covalent attachment of ubiquitin to substrates prior to their degradation, yet the proteinase involved remains poorly defined. The proteasome, a large conserved multi-subunit protein complex of the cytosol and the nucleus, has been implicated in a variety of cellular functions. It is shown here that a yeast mutant with a defective proteasome fails to degrade proteins which are subject to ubiquitin-dependent proteolysis in wild-type cells. Thus, the proteasome is part of the ubiquitin system and mediates the degradation of ubiquitin-protein conjugates in vivo.
Seufert
W
W
Friedrich-Miescher-Laboratorium der Max-Planck-Gesellschaft, Tübingen, Germany.
Jentsch
S
S
D001483:Base Sequence; D002467:Cell Nucleus / Q000201:enzymology; D003546:Cysteine Endopeptidases / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000201:enzymology; D007700:Kinetics; D008969:Molecular Sequence Data; D009097:Multienzyme Complexes / Q000235:genetics / Q000378:metabolism*; D016297:Mutagenesis, Site-Directed; D009838:Oligodeoxyribonucleotides; D016133:Polymerase Chain Reaction; D046988:Proteasome Endopeptidase Complex; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D014452:Ubiquitins / Q000235:genetics / Q000378:metabolism*; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D009097:Multienzyme Complexes; D009838:Oligodeoxyribonucleotides; D011993:Recombinant Fusion Proteins; D014452:Ubiquitins; D001616:beta-Galactosidase; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex