title: Prb1 Protease Activity Is Required for Its Recognition by the F-Box Protein Saf1.
abstract: The SCF ubiquitin ligase associates with substrates through its F-box protein adaptor. Substrates are typically recognized through a defined phosphodegron. Here, we characterize the interaction of the F-box protein Saf1 with Prb1, one of its vacuolar protease substrates. We show that Saf1 binds the mature protein but ubiquitinates only the zymogen precursor. The ubiquitinated lysine was found to be in a peptide eliminated from the mature protein. Mutations that eliminate the catalytic activity of Prb1, or the related substrate Prc1, block Saf1 targeting of the zymogen precursor. Our data suggest that Saf1 does not require a conventional degron as do other F-box proteins but instead recognizes the catalytic site itself.
authors.affiliation: †Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158, United States.
authors.forename: Kevin G
authors.initials: KG
authors.lastname: Mark
authors.affiliation: †Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158, United States.
authors.forename: Fernando
authors.initials: F
authors.lastname: Meza-Gutierrez
authors.affiliation: ‡Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158, United States.
authors.forename: Jeffrey R
authors.initials: JR
authors.lastname: Johnson
authors.affiliation: ‡Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158, United States.
authors.forename: Billy W
authors.initials: BW
authors.lastname: Newton
authors.affiliation: ‡Department of Cellular and Molecular Pharmacology, University of California, San Francisco, California 94158, United States.
authors.forename: Nevan J
authors.initials: NJ
authors.lastname: Krogan
authors.affiliation: †Department of Biochemistry and Biophysics, University of California, San Francisco, California 94158, United States.
authors.forename: David P
authors.initials: DP
authors.lastname: Toczyski
mesh_terms: D010450:Endopeptidases / Q000737:chemistry* / Q000502:physiology; D044783:F-Box Proteins / Q000737:chemistry*; D011485:Protein Binding; D059748:Proteolysis; D012441:Saccharomyces cerevisiae / Q000201:enzymology*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000502:physiology
chemical_list: D044783:F-Box Proteins; D029701:Saccharomyces cerevisiae Proteins; C512528:Saf1 protein, S cerevisiae; D010450:Endopeptidases; C000598835:PRB1 protein, S cerevisiae