title: The destruction box of the cyclin Clb2 binds the anaphase-promoting complex/cyclosome subunit Cdc23.
abstract: Properly regulated cyclin proteolysis is critical for normal cell cycle progression. A nine-amino acid peptide motif called the destruction box (D box) is present at the N terminus of the yeast mitotic cyclins. This short sequence is required for cyclin ubiquitination and subsequent proteolysis. The anaphase-promoting complex/cyclosome (APC/C) is a multisubunit E3 required for cyclin ubiquitination. We have tested the D box of five mitotic cyclins for interaction with six APC/C subunits. The APC/C subunit Cdc23, but not five other subunits tested, interacted by two-hybrid analysis with the N terminus of wild-type Clb2. None of these subunits interacted with the N termini of the cyclins Clb1, Clb3, or Clb5. Mutations in the D box sequences of Clb2 inhibited interaction with Cdc23 both in vivo and in vitro. Our results provide the first evidence for a direct interaction between an APC/C substrate (Clb2) and an APC/C subunit (Cdc23).
authors.affiliation: Howard Hughes Medical Institute and Department of Genetics, University of Pennsylvania Medical School, Philadelphia, PA 19104, USA.
authors.forename: Malcolm A
authors.initials: MA
authors.lastname: Meyn
authors.forename: Patricia G
authors.initials: PG
authors.lastname: Melloy
authors.forename: Jie
authors.initials: J
authors.lastname: Li
authors.forename: Sandra L
authors.initials: SL
authors.lastname: Holloway
mesh_terms: D020816:Amino Acid Motifs; D064173:Anaphase-Promoting Complex-Cyclosome; D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; D001665:Binding Sites; D018797:Cell Cycle Proteins / Q000378:metabolism*; D019926:Cyclin B / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008025:Ligases / Q000737:chemistry / Q000378:metabolism*; D009154:Mutation; D011485:Protein Binding; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D020798:Two-Hybrid System Techniques; D043743:Ubiquitin-Protein Ligase Complexes
chemical_list: D064196:Apc8 Subunit, Anaphase-Promoting Complex-Cyclosome; C577441:CDC23 protein, S cerevisiae; C093749:CLB2 protein, S cerevisiae; D018797:Cell Cycle Proteins; D019926:Cyclin B; D005656:Fungal Proteins; D021122:Protein Subunits; D029701:Saccharomyces cerevisiae Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D008025:Ligases