title: Role of Hcn1 and its phosphorylation in fission yeast anaphase-promoting complex/cyclosome function.
abstract: The anaphase-promoting complex/cyclosome (APC/C) is a conserved multisubunit ubiquitin ligase required for the degradation of key cell cycle regulators. The APC/C becomes active at the metaphase/anaphase transition and remains active during G(1) phase. One mechanism linked to activation of the APC/C is phosphorylation. Although many sites of mitotic phosphorylation have been identified in core components of the APC/C, the consequence of any individual phosphorylation event has not been elucidated in vivo. In this study, we show that Hcn1 is an essential core component of the fission yeast APC/C and is critical for maintaining complex integrity. Moreover, Hcn1 is a phosphoprotein in vivo. Phosphorylation of Hcn1 occurs at a single Cdk1 site in vitro and in vivo. Mutation of this site to alanine, but not aspartic acid, compromises APC/C function and leads to a specific defect in the completion of cell division.
authors.affiliation: Howard Hughes Medical Institute and the Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA.
authors.forename: Hyun-Joo
authors.initials: HJ
authors.lastname: Yoon
authors.forename: Anna
authors.initials: A
authors.lastname: Feoktistova
authors.forename: Jun-Song
authors.initials: JS
authors.lastname: Chen
authors.forename: Jennifer L
authors.initials: JL
authors.lastname: Jennings
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Link
authors.forename: Kathleen L
authors.initials: KL
authors.lastname: Gould
mesh_terms: D000409:Alanine / Q000378:metabolism; D019943:Amino Acid Substitution; D064173:Anaphase-Promoting Complex-Cyclosome; D018797:Cell Cycle Proteins / Q000235:genetics; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D016195:G2 Phase; D017353:Gene Deletion; D049452:Green Fluorescent Proteins / Q000378:metabolism; D010766:Phosphorylation; D012097:Repressor Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics / Q000378:metabolism*; D029702:Schizosaccharomyces pombe Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D043743:Ubiquitin-Protein Ligase Complexes / Q000502:physiology*
chemical_list: D018797:Cell Cycle Proteins; D005656:Fungal Proteins; D012097:Repressor Proteins; D029702:Schizosaccharomyces pombe Proteins; C577464:hcn1 protein, S pombe; D049452:Green Fluorescent Proteins; D043743:Ubiquitin-Protein Ligase Complexes; D064173:Anaphase-Promoting Complex-Cyclosome; D000409:Alanine