title: ROC1, a homolog of APC11, represents a family of cullin partners with an associated ubiquitin ligase activity.
abstract: We have identified two highly conserved RING finger proteins, ROC1 and ROC2, that are homologous to APC11, a subunit of the anaphase-promoting complex. ROC1 and ROC2 commonly interact with all cullins while APC11 specifically interacts with APC2, a cullin-related APC subunit. YeastROC1 encodes an essential gene whose reduced expression resulted in multiple, elongated buds and accumulation of Sic1p and Cln2p. ROC1 and APC11 immunocomplexes can catalyze isopeptide ligations to form polyubiquitin chains in an E1- and E2-dependent manner. ROC1 mutations completely abolished their ligase activity without noticeable changes in associated proteins. Ubiquitination of phosphorylated I kappa B alpha can be catalyzed by the ROC1 immunocomplex in vitro. Hence, combinations of ROC/APC11 and cullin proteins proteins potentially constitute a wide variety of ubiquitin ligases.
authors.affiliation: Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill 27599, USA.
authors.forename: T
authors.initials: T
authors.lastname: Ohta
authors.forename: J J
authors.initials: JJ
authors.lastname: Michel
authors.forename: A J
authors.initials: AJ
authors.lastname: Schottelius
authors.forename: Y
authors.initials: Y
authors.lastname: Xiong
mesh_terms: D000595:Amino Acid Sequence; D064173:Anaphase-Promoting Complex-Cyclosome; D064198:Apc11 Subunit, Anaphase-Promoting Complex-Cyclosome; D064190:Apc2 Subunit, Anaphase-Promoting Complex-Cyclosome; D001483:Base Sequence; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002460:Cell Line; D044842:Cullin Proteins; D044783:F-Box Proteins; D000073979:F-Box-WD Repeat-Containing Protein 7; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics*; D006801:Humans; D008025:Ligases / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D010453:Peptide Synthases / Q000235:genetics* / Q000378:metabolism; D010641:Phenotype; D044843:SKP Cullin F-Box Protein Ligases; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins; D017386:Sequence Homology, Amino Acid; D043743:Ubiquitin-Protein Ligase Complexes; D044767:Ubiquitin-Protein Ligases; D014452:Ubiquitins / Q000378:metabolism
chemical_list: C080443:CDC4 protein, S cerevisiae; D018797:Cell Cycle Proteins; C100318:Cullin 1; D044842:Cullin Proteins; D044783:F-Box Proteins; D000073979:F-Box-WD Repeat-Containing Protein 7; C513273:FBXW7 protein, human; D005656:Fungal Proteins; D029701:Saccharomyces cerevisiae Proteins; D014452:Ubiquitins; D043743:Ubiquitin-Protein Ligase Complexes; C577351:ANAPC11 protein, human; C577346:APC2 protein, S cerevisiae; D064173:Anaphase-Promoting Complex-Cyclosome; D064198:Apc11 Subunit, Anaphase-Promoting Complex-Cyclosome; D064190:Apc2 Subunit, Anaphase-Promoting Complex-Cyclosome; D044843:SKP Cullin F-Box Protein Ligases; D044767:Ubiquitin-Protein Ligases; D008025:Ligases; D010453:Peptide Synthases