title: Protein interaction analysis of SCF ubiquitin E3 ligase subunits from Arabidopsis.
abstract: Ubiquitin E3 ligases are a diverse family of protein complexes that mediate the ubiquitination and subsequent proteolytic turnover of proteins in a highly specific manner. Among the several classes of ubiquitin E3 ligases, the Skp1-Cullin-F-box (SCF) class is generally comprised of three 'core' subunits: Skp1 and Cullin, plus at least one F-box protein (FBP) subunit that imparts specificity for the ubiquitination of selected target proteins. Recent genetic and biochemical evidence in Arabidopsis thaliana suggests that post-translational turnover of proteins mediated by SCF complexes is important for the regulation of diverse developmental and environmental response pathways. In this report, we extend upon a previous annotation of the Arabidopsis Skp1-like (ASK) and FBP gene families to include the Cullin family of proteins. Analysis of the protein interaction profiles involving the products of all three gene families suggests a functional distinction between ASK proteins in that selected members of the protein family interact generally while others interact more specifically with members of the F-box protein family. Analysis of the interaction of Cullins with FBPs indicates that CUL1 and CUL2, but not CUL3A, persist as components of selected SCF complexes, suggesting some degree of functional specialization for these proteins. Yeast two-hybrid analyses also revealed binary protein interactions between selected members of the FBP family in Arabidopsis. These and related results are discussed in terms of their implications for subunit composition, stoichiometry and functional diversity of SCF complexes in Arabidopsis.
authors.affiliation: Gene Expression Group, NRC Plant Biotechnology Institute, 110 Gymnasium Place, Saskatoon, SK, Canada S7N-0W9.
authors.forename: Eddy P
authors.initials: EP
authors.lastname: Risseeuw
authors.forename: Timothy E
authors.initials: TE
authors.lastname: Daskalchuk
authors.forename: Travis W
authors.initials: TW
authors.lastname: Banks
authors.forename: Enwu
authors.initials: E
authors.lastname: Liu
authors.forename: Julian
authors.initials: J
authors.lastname: Cotelesage
authors.forename: Hanjo
authors.initials: H
authors.lastname: Hellmann
authors.forename: Mark
authors.initials: M
authors.lastname: Estelle
authors.forename: David E
authors.initials: DE
authors.lastname: Somers
authors.forename: William L
authors.initials: WL
authors.lastname: Crosby
mesh_terms: D000595:Amino Acid Sequence; D017360:Arabidopsis / Q000235:genetics / Q000378:metabolism*; D029681:Arabidopsis Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005801:Genes, Homeobox; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D010453:Peptide Synthases / Q000737:chemistry / Q000378:metabolism*; D010802:Phylogeny; D010940:Plant Proteins / Q000378:metabolism; D011485:Protein Binding; D021122:Protein Subunits / Q000737:chemistry / Q000378:metabolism; D044843:SKP Cullin F-Box Protein Ligases; D016415:Sequence Alignment
chemical_list: C120363:ASK1 protein, Arabidopsis; D029681:Arabidopsis Proteins; D010940:Plant Proteins; D021122:Protein Subunits; C484058:ASK2 protein, Arabidopsis; D044843:SKP Cullin F-Box Protein Ligases; D010453:Peptide Synthases