title: Cooperative organization in a macromolecular complex.
abstract: The mechanism of assembly of multiprotein complexes and the subsequent organization of activity are not well understood. Here we report the application of biophysical tools to investigate the relationship between structure and function in protein assemblies. We used as a model system the SCF(Skp2) complex that targets p27(Kip1) for ubiquitination and subsequent degradation; this process requires an adapter protein, Cks1. By dissecting the interactions between the different subunits we show that the properties of Cks1 are highly context dependent, and its activity is acquired only when the complex is fully assembled. The results provide insights into the central role of small adapters in macromolecular assembly and explain their high sequence conservation. Simultaneous and synergistic binding of multiple subunits in a complex provides the specificity and control required before the key cell-cycle regulator p27 is committed to degradation.
authors.affiliation: MRC Centre for Protein Engineering, Hills Road, Cambridge CB2 2QH, UK.
authors.forename: Markus A
authors.initials: MA
authors.lastname: Seeliger
authors.forename: Sadie E
authors.initials: SE
authors.lastname: Breward
authors.forename: Assaf
authors.initials: A
authors.lastname: Friedler
authors.forename: Oliver
authors.initials: O
authors.lastname: Schon
authors.forename: Laura S
authors.initials: LS
authors.lastname: Itzhaki
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000596:Amino Acids / Q000737:chemistry; D016880:Anisotropy; D001665:Binding Sites; D002151:Calorimetry; D018797:Cell Cycle Proteins / Q000737:chemistry*; D050760:Cyclin-Dependent Kinase Inhibitor p27; D004305:Dose-Response Relationship, Drug; D007700:Kinetics; D046911:Macromolecular Substances; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase; D008958:Models, Molecular; D009154:Mutation; D010748:Phosphopeptides / Q000737:chemistry; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D044786:S-Phase Kinase-Associated Proteins; D012441:Saccharomyces cerevisiae / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry*; D015398:Signal Transduction; D013050:Spectrometry, Fluorescence; D013329:Structure-Activity Relationship; D013816:Thermodynamics; D025521:Tumor Suppressor Proteins / Q000737:chemistry*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000596:Amino Acids; C081185:CKS1 protein, S cerevisiae; D018797:Cell Cycle Proteins; D046911:Macromolecular Substances; D010748:Phosphopeptides; D044786:S-Phase Kinase-Associated Proteins; D029701:Saccharomyces cerevisiae Proteins; D025521:Tumor Suppressor Proteins; D050760:Cyclin-Dependent Kinase Inhibitor p27; D017038:Mannosyl-Glycoprotein Endo-beta-N-Acetylglucosaminidase