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Crystal Structure of ScSkp1-ScCdc4-CPD peptide complexCrystal Structure of ScSkp1-ScCdc4-CPD peptide complex
Structural highlights
Function[SKP1_YEAST] Essential component of the E3 ubiquitin ligase complex SCF (SKP1-CUL1-F-box protein) ubiquitin ligase complex, which mediates the ubiquitination and subsequent proteasomal degradation of target proteins like phosphorylated SIC1. Participates in the attachment of chromosomes to the spindle. Acts as a regulatory component of the centromere DNA-binding protein complex CBF3, which is essential for chromosome segregation and movement of centromeres along microtubules. CBF3 is required for the recruitment of other kinetochore complexes to CEN DNA. It plays a role in the attachment of chromosomes to the spindle and binds selectively to a highly conserved DNA sequence called CDEIII, found in centromeres and in several promoters. The association of CBF3C with CBF3D and SGT1 is required for CBF3C activation and CBF3 assembly. SKP1/CBF3D could retrieve cyclins or cyclin-CDK-like proteins into the kinetochore thus providing cell cycle-regulated kinetochore activity. Involved in the regulation of methionine biosynthesis genes. Facilitates association of CDC53 with CDC4 and of ROY1 with YPT52.[1] [2] [3] [4] [5] [6] [7] [CDC4_YEAST] Substrate recognition component of a SCF (SKP1-CUL1-F-box protein) E3 ubiquitin-protein ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. Recognizes and binds to phosphorylated target proteins. Directs ubiquitination of the phosphorylated CDK inhibitor SIC1. Involved in the degradation of CDC6 together with CDC34/UBC3 and CDC53, and in restricting the degradation of FAR1 to the nucleus. Is essential for initiation of DNA replication and separation of the spindle pole bodies to form the poles of the mitotic spindle. It also plays a role in bud development, fusion of zygotic nuclei after conjugation and various aspects of sporulation. Required for HTA1-HTB1 locus transcription activation. Required for G1/S and G2/M transition.[8] [9] [10] [11] [12] [13] [14] [15] [16] Evolutionary ConservationCheck, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedCell cycle progression depends on precise elimination of cyclins and cyclin-dependent kinase (CDK) inhibitors by the ubiquitin system. Elimination of the CDK inhibitor Sic1 by the SCFCdc4 ubiquitin ligase at the onset of S phase requires phosphorylation of Sic1 on at least six of its nine Cdc4-phosphodegron (CPD) sites. A 2.7 A X-ray crystal structure of a Skp1-Cdc4 complex bound to a high-affinity CPD phosphopeptide from human cyclin E reveals a core CPD motif, Leu-Leu-pThr-Pro, bound to an eight-bladed WD40 propeller domain in Cdc4. The low affinity of each CPD motif in Sic1 reflects structural discordance with one or more elements of the Cdc4 binding site. Reengineering of Cdc4 to reduce selection against Sic1 sequences allows ubiquitination of lower phosphorylated forms of Sic1. These features account for the observed phosphorylation threshold in Sic1 recognition and suggest an equilibrium binding mode between a single receptor site in Cdc4 and multiple low-affinity CPD sites in Sic1. Structural basis for phosphodependent substrate selection and orientation by the SCFCdc4 ubiquitin ligase.,Orlicky S, Tang X, Willems A, Tyers M, Sicheri F Cell. 2003 Jan 24;112(2):243-56. PMID:12553912[17] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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