View source for 8bya


==Cryo-EM structure of SKP1-SKP2-CKS1-CDK2-CyclinA-p27KIP1 Complex==
<StructureSection load='8bya' size='340' side='right'caption='[[8bya]], [[Resolution|resolution]] 3.38&Aring;' scene=''>
== Structural highlights ==
<table><tr><td colspan='2'>[[8bya]] is a 7 chain structure with sequence from [https://en.wikipedia.org/wiki/Homo_sapiens Homo sapiens]. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=8BYA OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=8BYA FirstGlance]. <br>
</td></tr><tr id='method'><td class="sblockLbl"><b>[[Empirical_models|Method:]]</b></td><td class="sblockDat" id="methodDat">Electron Microscopy, [[Resolution|Resolution]] 3.38&#8491;</td></tr>
<tr id='ligand'><td class="sblockLbl"><b>[[Ligand|Ligands:]]</b></td><td class="sblockDat" id="ligandDat"><scene name='pdbligand=TPO:PHOSPHOTHREONINE'>TPO</scene></td></tr>
<tr id='resources'><td class="sblockLbl"><b>Resources:</b></td><td class="sblockDat"><span class='plainlinks'>[https://proteopedia.org/fgij/fg.htm?mol=8bya FirstGlance], [http://oca.weizmann.ac.il/oca-bin/ocaids?id=8bya OCA], [https://pdbe.org/8bya PDBe], [https://www.rcsb.org/pdb/explore.do?structureId=8bya RCSB], [https://www.ebi.ac.uk/pdbsum/8bya PDBsum], [https://prosat.h-its.org/prosat/prosatexe?pdbcode=8bya ProSAT]</span></td></tr>
</table>
== Function ==
[https://www.uniprot.org/uniprot/CDK2_HUMAN CDK2_HUMAN] Serine/threonine-protein kinase involved in the control of the cell cycle; essential for meiosis, but dispensable for mitosis. Phosphorylates CTNNB1, USP37, p53/TP53, NPM1, CDK7, RB1, BRCA2, MYC, NPAT, EZH2. Interacts with cyclins A, B1, B3, D, or E. Triggers duplication of centrosomes and DNA. Acts at the G1-S transition to promote the E2F transcriptional program and the initiation of DNA synthesis, and modulates G2 progression; controls the timing of entry into mitosis/meiosis by controlling the subsequent activation of cyclin B/CDK1 by phosphorylation, and coordinates the activation of cyclin B/CDK1 at the centrosome and in the nucleus. Crucial role in orchestrating a fine balance between cellular proliferation, cell death, and DNA repair in human embryonic stem cells (hESCs). Activity of CDK2 is maximal during S phase and G2; activated by interaction with cyclin E during the early stages of DNA synthesis to permit G1-S transition, and subsequently activated by cyclin A2 (cyclin A1 in germ cells) during the late stages of DNA replication to drive the transition from S phase to mitosis, the G2 phase. EZH2 phosphorylation promotes H3K27me3 maintenance and epigenetic gene silencing. Phosphorylates CABLES1 (By similarity). Cyclin E/CDK2 prevents oxidative stress-mediated Ras-induced senescence by phosphorylating MYC. Involved in G1-S phase DNA damage checkpoint that prevents cells with damaged DNA from initiating mitosis; regulates homologous recombination-dependent repair by phosphorylating BRCA2, this phosphorylation is low in S phase when recombination is active, but increases as cells progress towards mitosis. In response to DNA damage, double-strand break repair by homologous recombination a reduction of CDK2-mediated BRCA2 phosphorylation. Phosphorylation of RB1 disturbs its interaction with E2F1. NPM1 phosphorylation by cyclin E/CDK2 promotes its dissociates from unduplicated centrosomes, thus initiating centrosome duplication. Cyclin E/CDK2-mediated phosphorylation of NPAT at G1-S transition and until prophase stimulates the NPAT-mediated activation of histone gene transcription during S phase. Required for vitamin D-mediated growth inhibition by being itself inactivated. Involved in the nitric oxide- (NO) mediated signaling in a nitrosylation/activation-dependent manner. USP37 is activated by phosphorylation and thus triggers G1-S transition. CTNNB1 phosphorylation regulates insulin internalization.<ref>PMID:10499802</ref> <ref>PMID:11051553</ref> <ref>PMID:10995386</ref> <ref>PMID:10995387</ref> <ref>PMID:10884347</ref> <ref>PMID:11113184</ref> <ref>PMID:15800615</ref> <ref>PMID:18372919</ref> <ref>PMID:20147522</ref> <ref>PMID:20079829</ref> <ref>PMID:20935635</ref> <ref>PMID:20195506</ref> <ref>PMID:19966300</ref> <ref>PMID:21262353</ref> <ref>PMID:21596315</ref> <ref>PMID:21319273</ref> <ref>PMID:17495531</ref> 
<div style="background-color:#fffaf0;">
== Publication Abstract from PubMed ==
p27KIP1 (cyclin-dependent kinase inhibitor 1B, p27) is a member of the CIP/KIP family of CDK (cyclin dependent kinase) regulators that inhibit cell cycle CDKs. p27 phosphorylation by CDK1/2, signals its recruitment to the SCF(SKP2) (S-phase kinase associated protein 1 (SKP1)-cullin-SKP2) E3 ubiquitin ligase complex for proteasomal degradation. The nature of p27 binding to SKP2 and CKS1 was revealed by the SKP1-SKP2-CKS1-p27 phosphopeptide crystal structure. Subsequently, a model for the hexameric CDK2-cyclin A-CKS1-p27-SKP1-SKP2 complex was proposed by overlaying an independently determined CDK2-cyclin A-p27 structure. Here we describe the experimentally determined structure of the isolated CDK2-cyclin A-CKS1-p27-SKP1-SKP2 complex at 3.4 A global resolution using cryogenic electron microscopy. This structure supports previous analysis in which p27 was found to be structurally dynamic, transitioning from disordered to nascent secondary structure on target binding. We employed 3D variability analysis to further explore the conformational space of the hexameric complex and uncovered a previously unidentified hinge motion centred on CKS1. This flexibility gives rise to open and closed conformations of the hexameric complex that we propose may contribute to p27 regulation by facilitating recognition with SCF(SKP2). This 3D variability analysis further informed particle subtraction and local refinement approaches to enhance the local resolution of the complex.

Cryo-EM structure of SKP1-SKP2-CKS1 in complex with CDK2-cyclin A-p27KIP1.,Rowland RJ, Heath R, Maskell D, Thompson RF, Ranson NA, Blaza JN, Endicott JA, Noble MEM, Salamina M Sci Rep. 2023 Jul 3;13(1):10718. doi: 10.1038/s41598-023-37609-9. PMID:37400515<ref>PMID:37400515</ref>

From MEDLINE&reg;/PubMed&reg;, a database of the U.S. National Library of Medicine.<br>
</div>
<div class="pdbe-citations 8bya" style="background-color:#fffaf0;"></div>
== References ==
<references/>
__TOC__
</StructureSection>
[[Category: Homo sapiens]]
[[Category: Large Structures]]
[[Category: Endicott JA]]
[[Category: Noble ME]]
[[Category: Rowland RJ]]
[[Category: Salamina M]]