title: Identification of Candidate Cyclin-dependent kinase 1 (Cdk1) Substrates in Mitosis by Quantitative Phosphoproteomics.
abstract: Cyclin-dependent kinase 1 (Cdk1) is an essential regulator of many mitotic processes including the reorganization of the cytoskeleton, chromosome segregation, and formation and separation of daughter cells. Deregulation of Cdk1 activity results in severe defects in these processes. Although the role of Cdk1 in mitosis is well established, only a limited number of Cdk1 substrates have been identified in mammalian cells. To increase our understanding of Cdk1-dependent phosphorylation pathways in mitosis, we conducted a quantitative phosphoproteomics analysis in mitotic HeLa cells using two small molecule inhibitors of Cdk1, Flavopiridol and RO-3306. In these analyses, we identified a total of 24,840 phosphopeptides on 4,273 proteins, of which 1,215 phosphopeptides on 551 proteins were significantly reduced by 2.5-fold or more upon Cdk1 inhibitor addition. Comparison of phosphopeptide quantification upon either inhibitor treatment revealed a high degree of correlation (R(2) value of 0.87) between the different datasets. Motif enrichment analysis of significantly regulated phosphopeptides revealed enrichment of canonical Cdk1 kinase motifs. Interestingly, the majority of proteins identified in this analysis contained two or more Cdk1 inhibitor-sensitive phosphorylation sites, were highly connected with other candidate Cdk1 substrates, were enriched at specific subcellular structures, or were part of protein complexes as identified by the CORUM database. Furthermore, candidate Cdk1 substrates were enriched in G2 and M phase-specific genes. Finally, we validated a subset of candidate Cdk1 substrates by in vitro kinase assays. Our findings provide a valuable resource for the cell signaling and mitosis research communities and greatly increase our knowledge of Cdk1 substrates and Cdk1-dependent signaling pathways.
authors.affiliation: From the ‡Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755;
authors.forename: Adam
authors.initials: A
authors.lastname: Petrone
authors.affiliation: §Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire 03756;
authors.forename: Mark E
authors.initials: ME
authors.lastname: Adamo
authors.affiliation: ¶Department of Genetics, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755.
authors.forename: Chao
authors.initials: C
authors.lastname: Cheng
authors.affiliation: From the ‡Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, New Hampshire 03755; §Norris Cotton Cancer Center, Geisel School of Medicine at Dartmouth, Lebanon, New Hampshire 03756; arminja.n.kettenbach@dartmouth.edu.
authors.forename: Arminja N
authors.initials: AN
authors.lastname: Kettenbach
mesh_terms: D016203:CDC2 Protein Kinase; D002853:Chromatography, Liquid; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D005419:Flavonoids / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D006367:HeLa Cells; D006801:Humans; D008938:Mitosis; D010750:Phosphoproteins / Q000187:drug effects / Q000378:metabolism*; D010880:Piperidines / Q000494:pharmacology; D060066:Protein Interaction Maps; D040901:Proteomics / Q000379:methods*; D011804:Quinolines / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects; D054852:Small Molecule Libraries / Q000494:pharmacology*; D053719:Tandem Mass Spectrometry; D013844:Thiazoles / Q000494:pharmacology
chemical_list: D005419:Flavonoids; D010750:Phosphoproteins; D010880:Piperidines; D011804:Quinolines; C512984:RO 3306; D054852:Small Molecule Libraries; D013844:Thiazoles; C077990:alvocidib; D016203:CDC2 Protein Kinase; C528899:CDK1 protein, human; D018844:Cyclin-Dependent Kinases