CKS1/YBR135W Summary Help

Standard Name CKS1 1
Systematic Name YBR135W
Feature Type ORF, Verified
Description Cyclin-dependent protein kinase regulatory subunit and adaptor; interacts with Cdc28p(Cdk1p); required for G1/S and G2/M phase transitions and budding; mediates the phosphorylation and degradation of Sic1p; modulates proteolysis of M-phase targets through interactions with the proteasome; role in transcriptional regulation, recruiting proteasomal subunits to target gene promoters (1, 2, 3, 4, 5, 6 and see Summary Paragraph)
Name Description Cdc28 Kinase Subunit 1
Chromosomal Location
ChrII:504854 to 505306 | ORF Map | GBrowse
Genetic position: 73 cM
Gene Ontology Annotations All CKS1 GO evidence and references
  View Computational GO annotations for CKS1
Molecular Function
Manually curated
Biological Process
Manually curated
Cellular Component
Manually curated
Regulators 8 genes
Classical genetics
Large-scale survey
reduction of function
269 total interaction(s) for 180 unique genes/features.
Physical Interactions
  • Affinity Capture-MS: 57
  • Affinity Capture-RNA: 2
  • Affinity Capture-Western: 25
  • Biochemical Activity: 2
  • Co-crystal Structure: 1
  • Co-localization: 1
  • Co-purification: 1
  • PCA: 3
  • Reconstituted Complex: 7
  • Two-hybrid: 10

Genetic Interactions
  • Dosage Growth Defect: 4
  • Dosage Lethality: 1
  • Dosage Rescue: 3
  • Negative Genetic: 118
  • Positive Genetic: 21
  • Synthetic Growth Defect: 5
  • Synthetic Lethality: 6
  • Synthetic Rescue: 2

Expression Summary
Length (a.a.) 150
Molecular Weight (Da) 17,795
Isoelectric Point (pI) 6.42
Phosphorylation PhosphoGRID | PhosphoPep Database
sequence information
ChrII:504854 to 505306 | ORF Map | GBrowse
Genetic position: 73 cM
Last Update Coordinates: 2011-02-03 | Sequence: 1997-01-28
Subfeature details
Most Recent Updates
Coordinates Sequence
CDS 1..453 504854..505306 2011-02-03 1997-01-28
Retrieve sequences
Analyze Sequence
S288C only
S288C vs. other species
S288C vs. other strains
External Links All Associated Seq | Entrez Gene | Entrez RefSeq Protein | MIPS | Search all NCBI (Entrez) | UniProtKB
Primary SGDIDS000000339

Cks1p is a protein that associates with Cdc28p and is involved in cell cycle control. Classic genetic screens in yeast identified many of the genes involved in the cell cycle (7, 8). One such gene, CDC28, was shown to be a highly conserved cyclin-dependent kinase (CDK) that plays a critical role in progression through the cell cycle (9, 10, 11). The CDKs are only catalytically active when associated with a cyclin (12). In addition to the cyclins, several other positive and negative regulators of CDKs have been identified. One such regulator is Cks1p, a small protein that physically associates with the active (ie. cyclin bound) form of Cdc28p and acts as its phosphoadaptor subunit (1, 6). CKS1 was originally isolated as a high-copy suppressor of cdc28 mutations (1). Null mutations in CKS1 are lethal, and temperature-sensitive cks1 alleles cause pleiotropic cell cycle defects but have no effects on Cdc28/cyclin complex formation or activity. Thus, it was proposed that Cks1p may perform a more subtle role in regulation of Cdc28p, such as targeting the Cdc28/cyclin complex to its substrates (2). The crystal structure of a human CDK bound to human Cks1 showed that CDK-Cks1 binding occurs at a site adjacent to the catalytic site, which supports this model (13). It was shown that Cks1p binds Sic1p and mediates its cyclin-dependent docking to CDK, thus facilitating the multisite phosphorylation of Sic1p that directs it to SCF-mediated destruction at the onset of S phase (6).

CKS1 homologs have also been identified in pombe (suc1) and Xenopus (Xe-p9) (1, 14); the human, yeast, and Xenopus proteins share over 50% identity over a central domain (12). In addition, the human and pombe homologs can complement a cks1 null mutation in S. cerevisiae, and the human proteins bind to both human and yeast Cdc28 13.

An excellent comprehensive review about the yeast cell cycle can be found in "Molecular and Cellular Biology of the Yeast Saccharomyces" 12.

Last updated: 2013-05-17 Contact SGD

References cited on this page View Complete Literature Guide for CKS1
1) Hadwiger JA, et al.  (1989) The Saccharomyces cerevisiae CKS1 gene, a homolog of the Schizosaccharomyces pombe suc1+ gene, encodes a subunit of the Cdc28 protein kinase complex. Mol Cell Biol 9(5):2034-41
2) Tang Y and Reed SI  (1993) The Cdk-associated protein Cks1 functions both in G1 and G2 in Saccharomyces cerevisiae. Genes Dev 7(5):822-32
3) Kaiser P, et al.  (1999) Cyclin-dependent kinase and Cks/Suc1 interact with the proteasome in yeast to control proteolysis of M-phase targets. Genes Dev 13(9):1190-202
4) Reynard GJ, et al.  (2000) Cks1 is required for G(1) cyclin-cyclin-dependent kinase activity in budding yeast. Mol Cell Biol 20(16):5858-64
5) Morris MC, et al.  (2003) Cks1-dependent proteasome recruitment and activation of CDC20 transcription in budding yeast. Nature 423(6943):1009-13
6) Koivomagi M, et al.  (2011) Cascades of multisite phosphorylation control Sic1 destruction at the onset of S phase.LID - 10.1038/nature10560 [doi] Nature ()
7) Hartwell LH, et al.  (1973) Genetic Control of the Cell Division Cycle in Yeast: V. Genetic Analysis of cdc Mutants. Genetics 74(2):267-286
8) Reed SI  (1980) The selection of S. cerevisiae mutants defective in the start event of cell division. Genetics 95(3):561-77
9) Reed SI, et al.  (1985) Protein kinase activity associated with the product of the yeast cell division cycle gene CDC28. Proc Natl Acad Sci U S A 82(12):4055-9
10) Reed SI  (1992) The role of p34 kinases in the G1 to S-phase transition. Annu Rev Cell Biol 8():529-61
11) Nasmyth K  (1993) Control of the yeast cell cycle by the Cdc28 protein kinase. Curr Opin Cell Biol 5(2):166-79
12) Lew DJ, et al.  (1997) "Cell cycle control in Saccharomyces cerevisiae." Pp. 607-695 in The Molecular and Cellular Biology of the Yeast Saccharomyces: Cell Cycle and Cell Biology, edited by Pringle JR, Broach JR and Jones EW. Cold Spring Harbor, NY: Cold Spring Harbor Laboratory Press
13) Richardson HE, et al.  (1990) Human cDNAs encoding homologs of the small p34Cdc28/Cdc2-associated protein of Saccharomyces cerevisiae and Schizosaccharomyces pombe. Genes Dev 4(8):1332-44
14) Patra D and Dunphy WG  (1996) Xe-p9, a Xenopus Suc1/Cks homolog, has multiple essential roles in cell cycle control. Genes Dev 10(12):1503-15