The CKS1B protein binds to the catalytic subunit of the cyclin-dependent kinases and is essential for their biological function. The CKS1B mRNA is found to be expressed in different patterns through the cell cycle in HeLa cells, which reflects a specialized role for the encoded protein.[6]
CKS1B and CKS2 proteins have demonstrated principal roles in cell cycle regulation. Defined originally as suppressors of mutations in both fission and budding yeast Cdk1 genes, Cks molecules interact with Cdk1, Cdk2 and Cdk3. These Cdk-dependent enzyme complexes in cell cycle regulation frequently consist of Cdk molecules bound to a catalytic Cdk subunit, i.e. Cks and a regulatory cyclin subunit, such as a G1 cyclin, controlling Cdk function by directing cyclin-cdk complex activity toward specific and significant substrates. Malfunctions of cdk-dependent associations lead to defects into the entry of mitosis for cells.[7]
Cks1 in the Cdk-independent pathway involves the recognition of substrates p27Kip1 and p21cip1 by directly associating with E3 SCFSkp2 when stimulated by certain mitogenic signals, such as TGF-β.[8]
Cks1-depleted breast cancer cells not only exhibit slowed G(1) progression, but also accumulate in G(2)-M due to blocked mitotic entry. Cdk1 expression, which is crucial for M phase entry, is drastically diminished by Cks1 depletion, and that restoration of cdk1 reduces G(2)-M accumulation in Cks1-depleted cells.[9]
^Ganoth D, Bornstein G, Ko TK, Larsen B, Tyers M, Pagano M, Hershko A (March 2001). "The cell-cycle regulatory protein Cks1 is required for SCF(Skp2)-mediated ubiquitinylation of p27". Nat. Cell Biol. 3 (3): 321–4. doi:10.1038/35060126. PMID11231585. S2CID9638655.
Arvai AS, Bourne Y, Hickey MJ, Tainer JA (1995). "Crystal structure of the human cell cycle protein CksHs1: single domain fold with similarity to kinase N-lobe domain". J. Mol. Biol. 249 (5): 835–42. doi:10.1006/jmbi.1995.0341. PMID7791211.
Demetrick DJ, Zhang H, Beach DH (1996). "Chromosomal mapping of the human genes CKS1 to 8q21 and CKS2 to 9q22". Cytogenet. Cell Genet. 73 (3): 250–4. doi:10.1159/000134349. PMID8697818.
Ganoth D, Bornstein G, Ko TK, et al. (2001). "The cell-cycle regulatory protein Cks1 is required for SCF(Skp2)-mediated ubiquitinylation of p27". Nat. Cell Biol. 3 (3): 321–4. doi:10.1038/35060126. PMID11231585. S2CID9638655.
Seeliger MA, Breward SE, Itzhaki LS (2003). "Weak cooperativity in the core causes a switch in folding mechanism between two proteins of the cks family". J. Mol. Biol. 325 (1): 189–99. doi:10.1016/S0022-2836(02)01202-0. PMID12473461.
Shaughnessy J (2006). "Amplification and overexpression of CKS1B at chromosome band 1q21 is associated with reduced levels of p27Kip1 and an aggressive clinical course in multiple myeloma". Hematology. 10 Suppl 1 (4): 117–26. doi:10.1080/10245330512331390140. PMID16188652. S2CID16583295.
Yao ZP, Zhou M, Kelly SE, et al. (2006). "Activation of ubiquitin ligase SCF(Skp2) by Cks1: insights from hydrogen exchange mass spectrometry". J. Mol. Biol. 363 (3): 673–86. doi:10.1016/j.jmb.2006.08.032. PMID16979657.
