Related Experiment Video
Updated: Aug 20, 2026

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay
Published on: May 3, 2018
Cyclin-dependent kinase 1 gene expression is associated with poor prognosis in gastric carcinoma
Taka-Aki Masuda1, Hiroshi Inoue, Koujiro Nishida
1Department of Molecular and Surgical Oncology, Medical Institute of Bioregulation, Kyushu University, Beppu, Japan.
Purpose:
A low expression level of cyclin-dependent kinase (Cdk) inhibitor p27 is associated with high aggressiveness and poor prognosis of various carcinomas. Human Cdk subunit 1 (Cks1), as well as S-phase kinase-associated protein 2 (Skp2), is an essential and specific factor in the p27 proteolysis by SCF(Skp2) ubiquitin ligase. The purpose of this study is to clarify the clinical significance of Cks1 expression and the relationship between Cks1 and p27 expression in gastric carcinomas.
Experimental Design:
We measured Cks1 expression using quantitative reverse transcription-PCR in 76 human gastric carcinomas and p27 expression using immunohistochemistry in 28 cases. Moreover, we established Cks1- and/or Skp2-transfected gastric carcinoma cell lines and assessed the relationship between Cks1, Skp2, and p27 expression using quantitative reverse transcription-PCR and Western blot analysis.
Results:
Cks1 high expression was correlated with poor prognosis (P < 0.05) and Cks1 expression was inversely correlated with the expression level of p27 protein in gastric carcinomas (P < 0.05). Using combined Skp2 data [T-a. Masuda, Cancer Res., 62: 3819-3825, 2002], 88.9% of the Cks1/Skp2 double-high cases expressed a low level of p27 protein and showed the poorest prognosis (P < 0.05). Western blot analysis showed that Cks1/Skp2-cotransfected cells expressed a much lower level of p27 protein than the controls.
Conclusions:
These findings indicate that Cks1, as well as Skp2, regulates the expression level of p27 protein in gastric carcinomas. Cks1 could play an important role in gastric carcinoma progression and would be a novel target for the treatment of gastric carcinomas as well as a strong prognostic marker.
Related Concept Videos
Positive Regulator Molecules
Inhibition of Cdk Activity
M-Cdk Drives Transition Into Mitosis
Cyclin-dependent kinases, or Cdks, work in concert with cyclins to control cell cycle transitions. M-Cdk, a complex of Cdk1 bound to M cyclin, is a well-known example of this coordinated control that drives the transition from the G2 to the M phase.
M cyclin...
mTOR Signaling and Cancer Progression
The mTOR pathway or the...
MAPK Signaling Cascades
Inhibition of CDK Activity

