DNA damage invokes mismatch repair-dependent cyclin D1 attenuation and retinoblastoma signaling pathways to inhibit CDK2.
DNA-damage evokes cell cycle checkpoints, which function to maintain genomic integrity. The retinoblastoma tumor suppressor (RB) and mismatch repair complexes are known to contribute to the appropriate cellular response to specific types of DNA damage. However, the signaling pathways through which these proteins impact the cell cycle machinery have not been explicitly determined. RB-deficient murine embryo fibroblasts continued a high degree of DNA replication following the induction of cisplatin damage, but were inhibited for G(2)/M progression. This damage led to RB dephosphorylation/activation and subsequent RB-dependent attenuation of cyclin A and CDK2 activity. In both Rb+/+ and Rb -/- cells, cyclin D1 expression was attenuated following DNA damage. As cyclin D1 is a critical determinant of RB phosphorylation and cell cycle progression, we probed the pathway through which cyclin D1 degradation occurs in response to DNA damage. We found that attenuation of endogenous cyclin D1 is dependent on multiple mismatch repair proteins. We demonstrate that the mismatch repair-dependent attenuation of endogenous cyclin D1 is critical for attenuation of CDK2 activity and induction of cell cycle checkpoints. Together, these studies couple the activity of the retinoblastoma and mismatch repair tumor suppressor pathways through the degradation of cyclin D1 and dual attenuation of CDK2 activity.
Lan
Zhengdao
Z
Department of Cell Biology, University of Cincinnati, Cincinnati, Ohio 45267, USA.
Sever-Chroneos
Zvjezdana
Z
Strobeck
Matthew W
MW
Park
Chi-Hyun
CH
Baskaran
R
R
Edelmann
Winfried
W
Leone
Gustavo
G
Knudsen
Erik S
ES
D000818:Animals; D020137:Base Pair Mismatch; D042846:CDC2-CDC28 Kinases; D002453:Cell Cycle; D002460:Cell Line; D002945:Cisplatin / Q000494:pharmacology; D019925:Cyclin A / Q000378:metabolism; D019938:Cyclin D1 / Q000378:metabolism*; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D004249:DNA Damage; D004260:DNA Repair; D004789:Enzyme Activation; D016195:G2 Phase; D015151:Immunoblotting; D051379:Mice; D008856:Microscopy, Fluorescence; D008938:Mitosis; D010766:Phosphorylation; D011233:Precipitin Tests; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D016160:Retinoblastoma Protein / Q000378:metabolism*; D015398:Signal Transduction; D013997:Time Factors
D019925:Cyclin A; D016160:Retinoblastoma Protein; D019938:Cyclin D1; D017346:Protein Serine-Threonine Kinases; D042846:CDC2-CDC28 Kinases; C495893:Cdk2 protein, mouse; D051357:Cyclin-Dependent Kinase 2; D018844:Cyclin-Dependent Kinases; D002945:Cisplatin