MAPKAP kinase-2 is a cell cycle checkpoint kinase that regulates the G2/M transition and S phase progression in response to UV irradiation.
The cellular response to DNA damage is mediated by evolutionarily conserved Ser/Thr kinases, phosphorylation of Cdc25 protein phosphatases, binding to 14-3-3 proteins, and exit from the cell cycle. To investigate DNA damage responses mediated by the p38/stress-activated protein kinase (SAPK) axis of signaling, the optimal phosphorylation motifs of mammalian p38alpha SAPK and MAPKAP kinase-2 were determined. The optimal substrate motif for MAPKAP kinase-2, but not for p38 SAPK, closely matches the 14-3-3 binding site on Cdc25B/C. We show that MAPKAP kinase-2 is directly responsible for Cdc25B/C phosphorylation and 14-3-3 binding in vitro and in response to UV-induced DNA damage within mammalian cells. Downregulation of MAPKAP kinase-2 eliminates DNA damage-induced G2/M, G1, and intra S phase checkpoints. We propose that MAPKAP kinase-2 is a new member of the DNA damage checkpoint kinase family that functions in parallel with Chk1 and Chk2 to integrate DNA damage signaling responses and cell cycle arrest in mammalian cells.
Pubmed ID: 15629715 RIS Download
14-3-3 Proteins | Amino Acid Motifs | Amino Acid Sequence | Apoptosis | Base Sequence | Catalytic Domain | Cell Cycle | Cell Cycle Proteins | Cell Line | DNA Damage | Humans | In Vitro Techniques | Intracellular Signaling Peptides and Proteins | Models, Biological | Models, Molecular | Phosphorylation | Protein Kinases | Protein-Serine-Threonine Kinases | RNA, Small Interfering | Recombinant Fusion Proteins | Static Electricity | Ultraviolet Rays | cdc25 Phosphatases | p38 Mitogen-Activated Protein Kinases