BACKGROUND Checkpoint kinase 1 (Chk1) is a serine/threonine protein kinase and a key mediator in the DNA damage-induced checkpoint network.1 The key mission of Chk1 is to relay the checkpoint signals from the proximal checkpoint kinases of the phosphatidylinositol 3-kinase family, particularly ATM and ATR, and likely also the newly identified ATX, which phosphorylate and activate Chk1. The labile Chk1 protein is largely restricted to S and G2 phases. It is active even in unperturbed cell cycles, and although it is further activated in response to DNA damage or stalled replication, this may not require Chk1 dimerization or autophosphorylation.2,3 Following their activation, Chk1 phosphorylates downstream effectors that further propagate the checkpoint signaling. Depending on the type of stress, velocity of DNA damage, and cellular context, this leads to (a) switch to the stress-induced transcription program (E2F1, Brca1, p53), (b) direct or indirect initiation of DNA repair (p53), (c) acute delay (degradation of Cdc25A) and/or sustained block (Cdc25C, p53) of cell cycle progression, (d) apoptosis (p53, E2F1), and (e) modulation of the chromatin remodeling pathways (Tlk1/2).4
1. Tao, Z. F. & Lin, N. H.: Anticancer Agents Med. Chem. 6:377, 2006.
2. Lam, M. N. & Rosen, J. M.: Cell Cycle 3:1355, 2004.
3. Zhou, B. B. & Sausville, E.A.: Prog Cell Cycle Res. 5:413, 2003.
4. Bartes, J. & Lukas, J.: Cancer Cell 3:421, 2003.
Products are for research use only. They are not intended for human, animal, or diagnostic applications.
Recombinant human Chk1 protein
Mouse Monoclonal IgG1
Species & predicted
reactivity ( ):
Human, Mouse, & Rat Chk1
IHC (Paraffin) n/d
Weight of protein:
Does not cross-react with related proteins
Store at -20°C, 4°C for frequent use. Avoid repeated freeze-thaw cycles.
*Optimal working dilutions must be determined by end user.