Anti-phospho-Chk2 (Thr68) (Checkpoint Kinase 2, Rad 53)

Chk2 is the mammalian homologue of the budding yeast Rad53 and fission yeast Cds1 checkpoint kinases (1-3). The amino-terminal domain of Chk2 contains a series of seven serine or threonine residues (Ser19, Thr26, Ser28, Ser33, Ser35, Ser50 and Thr68) followed by glutamine (SQ or TQ motif). These are known to be preferred sites for phosphorylation by ATM/ATR kinases (4). Indeed, after DNA damage by ionizing radiation (IR), UV irradiation and DNA replication blocked by hydroxyurea, Thr68 and other sites in this region become phosphorylated by ATM/ATR (5-7). The SQ/TQ cluster domain, therefore, seems to have a regulatory function. The p53 tumor-suppressor gene integrates numerous signals that control cell life and death. Several novel molecules involved in p53 signaling, including CHK2, p53R2, p53AIP1, Noxa, PIDD, and PID/MTA2, were recently discovered. The checkpoint kinase CHK2 is the mammalian homologue of yeast Cds1/Rad53. In response to DNA damage, the checkpoint kinase ATM phosphorylates and activates CHK2, which in turn directly phosphorylates and activates p53. CHK2 serves as ATM downstream effector to mediate activation of p53. CHK2 also phosphorylates and activates BRCA1, the product of a tumor suppressor gene that is mutated in breast and ovarian cancer. Applications: Suitable for use in Western Blot, Immunocytochemistry, Immunofluorescence, Immunoprecipitation and Flow Cytometry. Other applications not tested. Recommended Dilutions: Western Blot: 1:1000, Immunofluorescence (IC): 1:100, Immunoprecipitation: 1:100, Flow Cytometry: 1:800, Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4°C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20°C. Aliquots are stable for 12 months after receipt. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.