Anti-phospho-Chk2 (Ser516) (Checkpoint Kinase 2, Rad 53)

Chk2 is the mammalian orthologue 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 (4,5). Indeed, after DNA damage by ionizing radiation (IR), UV irradiation or hydroxyurea treatment, 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., Phosphorylation at Thr68 is a prerequisite for the subsequent activation step, which is attributable to autophosphorylation of Chk2 on residues Thr383 and Thr387 in the activation loop of the kinase domain (8). Chk2 autophosphorylation at Ser516 is important for optimal Chk2 function, and a Ser516Ala mutant Chk2 is defective in IR-induced apoptosis (9). Applications: Suitable for use in Western Blot. Other applications not tested. Recommended Dilution: Western Blot: 1:1000, Optimal dilutions to be determined by the researcher. Storage and Stability: May be stored at 4°C for short-term only. For long-term storage and to avoid repeated freezing and thawing, aliquot. Store at -20°C. Aliquots are stable for at least 12 months at -20°C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.