Cell Signaling Technology

Product Pathways - DNA Damage

Phospho-Chk2 (Ser516) Antibody #2669

Applications Reactivity MW (kDa) Source
W H 62 Rabbit

Applications Key:  W=Western Blotting
Reactivity Key:  H=Human
Species enclosed in parentheses are predicted to react based on 100% sequence homology. Species cross-reactivity is determined by Western blot.

Specificity / Sensitivity

Phospho-Chk2 (Ser516) Antibody detects endogenous levels of Chk2 only when phosphorylated at serine 516. The antibody does not cross-react with Chk2 phosphorylated at other sites.

Source / Purification

Polyclonal antibodies are produced by immunizing rabbits with a synthetic phospho-peptide (KLH-coupled) corresponding to residues surrounding Ser516 of human Chk2. Antibodies are purified by protein A and peptide affinity chromatography.

Western Blotting

Western Blotting

Western blot analysis of extracts from 293 cells, untreated or UV-treated (50 mJ/cm2, 2hrs), using Phospho-Chk2 (Ser516) Antibody (upper) or Chk2 Antibody #2662 (lower).

Background

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) each followed by glutamine (SQ or TQ motif). These are known to be preferred sites for phosphorylation by ATM/ATR kinases (4,5). 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).

  1. Allen, J.B. et al. (1994) Genes Dev. 8, 2401-2415.
  2. Weinert, T.A. et al. (1994) Genes Dev. 8, 652-665.
  3. Murakami, H. and Okayama, H. (1995) Nature 374, 817-819.
  4. Kastan, M.B. and Lim, D.S. (2000) Nat. Rev. Mol. Cell Biol. 1, 179-186.
  5. Matsuoka, S. et al. (2000) Proc. Natl. Acad. Sci. USA 97, 10389-10394.
  6. Melchionna, R. et al. (2000) Nat. Cell Biol. 2, 762-765.
  7. Ahn, J.Y. et al. (2000) Cancer Res. 60, 5934-5936.
  8. Lee, C.H. and Chung, J.H. (2001) J. Biol. Chem. 276, 30537-30541.
  9. Wu, X. and Chen, J. (2003) J. Biol. Chem. 278, 36163-36168.

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