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PhosphoSitePlus® Resource

  • Additional protein information
  • Analytical tools


Product Includes Quantity Applications Reactivity MW(kDa) Isotype
Phospho-Chk1 (Ser317) (D12H3) XP® Rabbit mAb 12302 20 µl
Western Blotting Immunoprecipitation Immunofluorescence
H M Mk 56 Rabbit IgG
Phospho-Chk1 (Ser345) (133D3) Rabbit mAb 2348 20 µl
Western Blotting Immunofluorescence Flow Cytometry
H M R Mk 56 Rabbit IgG
Phospho-Chk1 (Ser296) Antibody 2349 20 µl
Western Blotting
H Mk 56 Rabbit 
Chk1 (2G1D5) Mouse mAb 2360 20 µl
Western Blotting
H M R Mk 56 Mouse IgG1
Chk2 (D9C6) XP® Rabbit mAb 6334 20 µl
Western Blotting Immunoprecipitation Immunohistochemistry Immunofluorescence
H 62 Rabbit IgG
Phospho-Chk2 (Ser19) Antibody 2666 20 µl
Western Blotting Immunohistochemistry
H 62 Rabbit 
Phospho-Chk2 (Ser33/35) Antibody 2665 20 µl
Western Blotting
H Mk 62 Rabbit 
Phospho-Chk2 (Thr68) (C13C1) Rabbit mAb 2197 20 µl
Western Blotting Immunoprecipitation Immunohistochemistry Flow Cytometry
H 62 Rabbit IgG
Phospho-Chk2 (Ser516) Antibody 2669 20 µl
Western Blotting
H 62 Rabbit 
Anti-rabbit IgG, HRP-linked Antibody 7074 100 µl
Western Blotting

Product Description

The Phospho-Chk1/2 Antibody Sampler Kit offers an economical means to evaluate the phosphorylation status of Chk1 and Chk2 on multiple residues. The kit contains enough primary and secondary antibodies to perform two Western blot experiments with each primary antibody.

Specificity / Sensitivity

Each antibody in the Phospho-Chk1/2 Antibody Sampler Kit detects endogenous levels of its respective target protein.

Source / Purification

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide and are purified by protein A and peptide affinity chromatography. Monoclonal antibodies are produced by immunizing animals with recombinant human proteins or synthetic peptides.

Chk1 kinase acts downstream of ATM/ATR kinase and plays an important role in DNA damage checkpoint control, embryonic development, and tumor suppression (1). Activation of Chk1 involves phosphorylation at Ser317 and Ser345 by ATM/ATR, followed by autophosphorylation of Ser296. Activation occurs in response to blocked DNA replication and certain forms of genotoxic stress (2). While phosphorylation at Ser345 serves to localize Chk1 to the nucleus following checkpoint activation (3), phosphorylation at Ser317 along with site-specific phosphorylation of PTEN allows for re-entry into the cell cycle following stalled DNA replication (4). Chk1 exerts its checkpoint mechanism on the cell cycle, in part, by regulating the cdc25 family of phosphatases. Chk1 phosphorylation of cdc25A targets it for proteolysis and inhibits its activity through 14-3-3 binding (5). Activated Chk1 can inactivate cdc25C via phosphorylation at Ser216, blocking the activation of cdc2 and transition into mitosis (6). Centrosomal Chk1 has been shown to phosphorylate cdc25B and inhibit its activation of CDK1-cyclin B1, thereby abrogating mitotic spindle formation and chromatin condensation (7). Furthermore, Chk1 plays a role in spindle checkpoint function through regulation of aurora B and BubR1 (8). Research studies have implicated Chk1 as a drug target for cancer therapy as its inhibition leads to cell death in many cancer cell lines (9).

Chk2 is the mammalian homologue of the budding yeast Rad53 and fission yeast Cds1 checkpoint kinases (5-7). 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 (8). 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 (9-11). 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 (12).

1.  Liu, Q. et al. (2000) Genes Dev 14, 1448-59.

2.  Zhao, H. and Piwnica-Worms, H. (2001) Mol Cell Biol 21, 4129-39.

3.  Jiang, K. et al. (2003) J Biol Chem 278, 25207-17.

4.  Martin, S.A. and Ouchi, T. (2008) Mol Cancer Ther 7, 2509-16.

5.  Chen, M.S. et al. (2003) Mol Cell Biol 23, 7488-97.

6.  Zeng, Y. et al. (1998) Nature 395, 507-10.

7.  Löffler, H. et al. (2006) Cell Cycle 5, 2543-7.

8.  Zachos, G. et al. (2007) Dev Cell 12, 247-60.

9.  Garber, K. (2005) J Natl Cancer Inst 97, 1026-8.

10.  Allen, J. B. et al. (1994) Genes Dev. 8, 2401-2415.

11.  Weinert, T. A. et al. (1994) Genes Dev. 8, 652-665.

12.  Murakami, H. and Okayama, H. (1995) Nature 374, 817-819.

13.  Kastan, M.B. and Lim, D.S. (2000) Nat. Rev. Mol. Cell Biol. 1, 179-186.

14.  Matsuoka, S. et al. (2000) Proc. Natl. Acad. Sci. USA 97, 10389-10394.

15.  Melchionna, R. et al. (2000) Nat. Cell Biol. 2, 762-765.

16.  Ahn, J. Y. et al. (2000) Cancer Res. 60, 5934-5936.

Entrez-Gene Id 1111 , 11200
Swiss-Prot Acc. O14757 , O96017

For Research Use Only. Not For Use In Diagnostic Procedures.
Cell Signaling Technology is a trademark of Cell Signaling Technology, Inc.
DRAQ5 is a registered trademark of Biostatus Limited.
U.S. Patent No. 7,429,487, foreign equivalents, and child patents deriving therefrom.

Phospho-Chk1/2 Antibody Sampler Kit