Cell Signaling Technology

Product Pathways - DNA Damage

Phospho-Chk1 (Ser345) (133D3) Rabbit mAb #2348

Applications Reactivity Sensitivity MW (kDa) Isotype
W IF-IC F H M R Mk Endogenous 56 Rabbit IgG

Applications Key:  W=Western Blotting  IF-IC=Immunofluorescence (Immunocytochemistry)  F=Flow Cytometry
Reactivity Key:  H=Human  M=Mouse  R=Rat  Mk=Monkey
Species cross-reactivity is determined by western blot. Species enclosed in parentheses are predicted to react based on 100% sequence homology.

Protocols

Specificity / Sensitivity

Phospho-Chk1 (Ser345) (133D3) Rabbit mAb detects endogenous levels of Chk1 only when phosphorylated at serine 345.

Source / Purification

Monoclonal antibody is produced by immunizing animals with a synthetic phosphopeptide corresponding to residues surrounding Ser345 of human Chk1.

Western Blotting

Western Blotting

Western blot analysis of extracts from HeLa, COS, NIH/3T3 and C6 cells, untreated or UV-treated, using Phospho-Chk1 (Ser345) (133D30) Rabbit mAb.

Flow Cytometry

Flow Cytometry

Flow cytometric analysis of HeLa cells, untreated (blue) and UV-treated (green), using Phospho-Chk1 (Ser345) (133D3) Rabbit mAb.

IF-IC

IF-IC

Confocal immunofluorescent analysis of C2C12 cells, untreated (left) or UV-treated (right), using Phospho-Chk1 (Ser345) (133D3) Rabbit mAb (green). Actin filaments have been labeled with DY-554 phalloidin (red).


Background

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 and 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).

  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.

Application References

Have you published research involving the use of our products? If so we'd love to hear about it. Please let us know!

Companion Products

Rabbit Monoclonals Produced Using Epitomics® Technology, U.S. Patent No. 5,675,063.

For Research Use Only. Not For Use In Diagnostic Procedures.

Products