Claspin Antibody

2800:

Western Blotting

Claspin Antibody detects endogenous levels of total claspin protein.

Polyclonal antibodies are produced by immunizing animals with a synthetic peptide corresponding to amino acids near the carboxy terminus of human claspin. Antibodies are purified by peptide affinity chromatography.

Western Blotting

Western blot analysis of extracts of HEL, SH-SY5Y and NCCIT cells using Claspin Antibody.

Originally identified in Xenopus (1), and later in human cells (2), claspin is a mediator of Chk1 signal transduction at the replication checkpoint and in response to DNA damage. Expression of claspin is cell cycle-regulated, with protein levels peaking at the S/G2 phase (2). Expression is negatively regulated by both proteosome- and caspase-mediated degradation (3), and stabilized by activation of Chk1 (4). Claspin is a chromatin-bound protein, and has been shown to interact with the PNCA complex in the absence of DNA damage (5). Following checkpoint activation it remains chromatin-bound but is released from the PCNA complex and is phosphorylated in an ATR-dependent manner. Phosphorylated claspin interacts with several components of the DNA damage response including BRCA1 (6) and Chk1 (7), leading to ATR-dependent phosphorylation on each of these proteins. Phosphorylated Rad17 has also been shown to bind to and regulate the phosphorylation of claspin (8). It has been proposed that claspin behaves as a tumor suppressor in come cases since down-regulation promotes apoptosis following genotoxic stress (2). Conversely, claspin seems to behave as an oncogene in other instances since overexpression promotes cellular proliferation (6). Upregulated claspin has been suggested to be a sensitive marker of abnormally proliferating cells (9).

1. Kumagai, A. and Dunphy, W.G. (2000) Mol Cell 6, 839-49.
2. Chini, C.C. and Chen, J. (2003) J Biol Chem 278, 30057-62.
3. Semple, J.I. et al. (2007) Cell Death Differ 14, 1433-42.
4. Chini, C.C. et al. (2006) Oncogene 25, 4165-71.
5. Brondello, J.M. et al. (2007) Biochem Biophys Res Commun 354, 1028-33.
6. Lin, S.Y. et al. (2004) Proc Natl Acad Sci U S A 101, 6484-9.
7. Jeong, S.Y. et al. (2003) J Biol Chem 278, 46782-8.
8. Wang, X. et al. (2006) Mol Cell 23, 331-41.
9. Tsimaratou, K. et al. (2007) J Pathol 211, 331-9.

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• 2360 Chk1 (2G1D5) Mouse mAb
• 2348 Phospho-Chk1 (Ser345) (133D3) Rabbit mAb
• 9010 BRCA1 Antibody
• 9009 Phospho-BRCA1 (Ser1524) Antibody
• 9494 Caspase-7 (C7) Mouse mAb (Human Specific)
• 9492 Caspase-7 Antibody
• 7071 Phototope^® -HRP Western Blot Detection System, Anti-rabbit IgG, HRP-linked Antibody
• 7074 Anti-rabbit IgG, HRP-linked Antibody
• 7720 Prestained Protein Marker, Broad Range (Premixed Format)
• 7727 Biotinylated Protein Ladder Detection Pack
• 7003 20X LumiGLO^® Reagent and 20X Peroxide

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