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>   home   >   Products   >   Primary Antibodies   >   Antibody Collections   >   Phospho Antibodies   >   Chk1 Antibody Phospho (pS280)   

Chk1 Antibody Phospho (pS280)

Rabbit Monoclonal Antibody

  • WB - Chk1 Antibody Phospho (pS280) AJ1185c
    A. Western blot analysis on 293T cell lysates using anti-Phospho-Chk1 (pS280) RabMAb (Cat. #AJ1185c). Cells were either (A) untreated (B) treated with Calyculin A
Product Information
  • Applications Legend:
  • WB=Western Blot
  • IHC=Immunohistochemistry
  • IHC-P=Immunohistochemistry (Paraffin-embedded Sections)
  • IHC-F=Immunohistochemistry (Frozen Sections)
  • IF=Immunofluorescence
  • FC=Flow Cytopmetry
  • IC=Immunochemistry
  • ICC=Immunocytochemistry
  • IP=Immunoprecipitation
  • DB=Dot Blot
  • CHIP=Chromatin Immunoprecipitation
  • FA=Fluorescence Assay
  • IEM=Immunoelectronmicroscopy
  • EIA=Enzyme Immunoassay
Primary Accession O14757
Reactivity Human
Host Rabbit
Clonality Monoclonal
Clone Names EPR765
Calculated MW 54434 Da
Gene ID 1111
Other Names Serine/threonine-protein kinase Chk1, CHK1 checkpoint homolog, Cell cycle checkpoint kinase, Checkpoint kinase-1, CHEK1, CHK1
Target/Specificity A phospho-specific peptide corresponding to residues surrounding Serine 280 of human Chk1 was used as an immunogen. The antibody only detects Chk1 phosphorylated on Serine 280.
Dilution WB~~1:2500~5000
Format 50 mM Tris-Glycine (pH 7.4), 0.15 M NaCl, 40% Glycerol, 0.01% sodium azide and 0.05% BSA.
StorageMaintain refrigerated at 2-8°C for up to 6 months. For long term storage store at -20°C in small aliquots to prevent freeze-thaw cycles.
PrecautionsChk1 Antibody Phospho (pS280) is for research use only and not for use in diagnostic or therapeutic procedures.
Protein Information
Name CHEK1
Synonyms CHK1
Function Serine/threonine-protein kinase which is required for checkpoint-mediated cell cycle arrest and activation of DNA repair in response to the presence of DNA damage or unreplicated DNA. May also negatively regulate cell cycle progression during unperturbed cell cycles. This regulation is achieved by a number of mechanisms that together help to preserve the integrity of the genome. Recognizes the substrate consensus sequence [R-X-X-S/T]. Binds to and phosphorylates CDC25A, CDC25B and CDC25C. Phosphorylation of CDC25A at 'Ser-178' and 'Thr-507' and phosphorylation of CDC25C at 'Ser-216' creates binding sites for 14-3-3 proteins which inhibit CDC25A and CDC25C. Phosphorylation of CDC25A at 'Ser-76', 'Ser- 124', 'Ser-178', 'Ser-279' and 'Ser-293' promotes proteolysis of CDC25A. Phosphorylation of CDC25A at 'Ser-76' primes the protein for subsequent phosphorylation at 'Ser-79', 'Ser-82' and 'Ser-88' by NEK11, which is required for polyubiquitination and degradation of CDCD25A. Inhibition of CDC25 leads to increased inhibitory tyrosine phosphorylation of CDK-cyclin complexes and blocks cell cycle progression. Also phosphorylates NEK6. Binds to and phosphorylates RAD51 at 'Thr-309', which promotes the release of RAD51 from BRCA2 and enhances the association of RAD51 with chromatin, thereby promoting DNA repair by homologous recombination. Phosphorylates multiple sites within the C-terminus of TP53, which promotes activation of TP53 by acetylation and promotes cell cycle arrest and suppression of cellular proliferation. Also promotes repair of DNA cross-links through phosphorylation of FANCE. Binds to and phosphorylates TLK1 at 'Ser-743', which prevents the TLK1-dependent phosphorylation of the chromatin assembly factor ASF1A. This may enhance chromatin assembly both in the presence or absence of DNA damage. May also play a role in replication fork maintenance through regulation of PCNA. May regulate the transcription of genes that regulate cell- cycle progression through the phosphorylation of histones. Phosphorylates histone H3.1 (to form H3T11ph), which leads to epigenetic inhibition of a subset of genes. May also phosphorylate RB1 to promote its interaction with the E2F family of transcription factors and subsequent cell cycle arrest.
Cellular Location Nucleus. Cytoplasm. Cytoplasm, cytoskeleton, microtubule organizing center, centrosome. Note=Nuclear export is mediated at least in part by XPO1/CRM1. Also localizes to the centrosome specifically during interphase, where it may protect centrosomal CDC2 kinase from inappropriate activation by cytoplasmic CDC25B
Tissue Location Expressed ubiquitously with the most abundant expression in thymus, testis, small intestine and colon
Research Areas
Citations (0)

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Chk1 is an evolutionarily conserved protein kinase that has been implicated in cell cycle checkpoint control in lower eukaryotes. Chk1 plays an essential role in the mammalian DNA damage checkpoint, embryonic development, and tumor suppression (1). It is activated in response to replication blocks and genotoxic stress, via phosphorylation of Serine 317 and Serine 345 (2). Activated Chk1 can bind to, phosphorylate (at Serine 216) and inactivate cdc25c (3, 4). Chk1 is phosphorylated by ATR in response to ultraviolet irradiation and inhibition of DNA replication, and by ATM in response to ionizing irradiation, resulting in enhanced kinase activity. Chk1 is phosphorylated at Serine 280 by AKT1/PKB, which is thought to promote mono and/or diubiquitination (5).


1. Liu Q., et al. Genes Dev. 14:1448-1459, 2000
2. Zhao, H. et al. Mol. Cell. Biol. 21: 4129-4139, 2001
3. Zeng, Y., et al. Nature 395: 507-510, 1998
4. Sanchez, Y., et al. Science 277: 1497-501, 1997
5. The UniProt Consortium, The Universal Protein Resource (UniProt) Nucleic Acids Res. 36:D190-D195, 2008

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Cat# AJ1185c
(40 western blots)
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