Rabbit Polyclonal Phospho-Chk1 (S280) antibody (STJ90221)


Reactivity: Human
Applications: WB, ELISA
Conjugation: Unconjugated
Supplier: St John’s Laboratory Ltd.

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Rabbit Polyclonal Phospho-Chk1 (S280) antibody (STJ90221)

Supplier: St John’s Laboratory Ltd.

Recommended applications: WB, ELISA

Recommended dilution: WB 1:500-1:2000; ELISA 1:20000;

Recommended protocols: check protocols

Image descriptions:

Click or hover above images to see image description for Chk1 (phospho Ser280) Polyclonal Antibody.

Alternative names:

Check alternative names for the antibody


CHEK1 antibody, CHK1 antibody,|C85740 antibody|Cell cycle checkpoint kinase antibody|Checkpoint , S. pombe, homolog of, 1 antibody|Checkpoint kinase 1 antibody|Checkpoint kinase 1 homolog (S. pombe) antibody|CHEK 1 antibody|Chek1 antibody|Chk 1 antibody|Chk1 antibody|CHK1 checkpoint homolog (S. pombe) antibody|CHK1_HUMAN antibody|EC antibody|rad27 antibody|Serine/threonine protein kinase Chk1 antibody|Serine/threonine-protein kinase CHK1 antibody|STT3, subunit of the oligosaccharyltransferase complex, homolog A (S. cerevisiae) antibody|Anti-Chk1 antibody [EP691Y] (ab40866)
SCBT cat No: sc-56288|sc-7234|sc-377231|sc-56291|sc-515369|sc-7898|sc-8408|sc-292584|sc-136251|sc-17747|sc-5278|sc-17748|



Chk1 (phospho Ser280) Polyclonal Antibody

Catalogue No.





Phospho-Chk1 (S280) Polyclonal Antibody detects endogenous levels of Chk1 protein only when phosphorylated at S280.


Synthesized phospho-peptide derived from Chk1 (phospho Ser280) at AA range 220-300





Recommended dilution

WB 1:500-1:2000; ELISA 1:20000;







Molecular weight

54/60 kDa


Chk1 (phospho Ser280) Antibody was tube-contained. Liquid in PBS containing 50% glycerol, 0.5% BSA and 0.02% sodium azide.


1 mg/ml


Chk1 (phospho Ser280) Antibody was affinity-purified from rabbit antiserum by affinity-chromatography using epitope-specific immunogen.


-20 Celsius degree. Avoid repeated freeze/thaw cycles.

Alternative antibody names

Serine/threonine-protein kinase Chk1 antibody, CHK1 checkpoint homolog antibody, Cell cycle checkpoint kinase antibody, Checkpoint kinase-1 antibody

Database links

Human UniProt/Swiss-Prot:O14757;Mouse UniPort/Swiss-Prot: O35280;Rat UniProt/Swiss-Port: Q91ZN7;Human Entrez Gene: 1111;Mouse Entrez Gene: 12649;Rat Entrez Gene: Rn.33267

Protein names

Serine/threonine-protein kinase Chk1 , CHK1 checkpoint homolog , Cell cycle checkpoint kinase , Checkpoint kinase-1

Protein 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. / Isoform 2: Endogenous repressor of isoform 1, interacts with, and antagonizes CHK1 to promote the S to G2/M phase transition. / ATP + a protein = ADP + a phosphoprotein. / Activated through phosphorylation predominantly by ATR but also by ATM in response to DNA damage or inhibition of DNA replication. Activation is modulated by several mediators including CLSPN, BRCA1 and FEM1B.

Protein tissue specificity

Expressed ubiquitously with the most abundant expression in thymus, testis, small intestine and colon.

Protein sequence and domain

The autoinhibitory region (AIR) inhibits the activity of the kinase domain. / Belongs to the protein kinase superfamily. CAMK Ser/Thr protein kinase family. NIM1 subfamily. / Contains 1 protein kinase domain.

Protein post-translational modifications

Phosphorylated by ATR in a RAD17-dependent manner in response to ultraviolet irradiation and inhibition of DNA replication. Phosphorylated by ATM in response to ionizing irradiation. ATM and ATR can both phosphorylate Ser-317 and Ser-345 and this results in enhanced kinase activity. Phosphorylation at Ser-345 induces a change in the conformation of the protein, activates the kinase activity and is a prerequisite for interaction with FBXO6 and subsequent ubiquitination at Lys-436. Phosphorylation at Ser-345 also increases binding to 14-3-3 proteins and promotes nuclear retention. Conversely, dephosphorylation at Ser-345 by PPM1D may contribute to exit from checkpoint mediated cell cycle arrest. Phosphorylation at Ser-280 by AKT1/PKB, may promote mono and/or diubiquitination. Also phosphorylated at undefined residues during mitotic arrest, resulting in decreased activity. / Ubiquitinated. Mono or diubiquitination promotes nuclear exclusion (By similarity). The activated form (phosphorylated on Ser-345) is polyubiquitinated at Lys-436 by some SCF-type E3 ubiquitin ligase complex containing FBXO6 promoting its degradation. Ubiquitination and degradation are required to terminate the checkpoint and ensure that activated CHEK1 does not accumulate as cells progress through S phase, when replication forks encounter transient impediments during normal DNA replication.

Protein cellular localization

Nucleus / Cytoplasm / Cytoplasm > cytoskeleton > microtubule organizing center > centrosome

Research area

All research areas>Cell Cycle Proteins>Chk
(View all antibody categories related to Cell Cycle Proteins)


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St John’s Laboratory Ltd.

Product type

Primary antibody


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