Phospho-CHEK2 (Ser516) Antibody

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Description

Definition and Target Specificity of Phospho-CHEK2 (Ser516) Antibody

The Phospho-CHEK2 (Ser516) Antibody is a polyclonal antibody designed to detect endogenous levels of Checkpoint Kinase 2 (CHEK2) protein only when phosphorylated at serine residue 516 (Ser516). This phosphorylation event occurs in response to DNA damage and replication stress, playing a critical role in CHEK2’s activation and downstream signaling .

Key characteristics:

  • Immunogen: Synthetic peptide derived from human CHEK2 (amino acids 486–535) containing phosphorylated Ser516 .

  • Reactivity: Human, mouse, rat (varies by product) .

  • Applications: Western blot (WB), immunohistochemistry (IHC), immunofluorescence (IF), and ELISA .

Biological Significance of CHEK2 Phosphorylation at Ser516

CHEK2 is a serine/threonine kinase central to DNA damage checkpoint control. Phosphorylation at Ser516 regulates its activity and interactions:

Functional ImpactMechanismReference
Ubiquitination regulationPhosphorylation at Ser516 promotes CUL1-mediated ubiquitination, influencing protein stability .
Apoptosis modulationEnhances CHEK2’s pro-apoptotic role by stabilizing p53/TP53 and activating E2F1 transcription .
Autophosphorylation feedbackPart of a broader activation loop involving Thr383/Thr387 autophosphorylation .

DNA Damage Response Studies

  • The antibody has been used to map CHEK2 activation in UVB-irradiated cells, showing caffeine-dependent suppression of ATR/Chk1 pathways .

  • Identifies CHEK2’s role in stabilizing RAD51 chromatin association during homologous recombination repair .

Cancer Research

  • Mutations in CHEK2 (e.g., Li-Fraumeni syndrome) correlate with breast cancer, sarcomas, and prostate cancer. The antibody aids in assessing CHEK2 phosphorylation status in tumor samples .

  • Phospho-Ser516 CHEK2 levels are inversely correlated with MDM2-mediated p53 degradation, influencing chemotherapy responses .

Validation and Quality Control

  • Specificity: ≤1% cross-reactivity with non-phosphorylated CHEK2 peptides .

  • Buffer Composition: PBS with 50% glycerol and 0.02% sodium azide (common across vendors) .

  • Batch Consistency: Validated using siRNA-mediated CHEK2 knockdown and phosphopeptide competition assays .

Clinical and Therapeutic Implications

Phospho-CHEK2 (Ser516) detection is critical for:

  1. Prognostic Biomarker Development: Correlates with chemosensitivity in BRCA1/2-deficient cancers .

  2. Drug Discovery: Screens for inhibitors targeting CHEK2’s kinase activity (e.g., in combination with PARP inhibitors) .

Product Specs

Form
Supplied at 1.0mg/mL in phosphate buffered saline (without Mg2+ and Ca2+), pH 7.4, 150mM NaCl, 0.02% sodium azide and 50% glycerol.
Lead Time
Typically, we can ship products within 1-3 business days after receiving your order. Delivery time may vary depending on the shipping method or location. For specific delivery times, please consult your local distributors.
Synonyms
CDS 1 antibody; Cds1 antibody; Cds1 homolog antibody; Checkpoint kinase 2 antibody; Checkpoint like protein CHK2 antibody; CHEK 2 antibody; Chek2 antibody; Chk 2 antibody; CHK2 checkpoint homolog (S. pombe) antibody; CHK2 checkpoint homolog antibody; CHK2_HUMAN antibody; hCds1 antibody; HuCds 1 antibody; LFS 2 antibody; LFS2 antibody; PP1425 antibody; RAD 53 antibody; RAD53 antibody; Rad53 homolog antibody; Serine/threonine protein kinase Chk2 antibody; Serine/threonine-protein kinase Chk2 antibody
Target Names
Uniprot No.

Target Background

Function
Checkpoint kinase 2 (CHEK2), a serine/threonine-protein kinase, plays a critical role in cell cycle regulation, DNA repair, and apoptosis in response to DNA double-strand breaks. It also contributes to cell cycle control during unperturbed cell cycles. Upon activation, CHEK2 phosphorylates various effector proteins, preferentially targeting the consensus sequence [L-X-R-X-X-S/T].

CHEK2 regulates cell cycle checkpoint arrest by phosphorylating CDC25A, CDC25B, and CDC25C, inhibiting their phosphatase activity. This inhibition leads to increased tyrosine phosphorylation of CDK-cyclin complexes, ultimately blocking cell cycle progression. CHEK2 can also phosphorylate NEK6, a protein involved in G2/M cell cycle arrest.

In the context of DNA repair, CHEK2 phosphorylates BRCA2, enhancing the association of RAD51 with chromatin and promoting DNA repair by homologous recombination. Additionally, CHEK2 stimulates the transcription of genes involved in DNA repair (including BRCA2) by phosphorylating and activating the transcription factor FOXM1.

CHEK2 regulates apoptosis through phosphorylation of p53/TP53, MDM4, and PML. Phosphorylation of p53/TP53 at 'Ser-20' by CHEK2 can alleviate inhibition by MDM2, leading to accumulation of active p53/TP53. Phosphorylation of MDM4 can also reduce p53/TP53 degradation. Moreover, CHEK2 controls the transcription of pro-apoptotic genes by phosphorylating the transcription factor E2F1.

As a tumor suppressor, CHEK2 may also have a DNA damage-independent function in mitotic spindle assembly through phosphorylation of BRCA1. Its absence can contribute to the chromosomal instability observed in some cancer cells. CHEK2 promotes the association of CCAR2 and SIRT1 and is required for CCAR2-mediated SIRT1 inhibition.
Gene References Into Functions
  1. This study aimed to molecularly define and determine the contribution of two rare, apparently novel CHEK2 Large Genomic Rearrangements, among Greek breast cancer patients. PMID: 29785007
  2. The CHEK2 Y390C mutation induced drug resistance of triple-negative breast cancer cells to chemotherapeutic drugs. PMID: 29761796
  3. CHEK2 Germ Line Mutation is not associated with Familial and Sporadic Breast Cancer. PMID: 29479983
  4. Chk1 and Chk2 are significantly expressed in human sperm. In cases of sperm DNA damage, upregulated Chk1 expression may enhance sperm apoptosis leading to asthenospermia, while increased Chk2 expression may inhibit spermatogenesis, resulting in oligospermia. PMID: 29658237
  5. CHK1 and CHK2, along with their activated forms, are frequently expressed in HGSC effusions, with higher expression following chemotherapy exposure. Their expression is related to survival. PMID: 29804637
  6. This is the first article to report that an identical germline mutation of the CHEK2 gene, p.R180C, exists in both NF1 and NF2 patients. PMID: 29879026
  7. Results suggested that there was a correlation between mutation of the CHEK2 gene and gastric cancer. PMID: 29067458
  8. Truncating variants in PALB2, ATM and CHEK2, but not XRCC2, were associated with increased breast cancer risk. PMID: 28779002
  9. Our results identify a novel link between XRRA1 and the ATM/CHK1/2 pathway and suggest that XRRA1 is involved in a DNA damage response that drives radio- and chemoresistance by regulating the ATM/CHK1/2 pathway. PMID: 29082250
  10. BRCA2 and CHEK2 play an important role in the genetic susceptibility to urinary tract cancers. PMID: 27632928
  11. Checkpoint kinase 2 (Chk2) inhibition suppressed C-terminal acetylation of p53 and delayed the induction of p53-target genes under heat stress (HS). Chk2 inhibition failed to inhibit apoptosis induced by HS, indicating that Chk2 was dispensable for p53-dependent apoptosis under HS. Chk2 inhibition abrogated G2/M arrest and promoted cell death induced by HS in cells with p53 defects. PMID: 28733865
  12. The inhibition of CHK2 expression reduced detachment-induced apoptosis but did not influence the ability of cells to migrate and invade. This suggests that CHK2 could inhibit tumor progression and metastatic potential by enhancing anoikis. PMID: 29486482
  13. These data suggest that the CHEK2 c.1100delC mutation is associated with an increased risk for MBC in the Finnish population. PMID: 28874143
  14. Data suggest that mediator complex subunit 1 (Med1/TRAP220) is a target for checkpoint kinase 2 (Chk2)-mediated phosphorylation and may play a role in cellular DNA damage responses by mediating proper induction of gene transcription upon DNA damage. PMID: 28430840
  15. This report proposes a novel strategy of Twist1 suppression through Chk2 induction, which prevents metastatic dissemination and promotes premature senescence in p53-defective invasive cancer cells. PMID: 28498365
  16. This study provides evidence that hepatocarcinogenesis with lagging chromosomes elicits the expression of DNA damage response protein Chk2. Thus, the overexpression of Chk2 and its mislocalisation within structures of the mitotic spindle contribute to sustained cell division and chromosome missegregation. PMID: 28360097
  17. PI3K kinase activity is necessary for maintaining 4E-BP1 stability. Our results also suggest a novel biological role for 4E-BP1 in regulating cell cycle G2 checkpoint in response to IR stress, in association with controlling CHK2 phosphorylation. PMID: 28539821
  18. Data show that the checkpoint kinase 1/2 (Chk1/Chk2) inhibitor prexasertib (LY2606368) inhibits cell viability in B-/T-ALL cell lines. PMID: 27438145
  19. Results confirm the predicted multiplicative relationship between CHEK2*1100delC and the common low-penetrance susceptibility variants for breast cancer. PMID: 27711073
  20. Results show that Chk2 expression is regulated by 14-3-3s in G2-M arrest for non-homologous end joining repair, likely via PARP1. PMID: 28087741
  21. Results indicate that CHEK2 possesses non-cell-autonomous tumor suppressor functions, and present the Chk2 protein as an important mediator in the functional interplay between breast carcinomas and their stromal fibroblasts through repressing the expression/secretion of SDF-1 and IL-6. PMID: 27484185
  22. Variants in CHEK2 were associated with moderate risks of breast cancer. PMID: 28418444
  23. In this paper, we describe an extension to the BOADICEA model to incorporate the effects of intermediate risk variants for breast cancer, specifically loss of function mutations in the three genes for which the evidence for association is clearest and the risk estimates most precise: PALB2, CHEK2 and ATM. PMID: 27464310
  24. SIAH2 regulates CHK2 basal turnover, with important consequences on cell-cycle control and on the ability of hypoxia to alter the DNA damage-response pathway in cancer cells. PMID: 26751770
  25. CHECK2 rare variants were associated with an increased risk of breast cancer and prostate cancer. PMID: 27595995
  26. The MCM2-MCM6 complex is required for CHK2 chromatin loading and its phosphorylation to DNA damage response in squamous cell carcinoma cells. PMID: 27964702
  27. Based on analyses of approximately 87,000 controls and patients with breast cancer from population- and hospital-based studies, our best estimate for the relative risk of invasive breast cancer for carriers of the 1100delC mutation in CHEK2, compared with noncarriers, was 2.26 (95% CI, 1.90 to 2.69). PMID: 27269948
  28. The G2 damage checkpoint prevents stable recruitment of the chromosome-packaging-machinery components condensin complex I and II onto the chromatin even in the presence of an active Cdk1. PMID: 27792460
  29. Data suggest that cancer risks reported for founder mutations may be generalizable to all CHEK2 + s, particularly for breast cancer. PMID: 27751358
  30. The K373E mutation of CHK2 in tumorigenesis. PMID: 27716909
  31. Checkpoint kinase 1 and 2 signaling is important for apoptin regulation. PMID: 27512067
  32. High CHEK2 expression is associated with Lung Adenocarcinoma. PMID: 28373435
  33. High expression of pCHK2-Thr68 was associated with decreased patient survival (p = 0.001), but was not an independent prognostic factor. Our results suggest that pCHK2-Thr68 and pCDC25C-Ser216 play important roles in breast cancer and may be potential treatment targets. PMID: 27801830
  34. Our study reports the first case of Li-Fraumeni syndrome-like in Chinese patients and demonstrates the important contribution of de novo mutations in this type of rare disease. PMID: 27442652
  35. These findings confirmed that 53BP1 loss might be a negative factor for chemotherapy efficacy, promoting cell proliferation and inhibiting apoptosis by suppressing ATM-CHK2-P53 signaling, and ultimately inducing 5-FU resistance. PMID: 27838786
  36. All 14 exons of CHEK2 were amplified and sequenced. PMID: 27510020
  37. All 14 exons of CHEK2 were amplified. PMID: 27039729
  38. CHEK2 mutation is associated with Pancreatic Cancer. PMID: 26483394
  39. Data suggest that nitroxoline induces anticancer activity through AMP-activated kinase (AMPK)/mTOR serine-threonine kinase (mTOR) signaling pathway via checkpoint kinase 2 (Chk2) activation. PMID: 26447757
  40. CHEK2 mutation carriers were characterized by older age, a history of gastric cancer in the family, locally advanced disease, lower histologic grade and luminal B type breast cancer. PMID: 26991782
  41. The germline mutations of the CHEK2 gene are associated with an increased risk of polycythaemia vera. PMID: 26084796
  42. Loss of CHK2 or PP6C-SAPS3 promotes Aurora-A activity associated with BRCA1 in mitosis. PMID: 26831064
  43. We observed a great degree of heterogeneity amongst the CHEK2*1100delC breast cancers, comparable to the BRCAX breast cancers. Copy number aberrations were mostly seen at low frequencies in both the CHEK2*1100delC and BRCAX group of breast cancers. PMID: 26553136
  44. The aim of this study was to determine the frequency and spectrum of germline mutations in BRCA1, BRCA2 and PALB2, and to evaluate the presence of the CHEK2 c.1100delC allele in these patients. PMID: 26577449
  45. Germ-line CHEK2 mutations affecting protein coding sequence confer a moderately increased risk of NHL, they are associated with an unfavorable NHL prognosis, and they may represent a valuable predictive biomarker for patients with DLBCL. PMID: 26506619
  46. Mutations in CHEK2 were most frequent in patients with hereditary non-triple-negative breast cancers. PMID: 26083025
  47. Authors propose that CHK2 is a negative regulator of androgen sensitivity and prostate cancer growth, and that CHK2 signaling is lost during prostate cancer progression to castration resistance. PMID: 26573794
  48. These data provide a rationale for further evaluation of the combination of Wee1 and Chk1/2 inhibitors in malignant melanoma. PMID: 26054341
  49. Variants at the CHEK2 locus are associated with risk of invasive epithelial ovarian cancer. [meta-analysis] PMID: 26424751
  50. CHEK2 H371Y mutation carriers are more likely to respond to neoadjuvant chemotherapy than are non-carriers. PMID: 25884806

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Database Links

HGNC: 16627

OMIM: 114480

KEGG: hsa:11200

UniGene: Hs.291363

Involvement In Disease
Li-Fraumeni syndrome 2 (LFS2); Prostate cancer (PC); Osteogenic sarcoma (OSRC); Breast cancer (BC)
Protein Families
Protein kinase superfamily, CAMK Ser/Thr protein kinase family, CHK2 subfamily
Subcellular Location
[Isoform 2]: Nucleus. Note=Isoform 10 is present throughout the cell.; [Isoform 4]: Nucleus.; [Isoform 7]: Nucleus.; [Isoform 9]: Nucleus.; [Isoform 12]: Nucleus.; Nucleus, PML body. Nucleus, nucleoplasm. Note=Recruited into PML bodies together with TP53.
Tissue Specificity
High expression is found in testis, spleen, colon and peripheral blood leukocytes. Low expression is found in other tissues.

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