Phospho-CDC25A (S178) Antibody
Description
Definition and Development of Phospho-CDC25A (S178) Antibody
Phospho-CDC25A (S178) antibody is a rabbit-derived polyclonal antibody generated against a synthetic phosphopeptide encompassing residues surrounding serine 178 of human CDC25A. This residue lies within a regulatory domain targeted by checkpoint kinases such as CHEK1 and CHEK2 during DNA damage responses . The antibody’s immunogen sequence is proprietary, but its design ensures exclusive recognition of the phosphorylated S178 epitope, avoiding cross-reactivity with unmodified CDC25A or other CDC25 family members (e.g., CDC25B/C) .
Specificity and Reactivity
Validation studies confirm that the antibody detects endogenous CDC25A only when phosphorylated at S178. For example, western blot analyses of UV-treated HeLa and HEK293T cells show a single band at ~70 kDa, slightly higher than the predicted 59 kDa, likely due to post-translational modifications . Immunohistochemistry (IHC) in human prostate cancer tissues demonstrates robust nuclear and cytoplasmic staining, aligning with CDC25A’s subcellular localization during interphase . The antibody cross-reacts with mouse and rat orthologs, facilitating translational studies .
Biological Significance of CDC25A Phosphorylation at Ser178
CDC25A is a dual-specificity phosphatase that activates cyclin-dependent kinases (CDKs) by removing inhibitory phosphorylations at tyrosine and threonine residues. Phosphorylation at S178 modulates CDC25A’s stability and function during cell cycle checkpoints:
Regulation by DNA Damage Checkpoints
Checkpoint kinases CHEK1 and CHEK2 phosphorylate CDC25A at S178 (alongside S76, S124, S279, S293, and T507) in response to DNA damage, priming it for ubiquitination and proteasomal degradation . This degradation prevents premature cell cycle progression, allowing time for repair. For instance, transforming growth factor-β (TGF-β)-induced downregulation of CDC25A stabilizes inhibitory phosphorylations on CDK4/6, leading to G1 arrest .
Role in Cell Cycle Transitions
CDC25A promotes G1/S progression by activating CDK2-cyclin E complexes, which phosphorylate retinoblastoma (Rb) protein to release E2F transcription factors. A feedforward loop exists: activated CDK2 phosphorylates CDC25A, enhancing its phosphatase activity and accelerating Rb inactivation . Conversely, at the G2/M transition, CDC25A dephosphorylates CDK1-cyclin B1, enabling mitotic entry. Phosphorylation at S178 by CHEK1 during checkpoint activation disrupts these interactions, ensuring genomic fidelity .
Western Blotting
In UV-treated cells, the antibody detects upregulated phospho-CDC25A (S178), correlating with checkpoint activation. The 70 kDa band corresponds to phosphorylated CDC25A, with higher molecular weight attributed to additional modifications .
Immunohistochemistry
In prostate cancer tissues, strong nuclear staining reflects CDC25A’s role in proliferation. Formalin-fixed, paraffin-embedded samples require heat-mediated antigen retrieval (pH 6.0 sodium citrate buffer) for optimal signal .
Functional Studies
Microinjection of CDC25A antibodies into proliferating cells induces G1 arrest, underscoring CDC25A’s necessity for G1/S transition . Conversely, overexpression accelerates S-phase entry, linking CDC25A activity to oncogenic transformation .
Feedforward Loops in Cell Cycle Control
CDC25A and cyclin E-CDK2 form a feedforward loop that amplifies CDK2 activity, enabling cells to bypass the restriction point (R-point). Phosphorylation of CDC25A by CDK2 enhances its phosphatase activity, creating a bistable switch for irreversible cell cycle commitment . Similarly, CDC25A and cyclin B-CDK1 collaborate at the G2/M transition, where CDK1 phosphorylates CDC25A to stabilize it against checkpoint-mediated degradation .
Checkpoint Kinase Crosstalk
CHK1 phosphorylates CDC25B at S230 and S563 during unperturbed cycles, preventing premature CDK1 activation at centrosomes . Although direct evidence for CHK1 targeting CDC25A S178 is limited, checkpoint activation universally coordinates CDC25A/B/C phosphorylation to block cell cycle progression .
CDC25A in Cancer
CDC25A is overexpressed in breast, prostate, and lung cancers, correlating with poor prognosis. Its phosphorylation at S178 serves as a biomarker for checkpoint activation, potentially identifying tumors reliant on DNA repair pathways . Therapeutic strategies targeting CDC25A degradation (e.g., CHK1 inhibitors) are under investigation to sensitize cancer cells to genotoxic agents .
Antibody Utility in Biomarker Discovery
The Phospho-CDC25A (S178) antibody enables quantification of checkpoint activity in clinical samples. For example, elevated phospho-CDC25A in prostate cancer suggests active DNA damage responses, which may predict resistance to radiotherapy .
Product Specs
Target Background
- Research has revealed the role of CDC25A in BRCA-mediated tumorigenesis, which may have implications in cancer treatment. PMID: 29416040
- CDC25A has been shown to negatively regulate the antiviral immune response by inhibiting TBK1 activity. PMID: 30021902
- Studies indicate that CDC25A is elevated, activated, and plays a crucial role in neuronal cell death induced by apoptotic stimuli relevant to normal development and Alzheimer's disease (AD). PMID: 28333146
- Activation of EGFR leads to c-Src-mediated phosphorylation of CDC25A at Y59, which interacts with nuclear pyruvate kinase M2 (PKM2). PMID: 27485204
- Our findings suggest the importance of LIMD1 and CDC25A in conjunction with HPV for use as diagnostic and prognostic markers of head and neck squamous cell carcinoma (HNSCC), while RBSP3 may serve as a prognostic marker only. PMID: 29672635
- Inhibition of YBX1 suppressed lung cancer growth partly via the CDC25a pathway, and high expression of YBX1/CDC25a predicts poor prognosis in human lung adenocarcinoma. PMID: 27384875
- MCPH1 interacts with and promotes the E3 ligase betaTrCP2 to degrade CDC25A independent of DNA damage. Overexpression of betaTrCP2 or knockdown of CDC25A rectifies the high mitotic index and rescues the premature differentiation of Mcph1-deficient neuroprogenitors in vivo. MCPH1 itself is degraded by APC/CCdh1, but not APC/CCdc20, in late mitosis and G1 phase. PMID: 29150431
- The cytoplasmic relocalization of CDC25A in skin cancers results in the acquisition of an antiapoptotic function for CDC25A. PMID: 28951130
- NPAS2 plays a crucial role in HCC cell survival and tumor growth, primarily mediated by transcriptional upregulation of CDC25A. PMID: 28333141
- Research has identified cyclinD-CDK4/6 complexes as novel regulators of CDC25A stability during G1 phase, creating a negative feedback loop that controls the G1/S transition. PMID: 28192398
- These findings identify a new positive regulatory loop between CDC25A and its CDK-cyclin substrates, which contributes to accelerating entry into mitosis through the regulation of CDC25A activity in G2. PMID: 27580187
- The expression level of CDC25A was significantly increased (<0.05) after treatment with miR-675 mimics. PMID: 27644634
- miR-497 modulates the growth of chondrosarcoma cells by targeting CDC25A. PMID: 27053344
- This study demonstrated that the cell cycle pathway and the cdc25a gene may be crucial in the pathogenesis and progression of hepatocellular carcinoma. PMID: 26647881
- Increased CDC25A is associated with invasiveness in Non-small Cell Lung Cancer. PMID: 25990966
- Data indicate that nine compounds were identified with Ki values for CDC25A, -B and -C ranging from 0.01 to 4.4 muM. PMID: 26474275
- CDC25A has been identified as an early cell cycle transducer of FLT3-ITD oncogenic signaling, and as a promising target to inhibit proliferation and re-induce differentiation of FLT3-ITD acute myeloid leukemia cells. PMID: 26515730
- STK38-mediated phosphorylation of CDC25A at Ser-76 and the subsequent degradation of CDC25A are required to promote DNA damage-induced G2/M checkpoint activation. PMID: 25936524
- let-7c suppresses HCC progression, possibly by directly targeting the cell cycle regulator CDC25A and indirectly affecting its downstream target molecules. Let-7c may therefore be an effective therapeutic target for HCC. PMID: 25909324
- Results suggest that miR-449a may act as a tumor suppressor by targeting CDC25A in endometrial cancer. PMID: 24993091
- CDC25C appears to be important for the phenotype of AML cells, at least for a subset of patients. Many of the identified CDC25 inhibitors show cross-reactivity among the three CDC25 isoforms. PMID: 25397735
- Our findings suggest that expression of CDC25B may be used as a potential prognostic marker in the pathogenesis of retinoblastoma. PMID: 25326518
- These findings suggest that Cdc25a promotes human cytomegalovirus replication, and elevation of Cdc25a levels after human cytomegalovirus infection are due in part to human cytomegalovirus-mediated repression of miR-21. PMID: 25378484
- miR-424(322)/503-dependent posttranscriptional downregulation of CDC25A cooperates with transcriptional repression of the CDC25A promoter and proteasome-mediated degradation to reduce the levels of CDC25A expression and to induce cell cycle arrest. PMID: 25266660
- Findings suggest that inhibition of H19 long non-coding RNA (LncRNAH19) and miR-675 expression can promote migration and invasion of hepatocellular carcinoma (HCC) cells via AKT/GSK-3beta/Cdc25A signaling pathway. PMID: 24939300
- Accelerated cholangiocyte cystogenesis is likely due to overexpression of CDC25A. PMID: 24211536
- CDC 25A dephosphorylates NFAT, resulting in translocation to the nucleus, and NFAT in cooperation with Smad2 promotes tumor progression. PMID: 24269534
- RSK promotes G2/M transition in mammalian cells through activating phosphorylation of CDC25A and CDC25B. PMID: 23708659
- Overexpression of CDC25A was associated with a decrease in overall survival rates and disease-free survival in breast cancer patients. CDC25a is a target of HER2 signaling in human breast cancer. PMID: 23730206
- Overexpression of EGFR in head and neck squamous cell carcinoma is associated with inactivation of SH3GL2 and CDC25A genes. PMID: 23675485
- Data indicate that protein phosphatase inhibitor RE142 binds to one of the residues Cys384-Tyr386 of CDC25A, within a pocket adjacent to the catalytic site. PMID: 23467652
- Our work provides novel insight into the underlying mechanisms by which FOXM1 controls the cell cycle through its association with CDC25A. PMID: 23240008
- Destabilization of CDC25A through inhibition of Hsp90 was boosted by the phosphorylation of Ser177, which tags CDC25A to proteasomal degradation, adding to the cell-cycle inhibitory effect. PMID: 22843495
- A new role for Rock2 in modulation of CDC25A ubiquitination has been revealed, indicating a novel mechanism of CDC25A regulation and a potential function for Rock2 in the development of hepatocellular carcinoma. PMID: 22705122
- Widdrol breaks DNA directly in HT29 cells, resulting in checkpoint activation via the Chk2-p53-Cdc25A-p21-MCM4 pathway, leading to G1-phase cell cycle arrest and apoptosis. PMID: 22160829
- CDC25A plays an important physiological role in NF-kappaB activity regulation and may be an important survival mechanism of cancer cells. PMID: 22417828
- CDC25A deregulation may be involved in hematopoietic cells expansion in JAK2(V617F) patients, making this protein an attractive potential therapeutic target. PMID: 22065597
- CDC25A enhances Foxo1 stability by dephosphorylating Cdk2, and Foxo1 has been shown to directly regulate transcription of the metastatic factor MMP1. PMID: 21670150
- High-frequency canonical Wnt activation in multiple sarcoma subtypes drives proliferation through a TCF/beta-catenin target gene, CDC25A. PMID: 21575861
- Cdc14A phosphatase prevents premature activation of Cdk1 by regulating CDC25A and CDC25B at the entry into mitosis. PMID: 20956543
- This study demonstrates that the expression levels of CDC25s in human gliomas, and found that CDC25A is overexpressed, and significantly correlate with Ki-67 expression. PMID: 20217459
- Results reveal an unexpected role of CDC25A down-regulation and the inhibitory phosphorylation of cdk2 T14 and Y15 in cell cycle quiescence during muscle differentiation, and implicate miRNAs-322 and -503 in the process. PMID: 20462953
- 263C/T and -51C/G polymorphisms of the CDC25A gene could be candidate markers for earlier diagnosis and targets for breast cancer therapy. PMID: 20614206
- Results suggest that TRB3 is a regulator for adjusting the expression level of CDC25A both in normal and genotoxic conditions. PMID: 20606298
- 14-3-3 protein gamma mediates the interaction between Checkpoint kinase 1 and CDC25A. PMID: 20639859
- Casein kinase 1 functions as both penultimate and ultimate kinase in regulating CDC25A destruction. PMID: 20348946
- NEK11 controls degradation of CDC25A by directly phosphorylating CDC25A on residues whose phosphorylation is required for beta-TrCP mediated CDC25A polyubiquitylation and degradation. PMID: 20090422
- As a major regulator of CDC25A, Dub3 is an example of a transforming ubiquitin hydrolase that subverts a key component of the cell cycle machinery, promoting oncogenic transformation. PMID: 20228808
- The reduction in CDC25A mRNA and protein was dependent on the cyclin-dependent kinase inhibitor p21 and miR-21, which were upregulated in HCT116 colon cancer cells during hypoxia. PMID: 19738433
- Results demonstrate by RNA interference that Sp1 regulates CDC25A and FAS expression and proliferation in cancer cells. PMID: 19621387
