Phospho-TP53 (S392) Antibody
Description
Definition and Applications
Phospho-TP53 (S392) Antibody is a monoclonal or polyclonal reagent designed to selectively recognize the phosphorylated form of p53 at serine 392. It is widely used to investigate p53 activation under genotoxic stress (e.g., UV radiation, camptothecin) and its role in transcription-independent apoptosis .
Key Applications:
| Technique | Recommended Dilution | Sample Types |
|---|---|---|
| Western blot | 1:500 – 1:2000 | MCF-7, HCT-116, HEK-293 cells |
| Immunofluorescence | 1:50 – 1:200 | Fixed cell lines (e.g., MCF-7) |
| ELISA | 1:2000 – 1:10000 | Purified phospho-p53 peptides |
Role of S392 Phosphorylation in p53 Function
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Mitochondrial Translocation: Phosphorylation at S392 enhances p53’s mitochondrial localization, enabling direct interaction with BAX/BAK to trigger cytochrome c release .
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DNA Damage Response: S392 phosphorylation increases after exposure to camptothecin (CPT) or doxorubicin (DOX), correlating with p53 stabilization and tetramer formation .
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Ubiquitination Regulation: UBE4B targets phospho-p53(S392) for degradation, modulating its tumor suppressor activity .
Biochemical Effects of S392 Phosphorylation
| Parameter | Wild-Type p53 | S392A Mutant | S392E Mutant |
|---|---|---|---|
| Mitochondrial Localization | High | Low | High |
| Apoptosis Induction | Strong | Weak | Strong |
| CPT Sensitivity | High | Reduced | High |
Mechanistic Insights:
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S392 phosphorylation does not affect p53’s transcriptional activity but is critical for its transcription-independent apoptotic function .
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Enrichment of phospho-S392 p53 in mitochondrial fractions (vs. nuclear) highlights its role in direct apoptosis signaling .
Limitations and Open Questions
Product Specs
Target Background
- This study summarizes the diverse functions of p53 in adipocyte development and adipose tissue homeostasis. Furthermore, it explores the manipulation of p53 levels in adipose tissue depots and the impact on systemic energy metabolism in the context of insulin resistance and obesity. [review] PMID: 30181511
- This research demonstrates that a USP15-dependent lysosomal pathway regulates p53-R175H turnover in ovarian cancer cells. PMID: 29593334
- The findings suggest that the mechanisms by which etoposide and ellipticine regulate CYP1A1 expression differ and might not solely involve p53 activation. PMID: 29471073
- This study investigated the association of tumor protein p53 and drug metabolizing enzyme polymorphisms with clinical outcomes in patients diagnosed with advanced nonsmall cell lung cancer. PMID: 28425245
- POH1 knockdown induced cell apoptosis through increased expression of p53 and Bim. PMID: 29573636
- This research uncovers a previously unknown effect of a chronic high-fat diet on beta-cells, where persistent oxidative stress results in p53 activation and subsequent inhibition of mRNA translation. PMID: 28630491
- Diffuse large B cell lymphoma lacking CD19 or PAX5 expression were more likely to harbor mutant TP53. PMID: 28484276
- This research indicates that proliferation potential-related protein promotes esophageal cancer cell proliferation and migration while suppressing apoptosis by mediating the expression of p53 and IL-17. PMID: 30223275
- Infection with HIV-1 and subsequent HIV-1 reverse transcription are inhibited in HCT116 p53(+/+) cells compared to HCT116 p53(-/-) cells. Tumor suppressor gene p53 expression is upregulated in non-cycling cells. The restriction of HIV by p53 is associated with the suppression of ribonucleotide reductase R2 subunit expression and phosphorylation of SAMHD1 protein. PMID: 29587790
- Studies have shown that MDM2 and MDMX are targetable vulnerabilities within TP53-wild-type T-cell lymphomas. PMID: 29789628
- A significant increase in the expression of p53 and Bax was observed in cells treated with alpha-spinasterol, while cdk4/6 were significantly down-regulated upon exposure to alpha-spinasterol. PMID: 29143969
- A significant correlation was found between telomere dysfunction indices, p53, oxidative stress indices, and malignant stages of gastrointestinal cancer patients. PMID: 29730783
- PGEA-AN modulates the P53 system, leading to the death of neuroblastoma cells without affecting the renal system in vivo, making it a promising candidate for developing anticancer agents against neuroblastoma. PMID: 29644528
- These data indicate that the activation of autophagy reduces the expression of STMN1 and p53, and the migration and invasion of cancer cells contribute to the anti-cancer effects of Halofuginone. These findings could provide new insights into breast cancer prevention and therapy. PMID: 29231257
- miR-150 suppresses cigarette smoke-induced lung inflammation and airway epithelial cell apoptosis, which is causally linked to the repression of p53 expression and NF-kappaB activity. PMID: 29205062
- Tumors harboring TP53 mutations, which can impair epithelial function, possess a unique bacterial consortium that is more abundant in smoking-associated tumors. PMID: 30143034
- Crosstalk among p53, lipid metabolism, insulin resistance, inflammation, and oxidative stress plays a role in Non-alcoholic fatty liver disease. [review] PMID: 30473026
- Ubiquitin-conjugating enzyme E2S (UBE2S) enhances the ubiquitination of p53 protein, facilitating its degradation in hepatocellular carcinoma (HCC) cells. PMID: 29928880
- p53 knockout compensates for osteopenia in murine Mysm1 deficiency. PMID: 29203593
- SIRT1 plays a pivotal protective role in regulating the aging and apoptosis of ADSCs induced by H2O2. PMID: 29803744
- 133p53 promotes tumor invasion via IL-6 through the activation of the JAK-STAT and RhoA-ROCK pathways. PMID: 29343721
- Mutant TP53 G245C and R273H can lead to more aggressive phenotypes and enhance cancer cell malignancy. PMID: 30126368
- PD-L1, Ki-67, and p53 staining individually have significant prognostic value for patients with stage II and III colorectal cancer. PMID: 28782638
- This study of patients with ccRCC, pooled analysis and multivariable modeling demonstrated that three recurrently mutated genes, BAP1, SETD2, and TP53, have statistically significant associations with poor clinical outcomes. Important clinical confounders, mutations of TP53 and SETD2 were associated with decreased CSS and RFS, respectively. PMID: 28753773
- The study revealed that the Wnt/beta-catenin signaling pathway and its major downstream target, c-Myc, increased the miR552 levels and miR552 directly targets the p53 tumor suppressor. miR552 may serve as an important link between the functional loss of APC, leading to abnormal Wnt signals, and the absence of p53 protein in colorectal cancer. PMID: 30066856
- High levels of glucose lead to endothelial dysfunction via TAF1-mediated p53 Thr55 phosphorylation and subsequent GPX1 inactivation. PMID: 28673515
- While tumor protein p53 (p53) does not directly control the luminal fate, its loss facilitates the acquisition of mammary stem cell (MaSC)-like properties by luminal cells and predisposes them to the development of mammary tumors with loss of luminal identity. PMID: 28194015
- Fifty-two percent of patients diagnosed with glioma/glioblastoma harbored a positive TP53 mutation. PMID: 29454261
- The expression of Ser216pCdc25C was also increased in the combined group, indicating that irinotecan likely radiosensitized the p53-mutant HT29 and SW620 cells through the ATM/Chk/Cdc25C/Cdc2 pathway. PMID: 30085332
- In the former, p53 binds to the CDH1 (encoding E-cadherin) locus to antagonize EZH2-mediated H3K27 trimethylation (H3K27me3) to maintain high levels of acetylation of H3K27 (H3K27ac). PMID: 29371630
- Among the hits, miR-596 was identified as a regulator of p53. Overexpression of miR-596 significantly increased p53 at the protein level, thereby inducing apoptosis. PMID: 28732184
- Apoptosis pathways are impaired in fibroblasts from patients with SSc, leading to chronic fibrosis. However, the PUMA/p53 pathway may not be involved in the dysfunction of apoptosis mechanisms in fibroblasts of patients with SSc. PMID: 28905491
- Low TP53 expression is associated with drug resistance in colorectal cancer. PMID: 30106452
- The activation of p38 in response to low doses of ultraviolet radiation was postulated to be protective for p53-inactive cells. Therefore, MCPIP1 may favor the survival of p53-defective HaCaT cells by sustaining the activation of p38. PMID: 29103983
- TP53 missense mutations are associated with castration-resistant prostate cancer. PMID: 29302046
- P53 degradation is mediated by COP1 in breast cancer. PMID: 29516369
- Combined inactivation of the XRCC4 non-homologous end-joining (NHEJ) DNA repair gene and p53 efficiently induces brain tumors with hallmark characteristics of human glioblastoma. PMID: 28094268
- This research establishes a direct link between Y14 and p53 expression, suggesting a function for Y14 in DNA damage signaling. PMID: 28361991
- TP53 Mutation is associated with Mouth Neoplasms. PMID: 30049200
- Cryo-Electron Microscopy studies on p53-bound RNA Polymerase II (Pol II) reveal that p53 structurally regulates Pol II to affect its DNA binding and elongation, providing new insights into p53-mediated transcriptional regulation. PMID: 28795863
- Increased nuclear p53 phosphorylation and PGC-1alpha protein content immediately following SIE but not CE suggests these may represent important early molecular events in the exercise-induced response to exercise. PMID: 28281651
- The E6/E7-p53-POU2F1-CTHRC1 axis promotes cervical cancer cell invasion and metastasis. PMID: 28303973
- Accumulated mutant-p53 protein suppresses the expression of SLC7A11, a component of the cystine/glutamate antiporter, system xC(-), through binding to the master antioxidant transcription factor NRF2. PMID: 28348409
- Consistently, forced expression of p53 significantly stimulated ACER2 transcription. Notably, p53-mediated autophagy and apoptosis were markedly enhanced by ACER2. Depletion of the essential autophagy gene ATG5 revealed that ACER2-induced autophagy facilitates its effect on apoptosis. PMID: 28294157
- Results indicate that LGASC of the breast is a low-grade triple-negative breast cancer that harbors a basal-like phenotype with no androgen receptor expression and shows a high rate of PIK3CA mutations but no TP53 mutations. PMID: 29537649
- This study demonstrates an inhibitory effect of wild-type P53 gene transfer on graft coronary artery disease in a rat model. PMID: 29425775
- Our findings suggest that TP53 c.215G>C, p. (Arg72Pro) polymorphism may be considered as a genetic marker for predisposition to breast cancer in the Moroccan population. PMID: 29949804
- Higher levels of the p53 isoform, p53beta, predict a better prognosis in patients with renal cell carcinoma by enhancing apoptosis in tumors. PMID: 29346503
- TP53 mutations are associated with colorectal liver metastases. PMID: 29937183
- High expression of TP53 is associated with oral epithelial dysplasia and oral squamous cell carcinoma. PMID: 29893337
Q&A
What is the biological significance of p53 phosphorylation at Serine 392?
Phosphorylation of p53 at Serine 392 plays multiple critical roles in p53 function:
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Enhanced mitochondrial translocation: S392 phosphorylation significantly promotes p53 localization to mitochondria, which is essential for its transcription-independent apoptotic function
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Increased in tumors: Phosphorylation at this site is elevated in human tumors
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Functional modulation: It influences growth suppressor function, DNA binding affinity, and transcriptional activation
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Stress response: Serves as a common phosphorylation event in response to diverse cellular stresses
Research in HCT-116 colon carcinoma cells demonstrated that while S392A mutants (non-phosphorylatable) displayed normal transcriptional activity, they showed markedly impaired mitochondrial localization and reduced apoptotic capacity, highlighting the importance of this modification .
What kinases are responsible for S392 phosphorylation?
Despite extensive research, the precise kinase(s) responsible for S392 phosphorylation remains incompletely defined:
Recent evidence suggests that "phosphorylation of S392 is not mediated by a UV-associated route involving p38 MAPK, either directly or indirectly via CK2" and may be phosphorylated by "an, as yet, unidentified protein kinase" . This represents an important knowledge gap in p53 regulation mechanisms.
What are the optimal protocols for detecting phospho-p53 (S392) in different cellular compartments?
Detection protocols must be tailored to specific cellular compartments:
Whole Cell Lysates:
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Western blotting using 1:1000 dilution of antibody is typically effective
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Treatment with phosphatase inhibitors is essential to prevent dephosphorylation during sample preparation
Mitochondrial Fractions:
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Isolation of clean mitochondrial fractions is critical
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P-S392 p53 is enriched in mitochondrial fractions after genotoxic stress
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Example protocol from literature: "After 4 and 8 h of exposure to CPT, mitochondrial fractions were isolated from wt and S392A HCT-116 cells, and the abundance of p53 was determined by western blot"
Immunofluorescence Detection:
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3 μg/mL antibody concentration with 3-hour room temperature incubation has been validated
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Nuclear and cytoplasmic staining patterns should be expected
How can I validate the specificity of a phospho-p53 (S392) antibody?
Multiple approaches should be used to ensure antibody specificity:
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Phosphatase treatment control: Treatment with lambda phosphatase should eliminate signal
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Genetic controls: Using cells expressing S392A mutant versus wild-type p53
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Induction controls: Compare treated versus untreated samples (e.g., camptothecin treatment induces S392 phosphorylation)
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Peptide competition: Using phosphorylated and non-phosphorylated peptides containing the S392 epitope
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Epitope verification: Confirm recognition of the epitope sequence "EGPDS[Phos]D"
As demonstrated in one study: "The phospho-specificity of this antibody was supported by decreased labeling following treatment with 600 U lambda-phosphatase (lambda-PPase) for 1 hour" .
How does S392 phosphorylation regulate p53 mitochondrial translocation and apoptosis?
The relationship between S392 phosphorylation and mitochondrial function is complex:
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Enrichment pattern: "P-S392 p53 was abundant in the mitochondrial fraction of [cell lines] while absent from the nuclei"
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Phosphomimetic studies: "In absence of stress (0 h), the fraction of p53 present in the mitochondrial fraction was higher for the S392E p53 form than for p53 wt and S392A"
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Direct correlation with apoptosis: "The decreased mitochondrial localization of the S392A mutant correlated with a lower ability to induce apoptosis"
These findings suggest S392 phosphorylation serves as a critical molecular switch directing p53 to mitochondria to initiate the direct apoptotic pathway. Notably, this function appears independent of p53's transcriptional activity.
What experimental models are optimal for studying S392 phosphorylation effects?
Several experimental models have proven valuable for S392 phosphorylation studies:
When choosing a model, consider: "The p53 form phosphorylated on S392 increases more slowly than the total p53 level. This could be due to a limiting kinase activity" .
How should phospho-p53 (S392) data be normalized and interpreted?
Proper data interpretation requires careful normalization and consideration of experimental variables:
For robust data interpretation, integrate findings from multiple detection methods and experimental approaches.
What explains contradictory findings regarding S392 phosphorylation in different studies?
Several factors may account for apparent contradictions in the literature:
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Cell type variations: Different cell lines may have distinct p53 regulatory networks
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Stress-specific responses: "Phosphorylation of Ser392 is an integral event that occurs not only in response to UV, but also during the induction of p53 by a range of stimuli"
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Technical differences: Antibody specificities, detection methods, and experimental timing all influence results
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Complex phosphorylation kinetics: "The fraction of p53, which is phosphorylated on S392 decreases with time" after initial stress
One significant contradiction involves the kinase responsible: while earlier studies implicated p38 MAPK, more recent evidence shows "Ser392 phosphorylation is not mediated by a UV-associated route involving p38 MAPK, either directly or indirectly via CK2" .
How do other post-translational modifications interact with S392 phosphorylation?
Analysis of post-translational modification interactions reveals:
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No clear association pattern: "No other post-translational modification was found to be enriched in the mitochondrial fraction" alongside P-S392
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Parallel modification: Phosphorylation of Ser392 and Ser33 was observed following induction of the p53 pathway by ARF
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Independence from ubiquitination: The ubiquitination profile appears similar between wild-type and S392A mutants
This suggests S392 phosphorylation may function independently from other modifications in regulating mitochondrial localization, though comprehensive studies mapping modification interactions are still needed.
What is the role of S392 phosphorylation in non-canonical p53 functions?
Beyond apoptosis, emerging evidence suggests broader roles for S392 phosphorylation:
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Metabolic regulation: Given p53's role in metabolism, S392 phosphorylation may influence metabolic pathways
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Tumor microenvironment interaction: Phosphorylation status may affect how p53 responds to microenvironmental cues
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Stress-specific functions: Different genotoxic stresses (UV, chemotherapeutics) may trigger distinct functional outcomes of S392 phosphorylation
These non-canonical functions remain active areas of investigation, with significant implications for understanding p53's diverse cellular roles.
