Phospho-BRCA1 (Ser1457) Antibody

What is the specific epitope recognized by Phospho-BRCA1 (Ser1457) Antibody?

The Phospho-BRCA1 (Ser1457) antibody specifically recognizes the BRCA1 protein when phosphorylated at serine 1457. According to the immunogen information, the antibody was produced against a synthesized phosphopeptide derived from human BRCA1 around the phosphorylation site of serine 1457, with the sequence L-T-SP-Q-K (where SP represents the phosphorylated serine) . This specificity ensures that the antibody only detects endogenous levels of BRCA1 when phosphorylated at this particular residue and not unphosphorylated BRCA1 or other phosphorylation sites . When designing experiments, researchers should consider that the epitope recognition depends on the phosphorylation status, making this antibody valuable for studying post-translational modifications of BRCA1.

What applications are validated for Phospho-BRCA1 (Ser1457) Antibody?

The Phospho-BRCA1 (Ser1457) antibody has been validated for the following applications:

While Western blot is the primary application across all vendors , the antibody shows strong performance in ELISA applications as well. When conducting Western blot analysis, researchers should optimize the dilution within the recommended range based on their specific experimental conditions and sample types. For accurate phosphorylation detection, always include appropriate controls and consider using phosphatase inhibitors during sample preparation to prevent dephosphorylation during lysate handling.

What is the optimal storage protocol for maintaining antibody activity?

To maintain optimal activity of the Phospho-BRCA1 (Ser1457) antibody, follow these storage guidelines:

• Long-term storage: Store at -20°C for up to one year . Aliquot the antibody upon first use to avoid repeated freeze-thaw cycles.

• Short-term storage (frequent use): Store at 4°C for up to one month .

• Avoid repeated freeze-thaw cycles as they can degrade the antibody and reduce sensitivity .

• The antibody is typically supplied in PBS containing 50% glycerol, 0.5% BSA, and 0.02% sodium azide , which helps maintain stability during storage.

Researchers should monitor antibody performance over time. If signal intensity decreases, this may indicate antibody degradation, requiring fresh aliquots or replacement.

What is the molecular weight of phosphorylated BRCA1 detected by this antibody?

The phosphorylated BRCA1 protein detected by this antibody has the following molecular weights:

The calculated molecular weight of BRCA1 is approximately 207-208 kDa , but the observed molecular weight on Western blots is typically around 220 kDa . This discrepancy is common for large proteins and can be attributed to post-translational modifications, including phosphorylation, which can affect protein migration during SDS-PAGE. When analyzing Western blot results, researchers should look for bands at approximately 220 kDa, while being aware that different gel conditions and sample preparations might slightly affect the apparent molecular weight.

What positive and negative controls should be used with this antibody?

For reliable phospho-specific antibody experiments, the following controls are recommended:

Positive Controls:

• Cell lysates from cells treated with DNA-damaging agents (e.g., UV radiation, γ-irradiation, or hydroxyurea), which induce BRCA1 phosphorylation

• Recombinant phosphorylated BRCA1 protein (if available)

Negative Controls:

• Samples treated with lambda phosphatase to remove phosphorylations

• Cell lysates from BRCA1-knockout cell lines

• Primary antibody omission (for non-specific secondary antibody binding)

• Blocking with the immunizing phosphopeptide

Implementing these controls helps validate antibody specificity and ensures that the observed signal is truly representative of phosphorylated BRCA1 at Ser1457. This is particularly important when studying phosphorylation events that may be transient or condition-dependent.

How does Ser1457 phosphorylation relate to BRCA1's tumor suppressor function?

Phosphorylation at Ser1457 is one of several key post-translational modifications that regulate BRCA1's tumor suppressor activities. BRCA1 functions as part of a large multi-subunit protein complex known as BASC (BRCA1-associated genome surveillance complex) that plays crucial roles in maintaining genomic stability . The Ser1457 phosphorylation site is located in a region that interfaces with DNA repair machinery and transcriptional regulatory complexes.

Current research indicates that:

• Phosphorylation at Ser1457 may influence BRCA1's interaction with RNA polymerase II and histone deacetylase complexes

• This modification potentially regulates BRCA1's role in transcription, DNA repair of double-stranded breaks, and recombination

• Altered phosphorylation patterns at this site may contribute to disrupted tumor suppressor function

When investigating BRCA1's tumor suppressor activities, researchers should consider analyzing Ser1457 phosphorylation status in conjunction with other key phosphorylation sites to develop a comprehensive understanding of BRCA1 regulation in normal versus cancer cells.

What experimental approaches can detect dynamic changes in BRCA1 Ser1457 phosphorylation?

To monitor dynamic changes in BRCA1 Ser1457 phosphorylation following cellular stresses or during cell cycle progression, consider these methodological approaches:

Time-course experiments:

• Treat cells with DNA-damaging agents (e.g., ionizing radiation, etoposide)

• Harvest cells at multiple time points (0, 15, 30, 60, 120, 240 minutes)

• Perform Western blot analysis using the Phospho-BRCA1 (Ser1457) antibody

• Normalize phospho-signal to total BRCA1 levels using a pan-BRCA1 antibody

Cell synchronization protocols:

• Synchronize cells at different cell cycle stages using established methods:

  • G1/S boundary: Double thymidine block

  • G2/M: Nocodazole treatment

  • M phase: Mitotic shake-off

• Confirm synchronization efficiency using flow cytometry

• Analyze Ser1457 phosphorylation status at each stage

This approach allows researchers to correlate Ser1457 phosphorylation with specific cellular states and stress responses, providing insights into the regulatory mechanisms controlling BRCA1 function.

What kinases are implicated in BRCA1 Ser1457 phosphorylation?

While the specific kinases responsible for BRCA1 Ser1457 phosphorylation are not directly mentioned in the provided search results, based on the consensus sequence context (L-T-S-Q-K) and BRCA1 biology, several kinases warrant investigation:

To identify the responsible kinase(s), researchers could:

• Perform in vitro kinase assays with recombinant kinases and BRCA1 substrates

• Use specific kinase inhibitors followed by Western blot with the Phospho-BRCA1 (Ser1457) antibody

• Employ genetic approaches (siRNA, CRISPR) to deplete candidate kinases

Understanding the kinases responsible for this phosphorylation event would provide valuable insights into the signaling pathways regulating BRCA1 function in different cellular contexts.

How can Phospho-BRCA1 (Ser1457) Antibody be used in multiplex immunoassays?

For comprehensive analysis of BRCA1 phosphorylation and its protein interaction network, multiplex approaches with Phospho-BRCA1 (Ser1457) antibody can be valuable:

Multiplex Western blotting:

• Perform sequential probing with antibodies recognizing different BRCA1 phosphorylation sites

• Use fluorescent secondary antibodies with distinct emission spectra

• Strip and reprobe membranes carefully, validating complete stripping between rounds

Co-immunoprecipitation (Co-IP) strategies:

• Immunoprecipitate using Phospho-BRCA1 (Ser1457) antibody

• Analyze precipitates for interacting partners specific to this phosphorylation state

• Compare interactomes between phosphorylated and non-phosphorylated BRCA1

Proximity ligation assay (PLA):

• Use Phospho-BRCA1 (Ser1457) antibody in combination with antibodies against potential interacting proteins

• PLA signal indicates proximity (<40 nm) between the two proteins

• This approach provides spatial information about interactions in situ

These multiplex approaches allow researchers to simultaneously analyze multiple aspects of BRCA1 biology, providing a more comprehensive understanding of its regulation and function.

What are potential troubleshooting strategies for Western blots using this antibody?

When optimizing Western blots with Phospho-BRCA1 (Ser1457) antibody, researchers may encounter several challenges:

Additionally:

• For large proteins like BRCA1 (~220 kDa), use lower percentage gels (6-8%) for better resolution

• Consider longer transfer times for complete transfer of large proteins

• When studying phosphorylation dynamics, timing of cell harvesting is critical as phosphorylation events may be transient

Implementing these troubleshooting strategies can help obtain clear, specific signals when using the Phospho-BRCA1 (Ser1457) antibody in Western blot applications.

How does Ser1457 phosphorylation status differ between normal and cancer cells?

Understanding the differential phosphorylation of BRCA1 at Ser1457 between normal and cancer cells provides insights into disease mechanisms:

While specific data on Ser1457 phosphorylation patterns in cancer versus normal cells is limited in the provided search results, several research approaches can address this question:

• Compare phosphorylation levels between matched normal and tumor tissues using Western blot or immunohistochemistry

• Analyze phosphorylation status in normal breast epithelial cell lines versus breast cancer cell lines with varying BRCA1 mutation status

• Investigate how Ser1457 phosphorylation correlates with:

  • BRCA1 isoform expression (noting that isoform 3 is reduced in breast and ovarian cancer cell lines )

  • DNA repair efficiency

  • Genomic instability markers

Research implications: Altered phosphorylation at Ser1457 may serve as a biomarker for BRCA1 dysfunction in cancer cells even in the absence of mutations. This could potentially provide new diagnostic approaches or therapeutic targets in BRCA1-associated cancers.

What sample preparation methods optimize detection of phosphorylated BRCA1?

To maximize detection of phosphorylated BRCA1 at Ser1457, follow these sample preparation guidelines:

Lysis buffer composition:

• Include phosphatase inhibitors (e.g., sodium fluoride, sodium orthovanadate, β-glycerophosphate)

• Add protease inhibitors to prevent degradation of BRCA1 (MW ~220 kDa)

• Consider RIPA or NP-40-based buffers for nuclear proteins like BRCA1

Sample handling:

• Keep samples cold throughout preparation

• Process samples quickly to minimize dephosphorylation

• Avoid multiple freeze-thaw cycles of lysates

Enrichment strategies:

• Consider phosphoprotein enrichment techniques for low-abundance phosphorylated forms

• Nuclear fractionation may increase signal-to-noise ratio for BRCA1 detection

These optimized sample preparation techniques help preserve the phosphorylation status of BRCA1 at Ser1457, enabling more accurate analysis of this post-translational modification under various experimental conditions.

How can quantitative analysis of BRCA1 Ser1457 phosphorylation be performed?

For rigorous quantitative analysis of BRCA1 Ser1457 phosphorylation:

Western blot quantification:

• Use digital imaging systems rather than film for wider linear detection range

• Always normalize phospho-BRCA1 (Ser1457) to total BRCA1 levels

• Include calibration standards when possible

• Perform technical replicates (minimum of three)

Alternative quantitative approaches:

• ELISA-based methods (recommended dilution 1:5000)

  • Develop sandwich ELISA using capture antibody against total BRCA1

  • Detect with Phospho-BRCA1 (Ser1457) antibody

• Quantitative mass spectrometry

  • Immunoprecipitate BRCA1 and analyze phosphopeptides

  • Use heavy-labeled synthetic phosphopeptides as internal standards

Data analysis considerations:

• Apply appropriate statistical tests based on experimental design

• Report both absolute and relative changes in phosphorylation

• Consider the biological context when interpreting quantitative changes

These quantitative approaches allow researchers to detect subtle changes in BRCA1 phosphorylation status that might have significant biological implications in different cellular contexts.

What cross-reactivity considerations should be addressed when using this antibody?

While the Phospho-BRCA1 (Ser1457) antibody is designed to be specific, researchers should consider potential cross-reactivity issues:

Species cross-reactivity:

• Confirmed reactivity: Human

• Predicted cross-reactivity: Pig, Bovine, Dog, Chicken

• When using the antibody in non-human systems, validation experiments are essential

Epitope similarity concerns:

• Proteins with similar phosphorylation motifs may cross-react

• Perform specificity controls:

  • BRCA1 knockdown/knockout validation

  • Peptide competition assays with phospho and non-phospho peptides

  • Dephosphorylation controls

Isoform considerations:

• BRCA1 has multiple isoforms; isoform 1 and isoform 3 are widely expressed

• Note that isoform 3 is reduced or absent in several breast and ovarian cancer cell lines

• Verify that the Ser1457 site is present in the specific isoforms being studied

Addressing these cross-reactivity considerations ensures that experimental results truly reflect BRCA1 Ser1457 phosphorylation status rather than non-specific signals or artifacts.

How can Phospho-BRCA1 (Ser1457) Antibody be used to study DNA damage response pathways?

The Phospho-BRCA1 (Ser1457) antibody serves as a valuable tool for investigating DNA damage response (DDR) pathways:

Experimental design for DNA damage studies:

• Treat cells with DNA-damaging agents:

  • Double-strand breaks: Ionizing radiation, etoposide, bleomycin

  • Replication stress: Hydroxyurea, aphidicolin

  • Cross-linking damage: Cisplatin, mitomycin C

• Monitor Ser1457 phosphorylation kinetics by Western blot

• Correlate phosphorylation with:

  • Recruitment to DNA damage foci (by immunofluorescence)

  • Interaction with other DDR proteins (by co-immunoprecipitation)

  • Functional readouts of DNA repair (comet assay, HR/NHEJ reporter assays)

Integration with other DDR markers:

• γH2AX (double-strand break marker)

• RAD51 (homologous recombination)

• 53BP1 (non-homologous end joining)

Understanding how Ser1457 phosphorylation correlates with these established DDR markers can provide insights into the specific role of this modification in regulating BRCA1's function in DNA repair pathways.

What immunohistochemistry protocols work best with Phospho-BRCA1 (Ser1457) Antibody?

While the search results primarily indicate Western blot as the validated application for this antibody , researchers interested in immunohistochemistry (IHC) applications might consider the following optimization strategy:

IHC protocol optimization:

• Tissue preparation:

  • Use freshly fixed tissues (10% neutral buffered formalin, 24h)

  • Consider phospho-epitope retrieval techniques:

    • Heat-induced epitope retrieval (HIER) with citrate buffer (pH 6.0)

    • Try alternative buffers if needed (EDTA, pH 8.0)

• Antibody conditions:

  • Start with dilutions in the 1:50-1:200 range

  • Incubate overnight at 4°C to maximize sensitivity

  • Use amplification systems if needed (HRP-polymer, TSA)

• Controls:

  • Phosphatase-treated serial sections (negative control)

  • Tissues known to have activated DNA damage response (positive control)

  • Peptide competition controls

When developing IHC protocols, researchers should thoroughly validate specificity through these controls before interpreting results in experimental or clinical samples.

How does BRCA1 Ser1457 phosphorylation interact with other post-translational modifications?

BRCA1 function is regulated by a complex network of post-translational modifications, with Ser1457 phosphorylation representing one component of this regulatory system:

Integrated analysis approaches:

• Multisite phosphorylation analysis:

  • Compare phosphorylation kinetics at Ser1457 with other key sites (e.g., Ser1423, Ser1524)

  • Use phospho-specific antibodies to multiple sites in parallel experiments

  • Consider mass spectrometry approaches for comprehensive phosphorylation profiling

• Cross-talk with other modifications:

  • Ubiquitination (BRCA1 has E3 ubiquitin ligase activity)

  • SUMOylation (modulates BRCA1 localization)

  • Acetylation (affects chromatin association)

• Functional readouts:

  • Protein-protein interactions affected by modification status

  • Subcellular localization changes

  • DNA repair efficiency

Understanding the interplay between Ser1457 phosphorylation and other modifications provides a more complete picture of how BRCA1 function is fine-tuned in response to cellular stresses and cell cycle progression.

What emerging technologies could enhance studies using Phospho-BRCA1 (Ser1457) Antibody?

Several cutting-edge technologies can extend the utility of Phospho-BRCA1 (Ser1457) antibody in research:

Single-cell phosphoproteomics:

• Apply Phospho-BRCA1 (Ser1457) antibody in single-cell Western blot platforms

• Analyze cell-to-cell variation in phosphorylation status

• Correlate with other single-cell parameters (cell cycle, DNA damage)

Live-cell imaging approaches:

• Develop phospho-specific intrabodies based on the Phospho-BRCA1 (Ser1457) antibody

• Monitor phosphorylation dynamics in real-time

• Correlate with BRCA1 localization and function

CRISPR-based phosphosite engineering:

• Generate Ser1457 phosphomimetic (S1457D/E) or phospho-dead (S1457A) mutants

• Compare phenotypes to wild-type BRCA1

• Validate antibody specificity against these engineered cell lines

These emerging technologies can provide unprecedented insights into the spatial and temporal dynamics of BRCA1 Ser1457 phosphorylation and its functional consequences in various cellular contexts.

How might Phospho-BRCA1 (Ser1457) analysis contribute to precision oncology?

Understanding BRCA1 Ser1457 phosphorylation status has potential implications for precision oncology approaches:

Biomarker development:

• Investigate whether altered Ser1457 phosphorylation correlates with:

  • Tumor subtypes or stages

  • Treatment responses

  • Patient outcomes

• Develop quantitative assays suitable for clinical samples

Therapeutic targeting:

• Identify kinases/phosphatases regulating Ser1457 phosphorylation

• Explore whether modulating this phosphorylation affects:

  • Sensitivity to PARP inhibitors

  • Response to platinum-based chemotherapy

  • Efficacy of radiation therapy

Patient stratification:

• Determine if Ser1457 phosphorylation status could identify:

  • Patients likely to respond to specific therapies

  • Tumors with defective DNA repair despite wild-type BRCA1 sequence

  • Early indicators of treatment resistance

These research directions could potentially translate fundamental knowledge about BRCA1 Ser1457 phosphorylation into clinically relevant applications for cancer diagnosis, prognosis, and treatment.