EPHA7 (Ab-791) Antibody

What is the EPHA7 (Ab-791) Antibody and what epitope does it recognize?

The EPHA7 (Ab-791) Antibody is a rabbit polyclonal antibody designed to detect endogenous levels of total human EPHA7 protein. It specifically recognizes an internal epitope of human EPHA7 that includes the region around tyrosine 791, which is a critical phosphorylation site . This antibody was developed using a synthesized peptide derived from the internal region of human EPHA7 as the immunogen, and was affinity-purified from rabbit antiserum using epitope-specific immunogen chromatography .

What is the significance of tyrosine 791 in EPHA7 function?

Tyrosine 791 represents a critical phosphorylation site in the EPHA7 receptor that mediates its signaling functions. Research has demonstrated that this specific residue is essential for EPHA7's tumor suppressive effects in prostate cancer models. Phosphorylation at tyrosine 791 is required for EPHA7's ability to inhibit cell proliferation, reduce invasiveness, and induce apoptosis in cancer cells . Studies using mutant EPHA7 constructs (where tyrosine 791 was rendered non-phosphorylatable) showed significant loss of these tumor suppressive functions, establishing tyrosine 791 as a key regulatory site for EPHA7 receptor activity .

How does EPHA7 signaling differ from other Eph receptor family members?

EPHA7 belongs to the Eph receptor tyrosine kinase family but exhibits distinctive signaling characteristics compared to other family members:

EPHA7's unique signaling profile contributes to its specific roles in development and disease contexts that may differ from other Eph family members .

What are the optimal conditions for using EPHA7 (Ab-791) Antibody in Western blotting applications?

For optimal Western blotting results with EPHA7 (Ab-791) Antibody, follow these methodological guidelines:

• Sample Preparation:

  • Extract total protein from cells using standard lysis buffers containing phosphatase inhibitors if phosphorylation status is important

  • Use 20-50 μg of total protein per lane

  • Denature samples in Laemmli buffer at 95°C for 5 minutes

• Gel Electrophoresis and Transfer:

  • Use 7-8% SDS-PAGE gels (EPHA7 is approximately 112 kDa)

  • Transfer to PVDF or nitrocellulose membrane at 100V for 90 minutes in cold transfer buffer

• Antibody Incubation:

  • Block membrane with 5% non-fat milk or BSA in TBST for 1 hour at room temperature

  • Dilute primary antibody 1:500-1:1000 in blocking buffer

  • Incubate overnight at 4°C with gentle rocking

  • Wash 3×15 minutes with TBST

  • Use appropriate HRP-conjugated secondary antibody (anti-rabbit) at 1:2000-1:5000 dilution

• Detection:

  • Develop using ECL substrate

  • Expected band size is approximately 112 kDa

Validation has been demonstrated in human cell lines including JK and K562 cells, where specificity was confirmed using peptide competition assays .

How should researchers design experiments to study EPHA7 phosphorylation at tyrosine 791?

To effectively study EPHA7 phosphorylation at tyrosine 791, consider this experimental design approach:

• Baseline Measurement:

  • Use EPHA7 (Ab-791) Antibody to detect total EPHA7 protein

  • In parallel, use phospho-specific antibodies targeting pTyr791 (commercially available )

  • Calculate phosphorylation ratio (pEPHA7/total EPHA7)

• Ligand Stimulation Experiments:

  • Treat cells with recombinant ephrinA5-Fc (2-5 μg/ml) for time-course experiments (0, 5, 15, 30, 60 minutes)

  • Include non-clustered Fc as negative control

  • Analyze phosphorylation changes by Western blotting

• Functional Models:

  • Compare wild-type EPHA7 with mutant constructs (Y791F mutant that cannot be phosphorylated)

  • Assess downstream effects on:

    • ERK phosphorylation

    • Akt dephosphorylation

    • Cell proliferation (EdU incorporation, Ki-67 staining)

    • Apoptosis (Annexin V/PI staining, caspase-3 activity)

• Cross-validation Approaches:

  • Immunoprecipitation followed by Western blot

  • Phospho-mass spectrometry for global phosphorylation analysis

  • Immunofluorescence to assess receptor clustering and localization

This methodological framework allows for comprehensive analysis of EPHA7 tyrosine 791 phosphorylation dynamics and its functional consequences .

How can EPHA7 (Ab-791) Antibody be utilized in studying the role of EPHA7 in leukemia progression?

The EPHA7 (Ab-791) Antibody can be instrumental in investigating EPHA7's role in leukemia through several advanced applications:

• Profiling ALL1-Fusion Protein Mechanisms:

  • Use the antibody to monitor EPHA7 expression in cells expressing ALL1/AF4 or ALL1/AF9 fusion proteins

  • Combine with ChIP assays to validate direct binding of ALL1 fusion proteins to the EPHA7 promoter

  • Correlate EPHA7 expression with ERK phosphorylation status in patient samples

• Treatment Response Monitoring:

  • Measure changes in EPHA7 expression and phosphorylation before and after ERK phosphorylation inhibitor treatment

  • Assess correlation between EPHA7 levels and apoptotic markers in t(4;11) leukemic cells

  • Create a phosphorylation profile panel including EPHA7 and downstream targets

• Biomarker Development:

  • Design tissue microarray studies using the antibody to evaluate EPHA7 expression across leukemia subtypes

  • Correlate expression with patient outcomes and treatment responses

  • Develop standardized scoring systems for EPHA7 expression patterns

The research by Nakanishi et al. demonstrated that EPHA7 is transcriptionally upregulated by ALL1 fusion proteins, and this upregulation is accompanied by ERK phosphorylation. This pathway represents a potential therapeutic vulnerability, as ERK phosphorylation blockers induced apoptotic cell death specifically in leukemic cells carrying the t(4;11) chromosome translocation .

What methodological approaches should be used to investigate the relationship between EPHA7 and downstream signaling pathways in cancer models?

To rigorously investigate EPHA7's relationships with downstream signaling pathways in cancer, implement these methodological approaches:

• Pathway Analysis Framework:

  • Simultaneous Multi-Pathway Profiling:

    • Western blot analysis of key nodes: PI3K/Akt (pAkt-Ser473, total Akt)

    • MAPK/ERK pathway (pERK1/2, total ERK)

    • Apoptotic mediators (Bcl-2, Bax, cleaved caspase-3)

  • Temporal Dynamics Assessment:

    • Time-course experiments following ephrinA5 stimulation (5-120 minutes)

    • Document sequential phosphorylation/dephosphorylation events

    • Develop pathway activation maps with temporal resolution

• Genetic Manipulation Strategies:

  • Comparative Analysis of EPHA7 Mutants:

    Construct	Description	Expected Effect on Signaling
    EPHA7-WT	Wild-type receptor	Normal phosphorylation and signaling
    EPHA7-Y791F	Mutation at critical phosphorylation site	Disrupted signaling, impaired tumor suppression
    EPHA7-ΔCyto	Deletion of cytoplasmic domain	Dominant negative, blocks downstream signaling
    EPHA7-KD	Kinase-dead mutant	Impaired catalytic activity

  • Pathway Perturbation Analysis:

    • Combine EPHA7 expression with selective pathway inhibitors

    • Measure rescue effects on phenotypes (proliferation, apoptosis)

    • Identify hierarchical relationships between pathways

• Advanced Phosphoproteomics:

  • Mass spectrometry-based phosphopeptide enrichment

  • SILAC or TMT labeling to quantify differential phosphorylation

  • Network analysis to identify novel EPHA7-dependent phosphorylation events

Research has established that phosphorylated EPHA7 suppresses prostate cancer malignancy through targeting PI3K/Akt signaling pathways, and these effects are enhanced by ephrinA5 ligand stimulation. These findings highlight the importance of properly assessing pathway relationships in understanding EPHA7's tumor suppressive functions .

How can researchers distinguish between specific and non-specific binding when using EPHA7 (Ab-791) Antibody?

To reliably distinguish between specific and non-specific binding when using EPHA7 (Ab-791) Antibody, implement these validation controls and analysis techniques:

• Essential Control Experiments:

  • Peptide Competition Assay: Pre-incubate the antibody with excess immunizing peptide (the synthesized peptide derived from internal region of EPHA7) before application to western blot or immunostaining. Disappearance of signal confirms specificity, as demonstrated in validation blots using JK and K562 cell extracts .

  • EPHA7 Knockdown/Knockout Controls: Compare antibody staining in:

    • Wild-type cells expressing endogenous EPHA7

    • EPHA7 siRNA/shRNA-treated cells (partial reduction)

    • EPHA7 CRISPR/Cas9 knockout cells (complete elimination)

  • Cross-Reactivity Assessment: Test antibody against recombinant EPHA7 and other EphA family members, particularly EphA4, which shares sequence similarity .

• Technical Optimization for Reducing Non-specific Binding:

  • Increase blocking stringency (5% BSA instead of milk for phospho-epitopes)

  • Optimize antibody dilution (1:500-1:1000 range)

  • Add 0.1-0.5% Triton X-100 to reduce hydrophobic interactions

  • Use gradual salt washes (150mM to 300mM NaCl in wash buffer)

• Signal Validation Criteria:

  • Molecular weight confirmation (EPHA7 should appear at ~112kDa)

  • Consistent band pattern across multiple cell lines with known EPHA7 expression

  • Comparison with alternative EPHA7 antibodies targeting different epitopes

• Advanced Authentication Methods:

  • Mass spectrometry validation of immunoprecipitated protein

  • Immunodepletion experiments (sequential immunoprecipitation)

  • Dual antibody detection (using antibodies against different EPHA7 epitopes)

These methodological approaches will help ensure the specificity of signals observed when using the EPHA7 (Ab-791) Antibody in research applications .

What are the potential pitfalls in interpreting EPHA7 phosphorylation data in tumor samples?

Interpreting EPHA7 phosphorylation data in tumor samples presents several methodological challenges researchers should address:

• Tissue Heterogeneity Considerations:

  • Cellular Composition Effects: Tumors contain multiple cell types (cancer cells, stroma, immune cells) with potentially different EPHA7 expression patterns

  • Mitigation Strategy: Use parallel immunohistochemistry with cell-type markers to identify EPHA7-expressing populations

  • Analysis Approach: Consider microdissection or single-cell approaches for heterogeneous samples

• Phosphorylation State Preservation Issues:

  • Technical Challenge: Phosphorylation states degrade rapidly ex vivo

  • Methodological Solution: Immediate snap-freezing or phosphatase inhibitor treatment

  • Validation Approach: Compare fresh vs. archived samples to assess phosphorylation stability

• Signaling Context Complexity:

  • Interpretation Challenge: EPHA7 phosphorylation exists within a network of compensatory pathways

  • Contextual Analysis: Measure multiple nodes in PI3K/Akt and MAPK pathways simultaneously

  • Comparative Approach: Assess phosphorylation ratios rather than absolute values

• Ephrin Ligand Expression Variability:

  • Biological Factor: EPHA7 phosphorylation depends on ephrinA5 ligand availability

  • Required Analysis: Parallel assessment of ephrinA5 expression in the same samples

  • Data Integration: Create ephrinA5/EPHA7 correlation matrices across samples

Research has demonstrated that in prostate cancer, EPHA7 phosphorylation was positively correlated with ephrinA5 expression in human tissues, highlighting the importance of analyzing both receptor and ligand. Furthermore, phosphorylation of EPHA7 was found to be dependent on ephrinA5-Fc stimulation, making the ligand context critical for proper data interpretation .

How might EPHA7 (Ab-791) Antibody be utilized in investigating EPHA7's role in neurological development and disorders?

EPHA7 (Ab-791) Antibody offers promising applications for investigating EPHA7's neurological functions:

• Neurodevelopmental Studies:

  • Application: Track EPHA7 expression and phosphorylation during critical neurodevelopmental windows

  • Methodology: Combine with brain section immunostaining to map regional expression patterns

  • Research Question: Does tyrosine 791 phosphorylation correlate with key neurodevelopmental events?

• Neuronal Migration Analysis:

  • Approach: Use ex vivo brain slice cultures treated with ephrinA5-Fc

  • Measurement: Assess EPHA7 phosphorylation status during neuronal migration

  • Correlation: Link phosphorylation patterns to cytoskeletal rearrangements and migration dynamics

• Synaptogenesis and Plasticity:

  • Experimental Setup: Primary neuronal cultures with varied activity levels

  • Analysis: Measure EPHA7 phosphorylation at synaptic compartments

  • Mechanistic Question: Does activity-dependent EPHA7 phosphorylation regulate synaptic refinement?

• Neurological Disorder Models:

  • Disease Relevance: Analyze EPHA7 phosphorylation in models of:

    • Neurodevelopmental disorders (autism spectrum disorders)

    • Neurodegenerative conditions (Alzheimer's)

    • Brain injury models (hypoxia-ischemia)

  • Therapeutic Potential: Test whether modulating EPHA7 phosphorylation affects disease progression

Recent spatial transcriptomics research has begun exploring EphA/ephrin signaling in neonatal brain injury contexts, suggesting potential roles for these pathways in neurological damage and recovery mechanisms .

What methodological approaches could be used to investigate the potential crosstalk between EPHA7 and chromatin remodeling complexes in cancer progression?

Emerging evidence suggests potential crosstalk between receptor tyrosine kinase signaling and chromatin regulation. To investigate EPHA7's interaction with chromatin remodeling machinery:

• Nuclear Localization Studies:

  • Technique: Subcellular fractionation followed by Western blotting with EPHA7 (Ab-791) Antibody

  • Analysis: Quantify cytoplasmic versus nuclear EPHA7 in response to ephrinA5 stimulation

  • Validation: Complementary immunofluorescence to visualize potential nuclear translocation

• Chromatin Association Analysis:

  • Methods: Chromatin immunoprecipitation (ChIP) using EPHA7 antibodies

  • Target Regions: Promoters of genes regulated in EPHA7-expressing versus deficient cells

  • Controls: Compare wild-type EPHA7 with Y791F phosphorylation-deficient mutant

• Protein-Protein Interaction Studies:

  • Approach: Immunoprecipitation-mass spectrometry to identify EPHA7 interactors

  • Focus: Screen for interactions with known chromatin remodeling complexes (SWI/SNF, NuRD)

  • Validation: Co-immunoprecipitation experiments with candidate interactors

• Functional Genomics Integration:

  • Design: Combine EPHA7 manipulation with chromatin accessibility assays (ATAC-seq)

  • Analysis: Identify genomic regions with altered accessibility following EPHA7 activation

  • Correlation: Link accessibility changes to transcriptional responses

Recent research has identified that ARID1A (a SWI/SNF complex component) can induce transcriptional reprogramming that rewires signaling pathways , while other studies have shown that ALL1 fusion proteins can regulate EPHA7 expression . These findings suggest potential mechanistic connections between EPHA7 signaling and chromatin regulation that warrant further investigation.

What are the most critical methodological factors researchers should consider when designing experiments using EPHA7 (Ab-791) Antibody?

When designing experiments with EPHA7 (Ab-791) Antibody, researchers should prioritize these methodological considerations:

• Epitope Accessibility:

  • The antibody targets an internal epitope around tyrosine 791, which may require optimal denaturation conditions in Western blotting

  • For applications involving native protein (immunoprecipitation), ensure buffer conditions preserve epitope structure

• Phosphorylation Dynamics:

  • Include phosphatase inhibitors in all sample preparation buffers

  • Consider parallel analysis with phospho-specific antibodies targeting pTyr791

  • Implement time-course experiments to capture transient phosphorylation events

• Experimental Controls Hierarchy:

  • Essential controls: Peptide competition, EPHA7-deficient cells/tissues

  • Validation controls: Multiple antibodies targeting different EPHA7 epitopes

  • Functional controls: Comparison of wild-type vs. Y791F mutant effects

• Contextual Factors:

  • EphrinA5 ligand availability significantly impacts EPHA7 phosphorylation and function

  • Cell density affects Eph-ephrin interactions (contact-dependent signaling)

  • Cellular background influences EPHA7 signaling outcomes (tumor suppressive vs. oncogenic)