Phospho-NTRK1 (Y680/Y681) Antibody

What is Phospho-NTRK1 (Y680/Y681) Antibody and what does it detect?

Phospho-NTRK1 (Y680/Y681) Antibody is a polyclonal antibody that specifically detects endogenous levels of NTRK1 (also known as TrkA) protein only when phosphorylated at tyrosine residues 680 and 681 . This antibody recognizes the phosphorylated form of NTRK1, which is a high-affinity nerve growth factor receptor involved in the development and function of the cholinergic nervous system . The antibody is typically raised in rabbits using a synthesized peptide derived from human NTRK1 around the phosphorylation site of Y680/Y681 .

The specificity for the phosphorylated form is critical because NTRK1 phosphorylation at Y680/Y681 occurs during receptor activation following ligand binding, making this antibody valuable for monitoring NTRK1 activation status in experimental systems .

What are the recommended applications for Phospho-NTRK1 (Y680/Y681) Antibody?

The Phospho-NTRK1 (Y680/Y681) Antibody has been validated for several research applications:

• Western Blotting (WB): The antibody can be used at dilutions ranging from 1:500 to 1:2000 for detecting phosphorylated NTRK1 in protein lysates .

• Enzyme-Linked Immunosorbent Assay (ELISA): The antibody is effective at a dilution of approximately 1:5000 for ELISA applications .

While these are the primary validated applications, researchers should perform optimization experiments when adapting the antibody for other techniques such as immunohistochemistry (IHC) or immunoprecipitation (IP). Validation with proper controls is essential when expanding the application range of this antibody .

What species reactivity does the Phospho-NTRK1 (Y680/Y681) Antibody exhibit?

The Phospho-NTRK1 (Y680/Y681) Antibody has been validated to react with NTRK1 from multiple species including:

• Human (Homo sapiens)

• Mouse (Mus musculus)

• Rat (Rattus norvegicus)

This cross-reactivity makes the antibody valuable for comparative studies across different model organisms. The conservation of the epitope region containing Y680/Y681 across these species enables consistent detection performance. When working with other species not listed, researchers should conduct preliminary validation experiments to confirm reactivity before proceeding with full-scale studies .

How should Phospho-NTRK1 (Y680/Y681) Antibody be stored and handled?

For optimal performance and longevity of the Phospho-NTRK1 (Y680/Y681) Antibody, follow these storage and handling guidelines:

• Storage temperature: Upon receipt, store at -20°C or -80°C for long-term stability .

• Storage buffer: The antibody is typically supplied in PBS containing 50% glycerol, 0.5% BSA, and 0.02% sodium azide as preservatives .

• Avoid repeated freeze-thaw cycles: Aliquot the antibody upon first thaw to minimize degradation from multiple freeze-thaw cycles .

• Working dilutions: Prepare working dilutions fresh before use and store at 4°C for short periods (1-2 weeks) if necessary.

• Sodium azide warning: Note that the storage buffer contains sodium azide, which is toxic and can form explosive compounds in metal plumbing. Dispose of according to local regulations .

How can researchers validate the specificity of Phospho-NTRK1 (Y680/Y681) Antibody?

Validating antibody specificity is critical for ensuring reliable research results. For Phospho-NTRK1 (Y680/Y681) Antibody, consider these validation approaches:

• Knockout/knockdown controls: Use NTRK1 knockout tissues or cells as negative controls. As demonstrated in research with Ntrk1 knockout mice, specific antibody signals should be absent in knockout samples .

• Phosphatase treatment: Treat half of your sample with lambda phosphatase before immunoblotting. The signal should disappear in the treated sample if the antibody is phospho-specific.

• Ligand stimulation: Compare samples with and without NGF stimulation. NGF treatment increases NTRK1 phosphorylation, so signal intensity should increase in stimulated samples .

• Inhibitor treatment: Use NTRK1 inhibitors like AZD4547 or LOXO195. Treatment should reduce or eliminate the phospho-NTRK1 signal in a dose-dependent manner .

• Peptide competition assay: Pre-incubate the antibody with the immunizing phosphopeptide, which should block specific binding and eliminate true signals.

These validation methods help distinguish specific signals from non-specific background, crucial for accurate data interpretation and reproducible results.

What are the key signaling pathways downstream of phosphorylated NTRK1 (Y680/Y681)?

Phosphorylation of NTRK1 at Y680/Y681 activates several major signaling cascades that regulate neuronal survival, differentiation, and function:

• PLC-gamma pathway: Phosphorylated NTRK1 activates phospholipase C-gamma, leading to the generation of inositol trisphosphate (IP3) and diacylglycerol (DAG), which regulate calcium signaling and PKC activation .

• PI3K-AKT pathway: NTRK1 phosphorylation leads to activation of the PI3K-AKT pathway through SHC1 and SH2B1, promoting cell survival signaling .

• Ras-MAPK pathway: Through SHC1 and FRS2, phosphorylated NTRK1 activates the GRB2-Ras-MAPK cascade, which regulates cell differentiation and survival .

• Hippo pathway regulation: Research has revealed that NTRK1 positively regulates YAP oncogenic function by modulating LATS1 phosphorylation, creating an important crosstalk between NGF-NTRK1 and Hippo cancer pathways .

When using the Phospho-NTRK1 (Y680/Y681) Antibody to study these pathways, researchers should consider examining multiple downstream effectors simultaneously to understand the broader signaling context.

How can Phospho-NTRK1 (Y680/Y681) Antibody be used to investigate cancer mechanisms?

The Phospho-NTRK1 (Y680/Y681) Antibody serves as a valuable tool for investigating NTRK1's role in cancer progression and therapeutic response:

• Monitoring treatment efficacy: Track changes in NTRK1 phosphorylation status following treatment with targeted inhibitors like AZD4547. Complete inhibition of NTRK1 phosphorylation has been observed at 1 μM of AZD4547 in cancer cells harboring NTRK1 fusions .

• Investigating signaling crosstalk: Study the interaction between NTRK1 and the Hippo pathway, particularly how NTRK1 inhibition affects YAP phosphorylation and subcellular localization. This approach revealed that NTRK1 inhibition augments YAP cytoplasmic localization and suppresses YAP target gene expression .

• Analyzing fusion proteins: In cancers with TPM3-NTRK1 or other NTRK1 fusions, use the antibody to assess the phosphorylation status and activation of these oncogenic fusion proteins .

• Pathway profiling: Combine phospho-NTRK1 detection with analysis of downstream effectors (p-PLC-gamma, p-AKT, p-MEK1/2, p-ERK) to create comprehensive pathway activation profiles in cancer specimens .

• Target gene expression analysis: Correlate NTRK1 phosphorylation with expression of downstream target genes such as DUSP6, ETV1, E2F1, and CCND1, which are regulated by NTRK1 signaling .

This approach provides mechanistic insights into NTRK1's role in cancer and helps identify potential therapeutic strategies targeting NTRK1 or its downstream pathways.

What technical challenges exist in detecting phosphorylated NTRK1 in complex tissue samples?

Detecting phosphorylated NTRK1 in complex tissue samples presents several technical challenges that researchers should address:

• Low abundance issue: Phosphorylated NTRK1 may be present at low levels, requiring sensitive detection methods and optimal sample preparation. Enrichment techniques such as immunoprecipitation may be necessary before Western blotting .

• Rapid dephosphorylation: Phosphorylated proteins are susceptible to rapid dephosphorylation by endogenous phosphatases during sample preparation. Include phosphatase inhibitors in all buffers and keep samples cold throughout processing .

• Antibody specificity: As demonstrated in studies with Ntrk1 knockout mice, many commercial antibodies lack specificity. Validate the Phospho-NTRK1 (Y680/Y681) Antibody in your specific experimental system using appropriate controls .

• Cell-type specific expression: NTRK1 is expressed in specific cell populations within tissues (e.g., cholinergic neurons in basal forebrain, striatum, and paraventricular thalamic nucleus), making it challenging to detect in whole tissue lysates where these cells constitute a small fraction of the total cell population .

• Interference from other phosphoproteins: Tissues contain numerous phosphoproteins that might cross-react with the antibody. Careful blocking and washing steps are essential for reducing background signals .

Including region-specific microdissection or single-cell analysis techniques can help overcome these challenges when studying heterogeneous tissues.

How do NGF stimulation and inhibitor treatment affect NTRK1 phosphorylation at Y680/Y681?

NGF stimulation and inhibitor treatment have opposing effects on NTRK1 phosphorylation at Y680/Y681, which can be monitored using the Phospho-NTRK1 (Y680/Y681) Antibody:

NGF Stimulation Effects:

• Increased receptor phosphorylation: NGF binding to NTRK1 induces receptor dimerization and autophosphorylation at multiple tyrosine residues, including Y680/Y681 .

• Temporal phosphorylation pattern: NGF treatment decreases p-LATS1 and increases NTRK1 phosphorylation in a time-dependent manner .

• Downstream activation: Following NGF stimulation, increased NTRK1 phosphorylation leads to upregulation of YAP target genes (CTGF, CYR61, ANKRD1) and enhanced cell proliferation and migration .

• Nuclear translocation effects: NGF treatment causes YAP translocation into the nucleus, promoting transcriptional activity .

Inhibitor Treatment Effects:

• Dose-dependent inhibition: NTRK1 inhibitors like AZD4547 block NTRK1 phosphorylation in a dose-dependent manner, with complete abolishment observed at 1 μM concentration .

• Downstream pathway suppression: Inhibitor treatment leads to decreased phosphorylation of downstream effectors including PLC-gamma, AKT, MEK1/2, and ERK .

• Target gene suppression: NTRK1 inhibition downregulates MAPK target genes including ETV1, DUSP6, E2F1, and CCND1 .

These opposing effects provide useful experimental paradigms for studying NTRK1 signaling dynamics and validating antibody performance.

What are the optimal Western blotting conditions for Phospho-NTRK1 (Y680/Y681) Antibody?

For optimal Western blotting results with Phospho-NTRK1 (Y680/Y681) Antibody, follow these methodological considerations:

• Sample preparation:

  • Include phosphatase inhibitors (sodium orthovanadate, sodium fluoride, etc.) in lysis buffers

  • Process samples quickly at 4°C to minimize dephosphorylation

  • Use SDS-PAGE sample buffer with fresh DTT or β-mercaptoethanol

• Gel electrophoresis:

  • 8-10% polyacrylamide gels are optimal for resolving NTRK1 (140 kDa)

  • Include phosphorylated control samples (e.g., NGF-stimulated cells)

• Transfer conditions:

  • Use PVDF membrane for better protein retention

  • Transfer at low amperage overnight at 4°C for high molecular weight proteins

• Blocking:

  • 5% BSA in TBST (not milk, which contains phosphatases) for 1 hour at room temperature

• Primary antibody incubation:

  • Dilute antibody 1:500-1:2000 in 5% BSA/TBST

  • Incubate overnight at 4°C with gentle agitation

• Detection system:

  • HRP-conjugated anti-rabbit secondary antibody at 1:5000-1:10000

  • ECL substrate optimized for phosphoprotein detection

• Stripping and reprobing:

  • For complete analysis, strip and reprobe with total NTRK1 antibody to calculate phosphorylation/total protein ratio

Following these optimized conditions will help ensure specific detection of phosphorylated NTRK1 while minimizing background signals.

What control samples should be included when using Phospho-NTRK1 (Y680/Y681) Antibody?

Including appropriate controls is essential for reliable interpretation of results when using Phospho-NTRK1 (Y680/Y681) Antibody:

• Positive controls:

  • NGF-stimulated cells/tissues (e.g., PC12 cells, sensory neurons) to demonstrate increased phosphorylation

  • Cell lines known to express phosphorylated NTRK1 (e.g., KM12 cells with TPM3-NTRK1 fusion)

• Negative controls:

  • NTRK1 knockout or knockdown samples to validate antibody specificity

  • Unstimulated cells (serum-starved) to establish baseline phosphorylation levels

  • Tissues known to lack NTRK1 expression as anatomical negative controls

• Treatment controls:

  • Phosphatase-treated samples to confirm phospho-specificity

  • NTRK1 inhibitor-treated samples (e.g., AZD4547, LOXO195) to demonstrate signal reduction

  • Dose-dependent inhibitor treatment to show gradient response

• Technical controls:

  • Secondary antibody-only controls to identify non-specific binding

  • Loading controls (β-actin, GAPDH) to normalize protein amounts

  • Total NTRK1 detection on parallel blots to calculate phospho/total ratios

This comprehensive control strategy enables confident interpretation of experimental results and helps troubleshoot technical issues that may arise.

Quantification Methods:

• Densitometric analysis: Use image analysis software (ImageJ, Image Studio, etc.) to quantify band intensities from Western blots.

• Normalization approaches:

  • Normalize phospho-NTRK1 signal to total NTRK1 to account for expression differences

  • Additionally normalize to loading controls (β-actin, GAPDH) for equal loading verification

  • Present data as fold change relative to baseline or control conditions

• Statistical analysis:

  • Perform experiments in biological triplicates minimum

  • Apply appropriate statistical tests based on experimental design

  • Report p-values and confidence intervals for significance determination

Interpretation Guidelines:

• Phosphorylation dynamics: NTRK1 phosphorylation is dynamic and context-dependent. Interpret signals in relation to stimulation time, inhibitor concentration, and cellular context .

• Pathway integration: Correlate phospho-NTRK1 (Y680/Y681) with downstream effectors (p-PLC-gamma, p-AKT, p-ERK) to understand pathway activation more comprehensively .

• Biological relevance: Connect phosphorylation changes to functional outcomes like proliferation, migration, or transcriptional changes measured in parallel experiments .

• Threshold considerations: Determine the threshold of phosphorylation required for biological effects through dose-response experiments.

• Cellular localization: Consider that phosphorylated NTRK1 may localize to specific cellular compartments, affecting signal interpretation in whole-cell lysates.

This systematic approach to quantification and interpretation enhances the reliability and biological relevance of research findings.

How can Phospho-NTRK1 (Y680/Y681) Antibody be used to study neuronal development?

The Phospho-NTRK1 (Y680/Y681) Antibody is a valuable tool for investigating neuronal development, particularly in cholinergic systems:

• Developmental timeline analysis:

  • Track NTRK1 phosphorylation levels across different developmental stages to correlate with neuronal maturation

  • Examine region-specific activation patterns, especially in the cholinergic neurons of the basal forebrain and striatum

  • Study the paraventricular thalamic nucleus (PVT) where NTRK1 shows differential expression between anterior and posterior regions

• Neurotrophin response studies:

  • Compare NGF versus NT-3 stimulation effects on NTRK1 phosphorylation and downstream signaling

  • Investigate how NTRK1 phosphorylation relates to neuronal survival versus axonal extension functions

• Cell-type specific analysis:

  • Combine with cholinergic markers (ChAT, VAChT) to study phospho-NTRK1 specifically in cholinergic neurons

  • Examine phospho-NTRK1 in non-basal forebrain cholinergic cells to understand broader distribution patterns

• Signaling pathway cross-talk:

  • Investigate how NTRK1 phosphorylation correlates with activation of the MAPK, PI3K, and PLC-gamma pathways in developing neurons

  • Study the temporal sequence of pathway activation following NGF stimulation

• Neurodevelopmental disorder models:

  • Examine phospho-NTRK1 levels in models of congenital insensitivity to pain, anhidrosis, or cognitive disabilities associated with NTRK1 mutations

These approaches provide insights into how NTRK1 signaling contributes to neuronal development, survival, and function in normal development and pathological conditions.

What is the role of NTRK1 phosphorylation in the Hippo signaling pathway and cancer?

Recent research has revealed an unexpected crosstalk between NTRK1 signaling and the Hippo pathway, with important implications for cancer biology:

• Mechanism of crosstalk:

  • NTRK1 inhibition activates LATS1 (increases p-LATS1) and inactivates YAP (increases p-YAP)

  • Conversely, NGF stimulation decreases p-LATS1 and p-YAP levels in a time-dependent manner

  • This creates a signaling axis where NTRK1 activation leads to YAP activation through LATS1 inhibition

• Functional consequences:

  • NGF treatment upregulates YAP target genes (CTGF, CYR61, ANKRD1)

  • NTRK1 activation promotes YAP nuclear translocation, enhancing its transcriptional activity

  • This signaling promotes cancer cell proliferation and migration in an YAP-dependent manner

• Experimental validation:

  • NTRK1 knockdown increases p-LATS1 and p-YAP-S127 levels

  • NTRK1 knockdown dramatically reduces cell proliferation and migration

  • YAP inhibitor Verteporfin or siYAP reverses the growth-promoting effects of NGF

• Therapeutic implications:

  • Dual targeting of NTRK1 and YAP pathways may provide synergistic anti-cancer effects

  • NTRK1 inhibitors like AZD4547 not only block NTRK1 signaling but also impact YAP activity

  • This crosstalk provides rationale for combination therapies in cancers with activated NTRK1

The Phospho-NTRK1 (Y680/Y681) Antibody serves as a key tool for monitoring this signaling axis in cancer research, potentially leading to new therapeutic strategies targeting both pathways.

How does NTRK1 fusion status affect antibody detection and experimental design?

NTRK1 gene fusions are important oncogenic drivers in various cancers, affecting how researchers should approach experiments with Phospho-NTRK1 (Y680/Y681) Antibody:

• Fusion protein characteristics:

  • NTRK1 fusions (e.g., TPM3-NTRK1) retain the kinase domain containing Y680/Y681 phosphorylation sites

  • Fusion proteins often exhibit constitutive phosphorylation independent of ligand binding

  • Molecular weight differs from wild-type NTRK1 based on fusion partner size

• Detection considerations:

  • Adjust gel percentage to accommodate altered molecular weight of fusion proteins

  • Be aware that phosphorylation levels may be higher in fusion-positive samples even without stimulation

  • Use fusion-positive cell lines (e.g., KM12 cells with TPM3-NTRK1) as positive controls

• Inhibitor response:

  • NTRK1 fusion proteins show distinct sensitivity to inhibitors like AZD4547 or LOXO195

  • Treatment leads to dose-dependent inhibition of phosphorylation and downstream signaling

  • Complete inhibition of NTRK1 phosphorylation can be achieved at 1 μM AZD4547 in fusion-positive cells

• Downstream signaling analysis:

  • Monitor effects on multiple pathways including PLC-gamma, AKT, MEK1/2, and ERK

  • Examine expression of target genes like DUSP6, ETV1, E2F1, and CCND1

  • Consider the kinetics of pathway inhibition, which may vary between fusion and wild-type proteins

Understanding these fusion-specific considerations is essential for proper experimental design and interpretation when studying NTRK1 in cancer contexts.

What are common troubleshooting issues with Phospho-NTRK1 (Y680/Y681) Antibody and their solutions?

When working with Phospho-NTRK1 (Y680/Y681) Antibody, researchers may encounter several technical challenges. Here are common issues and their solutions:

Implementing these troubleshooting approaches will help overcome technical challenges and improve the reliability of experimental results.

How can researchers optimize Phospho-NTRK1 (Y680/Y681) Antibody for immunohistochemistry applications?

While the Phospho-NTRK1 (Y680/Y681) Antibody has been primarily validated for Western blotting and ELISA , researchers may adapt it for immunohistochemistry (IHC) with careful optimization:

• Fixation optimization:

  • Compare different fixatives (4% PFA, formalin, methanol-acetone)

  • Optimize fixation time to preserve phospho-epitopes (generally shorter is better)

  • Consider perfusion fixation for rodent tissues to improve phospho-epitope preservation

• Antigen retrieval methods:

  • Test multiple retrieval methods (heat-induced in citrate buffer pH 6.0, EDTA buffer pH 9.0, or enzymatic retrieval)

  • Compare microwave, pressure cooker, and water bath heating methods

  • Optimize retrieval time carefully as excessive retrieval may destroy phospho-epitopes

• Blocking and permeabilization:

  • Use phosphate-free blocking solutions

  • Include phosphatase inhibitors in all solutions

  • Test different permeabilization agents (0.1-0.3% Triton X-100 or 0.05-0.1% saponin)

• Antibody dilution and incubation:

  • Start with higher concentrations than used for WB (1:100-1:500)

  • Test both overnight 4°C and room temperature incubations

  • Consider signal amplification systems like tyramide signal amplification

• Controls and validation:

  • Include NTRK1 knockout tissues as negative controls

  • Compare NGF-stimulated versus unstimulated tissues

  • Validate with phosphatase treatment of sections

• Signal detection optimization:

  • Compare different detection systems (ABC, polymer-based, etc.)

  • Optimize DAB development time or fluorophore selection

  • Consider nuclear counterstaining that doesn't obscure signal

By systematically optimizing these parameters, researchers can adapt the Phospho-NTRK1 (Y680/Y681) Antibody for immunohistochemical applications to visualize NTRK1 activation in tissue contexts.