IGF1R (Ab-1346) Antibody

What is the specificity of the IGF1R (Ab-1346) Antibody?

The IGF1R (Ab-1346) Antibody specifically detects endogenous levels of IGF1 Receptor only when phosphorylated at tyrosine 1346. This antibody was generated using a synthesized non-phosphopeptide derived from human IGF1R around the phosphorylation site of tyrosine 1346 (sequence Q-P-Y(p)-A-H) . The specificity is ensured through affinity purification via sequential chromatography on phospho- and non-phospho-peptide affinity columns . This high specificity allows researchers to detect only the activated form of the receptor without cross-reactivity with the non-phosphorylated form.

What applications can the IGF1R (Ab-1346) Antibody be used for?

The IGF1R (Ab-1346) Antibody has been validated for multiple research applications:

• Western Blotting (WB): For detecting phosphorylated IGF1R in protein lysates (typical dilution 1:500-1:1000)

• Enzyme-Linked Immunosorbent Assay (ELISA): For quantitative detection

• Immunohistochemistry (IHC): For examining tissue sections (typical dilution 1:50-1:100)

• Immunofluorescence (IF): For cellular localization studies

• Immunocytochemistry (ICC): For cell-based assays

These applications make the antibody versatile for studying IGF1R signaling across different experimental setups, from protein-level detection to cellular localization studies.

What is the biological significance of the Tyr1346 phosphorylation site in IGF1R?

Tyrosine 1346 is a critical phosphorylation site in the IGF1R signaling cascade. When IGF1 or IGF2 binds to the extracellular alpha subunits of IGF1R, it induces a conformational change that leads to autophosphorylation of key tyrosine residues, including Tyr1346 . This phosphorylation event is part of the receptor activation process that initiates downstream signaling through pathways including RAS/RAF/MEK/ERK and PI3K/AKT/mTOR . These pathways regulate critical cellular processes including cell proliferation, survival, and metabolism. The phosphorylation state at Tyr1346 serves as a biomarker for receptor activation and signal transduction, making it particularly important in cancer research where IGF1R is often overexpressed or hyperactivated .

How should I optimize western blot conditions when using IGF1R (Ab-1346) Antibody?

For optimal western blot results with IGF1R (Ab-1346) Antibody:

• Sample preparation:

  • Use phosphatase inhibitors (e.g., sodium orthovanadate, sodium fluoride) in lysis buffers to preserve phosphorylation

  • Process samples quickly and keep them on ice to prevent dephosphorylation

  • Consider stimulating cells with IGF1 (50-100 ng/mL for 5-15 minutes) as a positive control

• Gel electrophoresis and transfer:

  • Use 7-8% gels to properly resolve the high molecular weight IGF1R (~95-200 kDa)

  • Ensure complete transfer of large proteins by using low SDS transfer buffer and extended transfer times

• Antibody incubation:

  • Recommended dilution: 1:500-1:1000 in 5% BSA in TBST

  • Incubate overnight at 4°C for optimal binding

  • Use TBS rather than PBS for all wash steps to prevent phosphatase activity

• Detection:

  • Use high-sensitivity ECL reagents as phospho-specific signals may be weaker than total protein

  • Consider signal enhancement systems for low abundance phosphoproteins

What are the best sample preparation methods for immunohistochemistry with IGF1R (Ab-1346) Antibody?

For effective immunohistochemistry using IGF1R (Ab-1346) Antibody:

• Tissue fixation and embedding:

  • Formalin fixation for 24-48 hours is recommended

  • Paraffin embedding should follow standard protocols

  • Fresh frozen sections can also be used but require different fixation (4% paraformaldehyde)

• Antigen retrieval:

  • Heat-induced epitope retrieval is crucial for phospho-epitopes

  • Use citrate buffer (pH 6.0) or EDTA buffer (pH 8.0)

  • Pressure cooking for 10-15 minutes provides optimal retrieval for phospho-epitopes

• Blocking and antibody incubation:

  • Block with 5-10% normal serum from the same species as the secondary antibody

  • Add 0.3% hydrogen peroxide to block endogenous peroxidase activity

  • Recommended dilution for IGF1R (Ab-1346): 1:50-1:100

  • Incubate overnight at 4°C in a humidified chamber

• Controls to include:

  • Positive control: Tissues known to express phosphorylated IGF1R (e.g., certain cancer tissues)

  • Negative control: Omit primary antibody

  • Phosphatase-treated control: Treat sections with lambda phosphatase to confirm phospho-specificity

How can I use IGF1R (Ab-1346) Antibody to study the relationship between IGF1R signaling and resistance to targeted therapies?

The IGF1R (Ab-1346) Antibody can be instrumental in studying therapy resistance mechanisms:

• Experimental design approach:

  • Establish therapy-resistant cell lines by chronic exposure to targeted agents (e.g., trastuzumab-resistant breast cancer models)

  • Compare phospho-IGF1R (Tyr1346) levels between sensitive and resistant cells using western blotting and immunofluorescence

  • Conduct time-course experiments to track changes in phosphorylation after drug exposure

• Co-immunoprecipitation studies:

  • Use IGF1R (Ab-1346) Antibody to investigate interactions between phosphorylated IGF1R and other receptor tyrosine kinases (e.g., HER2)

  • Research indicates that IGF1R physically interacts with HER2 in trastuzumab-resistant breast cancer cells but not in sensitive cells

• Pathway analysis:

  • Combine with antibodies targeting downstream components (e.g., phospho-AKT, phospho-ERK) to map pathway activation

  • Establish correlations between IGF1R phosphorylation and activation of bypass signaling mechanisms

• Therapeutic intervention studies:

  • Use the antibody to monitor changes in IGF1R phosphorylation when treating resistant cells with IGF1R inhibitors

  • Combine with other targeted therapies to evaluate synergistic effects

What are the key considerations for using IGF1R (Ab-1346) Antibody in studies involving IGF1R tyrosine kinase inhibitors?

When studying IGF1R tyrosine kinase inhibitors (TKIs), consider these methodological approaches:

• Experimental setup for inhibitor studies:

  • Establish dose-response curves using a range of inhibitor concentrations

  • Include appropriate vehicle controls

  • Determine temporal dynamics with time-course experiments (5 min to 24 hours post-treatment)

  • Use IGF1R (Ab-1346) Antibody to verify target engagement by monitoring Tyr1346 phosphorylation

• Specific TKIs to evaluate:

  • BMS-754807: A potent and reversible inhibitor of the IGF-1R/IR family kinases

  • OSI-906 (linsitinib): A dual IGF-1R/IR kinase inhibitor

  • NVP-AEW541: Specific for IGF-1R at the cellular level

• Assessing specificity and cross-reactivity:

  • Monitor IR (insulin receptor) phosphorylation to assess inhibitor specificity

  • Evaluate effects on hybrid IGF1R/IR receptors which play important roles in cancer biology

  • Use controls with selective IR inhibition to distinguish receptor-specific effects

• Resistance mechanism investigation:

  • Use the antibody to track changes in phosphorylation patterns during resistance development

  • Studies have shown that platelet-derived growth factor receptor alpha (PDGFRα) plays a role in acquired resistance to BMS-754807 in rhabdomyosarcoma

How can I differentiate between total IGF1R and phosphorylated IGF1R (pTyr1346) in my experiments?

To effectively distinguish between total and phosphorylated receptor:

• Parallel detection strategy:

  • Use a total IGF1R antibody (targeting non-phosphorylated epitopes) alongside the phospho-specific antibody

  • Calculate phosphorylation ratios (pIGF1R/total IGF1R) to normalize for expression level differences

  • Include loading controls (e.g., β-actin, GAPDH) for accurate quantification

• Sequential immunoprecipitation approach:

  • First immunoprecipitate with a total IGF1R antibody

  • Then probe with IGF1R (Ab-1346) Antibody to detect the phosphorylated fraction

  • This approach enriches the target protein before detecting its phosphorylation state

• Phosphatase treatment controls:

  • Split samples and treat one portion with lambda phosphatase

  • The phospho-signal should disappear in treated samples while total IGF1R remains detectable

  • This confirms the phospho-specificity of your antibody

• Dual immunofluorescence visualization:

  • Use different fluorophore-conjugated secondary antibodies to simultaneously detect total and phosphorylated receptor

  • This allows visualization of phosphorylation relative to total expression in the same sample

  • Co-localization analysis can provide insights into receptor activation dynamics

What are common issues when working with phospho-specific antibodies like IGF1R (Ab-1346) and how can I address them?

Phospho-specific antibodies present unique challenges:

• Weak or absent signal:

  • Ensure phosphatase inhibitors are fresh and used at appropriate concentrations

  • Verify that sample preparation maintains phosphorylation status

  • Consider using phosphatase inhibitor cocktails containing sodium orthovanadate, sodium fluoride, and β-glycerophosphate

  • Try signal amplification systems for detection

• High background:

  • Increase blocking time or concentration (5-10% BSA or normal serum)

  • Optimize antibody dilution (try 1:200-1:2000 range for western blot)

  • Increase washing steps (5-6 washes of 5-10 minutes each)

  • For IHC/IF, try using specialized blocking reagents to reduce non-specific binding

• Cross-reactivity issues:

  • The IGF1R (Ab-1346) Antibody has predicted reactivity with pig, bovine, rabbit, dog, chicken, and Xenopus proteins

  • When working with these species, include appropriate controls

  • Test peptide competition assays using the immunizing peptide to confirm specificity

• Batch-to-batch variation:

  • Always record lot numbers and validate new lots against previous ones

  • Maintain positive control samples that work consistently

  • Consider making large aliquots of validated antibody to minimize freeze-thaw cycles

How can I validate the specificity of IGF1R (Ab-1346) Antibody in my experimental system?

Thorough validation ensures reliable results:

• Positive and negative control samples:

  • Positive controls: Cell lines with known IGF1R phosphorylation (e.g., MCF-7 cells stimulated with IGF1)

  • Negative controls: IGF1R-knockout cells or cells treated with IGF1R tyrosine kinase inhibitors

  • Phosphatase-treated samples to confirm phospho-specificity

• Stimulation/inhibition experiments:

  • Stimulate cells with IGF1 (50-100 ng/mL) for 5-15 minutes to increase phosphorylation

  • Treat with specific IGF1R inhibitors like BMS-754807 or OSI-906 to decrease phosphorylation

  • Track time-dependent changes in phosphorylation after stimulation/inhibition

• siRNA knockdown validation:

  • Transfect cells with IGF1R-specific siRNA

  • The phospho-signal should decrease proportionally to the total IGF1R reduction

  • Include non-targeting siRNA controls

• Mass spectrometry correlation:

  • For ultimate validation, confirm antibody results with phospho-specific mass spectrometry

  • This can verify both the identity of the protein and the specific phosphorylation site

How can IGF1R (Ab-1346) Antibody be used to study IGF1R signaling in different cancer types?

IGF1R signaling varies across cancer types:

• Expression and phosphorylation profiling:

  • Use the antibody for tissue microarray analysis across multiple cancer types

  • Compare phosphorylation levels between tumor and adjacent normal tissues

  • Correlate with clinical outcomes to determine prognostic value

  • IGF1R is overexpressed in tumors including melanomas, colon, pancreas, prostate, and kidney cancers

• Cancer-specific signaling patterns:

  • In breast cancer: Investigate cross-talk between IGF1R and HER2/estrogen receptor

  • In colorectal cancer: Study how IGF1R phosphorylation correlates with KRAS status

  • In pediatric tumors (Ewing's sarcoma, neuroblastoma): Examine constitutive activation patterns

• Therapeutic response prediction:

  • Develop phospho-IGF1R (Tyr1346) as a biomarker for response to IGF1R-targeting therapies

  • Compare phosphorylation patterns between responders and non-responders

  • Use as a pharmacodynamic biomarker in clinical trials

• Combination therapy rationale:

  • Investigate how IGF1R phosphorylation changes with various targeted therapies

  • Studies show potential for combining IGF1R inhibitors with inhibitors of EGFR, HER2, or PDGFR

  • The antibody can help monitor pathway adaptation during combination treatments

What methodological approaches can I use to study the relationship between IGF1R and insulin receptor (IR) using the IGF1R (Ab-1346) Antibody?

IGF1R and IR share structural similarities and form hybrid receptors:

• Hybrid receptor detection strategy:

  • Immunoprecipitate with anti-IR antibody, then western blot with IGF1R (Ab-1346) Antibody

  • This approach can detect phosphorylation status of IGF1R within hybrid receptors

  • Research indicates hybrid receptors composed of IGF1R and IR isoforms have distinct binding characteristics for IGF1, IGF2, and insulin

• Isoform-specific analysis:

  • Combine with antibodies specific for IR isoform Long (IR-B) and isoform Short (IR-A)

  • Studies show hybrid receptors with different IR isoforms have different ligand preferences

  • Hybrid receptors with IR-A are more common in cancer and bind IGF2 with higher affinity

• Tissue-specific hybrid receptor profiling:

  • Hybrid receptors occur naturally in muscle, heart, kidney, adipose tissue, skeletal muscle, hepatoma, fibroblasts, spleen, and placenta

  • Compare phosphorylation patterns across these tissues to understand physiological relevance

• Cancer-specific alterations:

  • In cancer cells, the ratio of IGF1R to IR can be altered, affecting signaling outcomes

  • Use the antibody to track phosphorylation changes when manipulating receptor ratios

  • This approach helps understand how cancer cells might escape targeted therapies