irk-1 Antibody

What are IRAK1 and ASK1 antibodies and what are their primary research applications?

IRAK1 antibodies are immunological tools designed to detect and study Interleukin-1 receptor-associated kinase 1, a key mediator in the IL-1 and Toll-like receptor signaling pathways . ASK1 antibodies, such as ASK1 Antibody (F-9), specifically detect Apoptosis Signal-regulating Kinase 1 (MAP3K5) .

These antibodies have multiple research applications including:

• Western blotting (WB) for protein detection and quantification

• Immunoprecipitation (IP) for protein isolation and interaction studies

• Immunofluorescence (IF) for cellular localization studies

• Immunohistochemistry with paraffin embedded sections (IHCP) for tissue expression analysis

• Enzyme-linked immunosorbent assay (ELISA) for protein quantification in solution

When performing these techniques, researchers should carefully optimize antibody concentrations, incubation conditions, and detection methods based on the specific experimental context. For robust data, validation using appropriate positive and negative controls is essential, particularly when studying new tissue types or experimental conditions.

What are the key biological roles of IRAK1 and ASK1 in cellular signaling pathways?

IRAK1 serves as a critical component of the myddosome complex and activates the NLRP3 inflammasome, participating in multiple IL-1 and TLR-driven signaling processes that regulate immunity and inflammation . It functions downstream of Toll-like receptors and IL-1 receptors, mediating activation of NF-κB and subsequent inflammatory gene expression.

ASK1 plays a crucial role in cellular stress responses and apoptosis by activating downstream mitogen-activated protein (MAP) kinase pathways, particularly the JNK and p38 pathways . This activation mediates cellular responses to various stressors, including oxidative stress and inflammatory signals, which influence cell survival and differentiation.

Both kinases interact with numerous proteins in complex signaling networks. ASK1 interacts with proteins in the MAP kinase cascade, such as MEK-4 and MEK-3 . IRAK1 interacts with TRAF6 and other components of the myddosome complex. These interactions are critical for signal transduction and represent important targets for experimental manipulation when studying cellular responses to stress, inflammation, and pathogen recognition.

What types of IRAK1 and ASK1 antibody conjugates are available for different research applications?

For ASK1 antibodies, several conjugated forms are commercially available:

• Non-conjugated antibodies for general applications

• Agarose-conjugated antibodies (500 μg/ml, 25% agarose) for immunoprecipitation

• Horseradish peroxidase (HRP)-conjugated antibodies (200 μg/ml) for enhanced sensitivity in western blotting

• Phycoerythrin-conjugated antibodies for flow cytometry

• Fluorescein isothiocyanate (FITC)-conjugated antibodies for immunofluorescence

• Multiple Alexa Fluor® conjugates for advanced fluorescence imaging

For IRAK1 research, similar conjugated options would be available from commercial suppliers. The choice of conjugate depends on the specific research application, detection method, and experimental design. For instance, HRP conjugates provide enhanced sensitivity for western blotting without requiring secondary antibodies, while fluorescent conjugates enable direct visualization in microscopy and flow cytometry applications.

When selecting conjugated antibodies, researchers should consider factors such as signal-to-noise ratio, stability, detection equipment availability, and potential cross-reactivity issues. The specific conjugation chemistry may also affect antibody binding properties, necessitating optimization for each experimental system.

How are IRAK1 and ASK1 dysregulation implicated in specific disease pathologies?

IRAK1 dysregulation has been implicated in numerous disease pathologies through rigorous experimental studies:

Inflammatory and Autoimmune Diseases:

• Sepsis: IRAK1-deficient mice show significantly increased survival (35% mortality vs. 85% in wild-type) in polymicrobial sepsis models, with reduced plasma IL-6 and IL-10 levels. The IRAK1-1595T haplotype in patients is associated with increased neutrophil NF-κB activation, higher risk of shock (OR 2.9, P=0.047), prolonged mechanical ventilation (OR 2.7, P=0.04), and higher 60-day mortality (OR 2.7, P=0.05) .

• Systemic Lupus Erythematosus (SLE): Multiple IRAK1 SNPs show association with increased SLE risk (OR>1.5), with the rs1059702 SNP specifically linked to SLE susceptibility (OR 1.43). IRAK1 deficiency abrogated lupus-associated phenotypes in congenic mouse models, demonstrating a causal relationship .

• Liver Fibrosis: In the STAM mouse model, pacritinib (an IRAK1 inhibitor) significantly reduced liver fibrotic area (P<0.01) and CK-18 fragment levels (P<0.05), indicating potential therapeutic applications .

Metabolic Disorders:

• Type 2 Diabetes: IRAK1 knockout mice exhibit improved glucose tolerance and insulin-stimulated glucose disposal rates. In T2D patients, IRAK1 mRNA expression is increased (P=0.028) while miRNA-146a, which inhibits IRAK1, is decreased in both PBMCs (P=0.004) and plasma (P=0.008) .

• Obesity: IRAK1 gene expression is significantly higher in adipose tissue from obese versus non-obese individuals (P=0.01) and correlates with TNFα mRNA levels .

ASK1 dysregulation has been linked to:

• Cancer: Aberrant ASK1 signaling contributes to cancer progression through effects on apoptosis and cell survival pathways .

• Neurodegenerative disorders: Altered ASK1 activation is implicated in neuronal cell death mechanisms relevant to neurodegenerative conditions .

These findings highlight the potential of targeting IRAK1 and ASK1 in therapeutic development for a range of inflammatory, autoimmune, metabolic, and neoplastic diseases.

What are the current experimental approaches for studying IRAK1 and ASK1 inhibition in disease models?

Researchers employ diverse experimental approaches to study IRAK1 and ASK1 inhibition:

Genetic Approaches:

• Knockout models: IRAK1 knockout mice have been used to assess physiological functions in various disease contexts, including sepsis, where they showed significantly reduced mortality compared to wild-type mice .

• Knock-in models: Animals engineered with inactive IRAK1 mutations (e.g., IRAK1[D359A]-knock-in mice) help distinguish between kinase-dependent and scaffold functions .

• Genetic polymorphism studies: Analysis of naturally occurring polymorphisms, such as the IRAK1-1595T haplotype associated with sepsis outcomes .

RNA-Based Methods:

• Short hairpin RNA (shRNA): Used for stable IRAK1 knockdown in cell lines and animal models .

• MicroRNA studies: Particularly focusing on miR-146a, an endogenous repressor of IRAK1. MiR-146a knockout mice show hypersensitivity to LPS challenge .

• Small interfering RNA (siRNA): Employed for transient IRAK1 knockdown in cellular experiments .

Pharmacological Inhibition:

• IRAK1/4 inhibitor I: A non-selective inhibitor used in preclinical studies that reduced mortality, neurological deficits, and ischemic infarct volume in rat models of middle cerebral artery occlusion .

• Pacritinib: A JAK2/FLT3 inhibitor that also inhibits IRAK1 at clinically relevant concentrations (IC50 6 nM). In clinical trials, pacritinib demonstrated effects on inflammatory conditions and shows promise for treating myelofibrosis .

Disease Models Used:

• Inflammatory models: Cecal ligation and puncture (CLP), lipopolysaccharide (LPS) challenge for sepsis; liver ischemia/reperfusion models

• Autoimmune models: SLE models like B6.Sle1.IRAK-/y and B6.Sle3.IRAK-/y mice

• Metabolic disease models: Streptozotocin-induced diabetic rats, diabetic peripheral neuropathy models

• Fibrosis models: STAM mouse model for liver fibrosis

The integration of these complementary approaches provides comprehensive insights into the roles of these kinases in disease pathogenesis and their potential as therapeutic targets.

How do researchers differentiate between IRAK1 kinase activity and scaffold functions in experimental designs?

Differentiating between IRAK1's enzymatic activity and its scaffold functions requires sophisticated experimental designs:

Kinase-Dead Mutants:
The most definitive approach involves using kinase-dead IRAK1 mutants. For example, studies have utilized IRAK1[D359A]-knock-in mice, which express catalytically inactive IRAK1 that retains structural integrity and protein interaction capabilities . By crossing these mice with ABIN1 mice (which develop lupus-like phenotypes), researchers demonstrated that IRAK1 kinase activity, not just its scaffold function, was necessary for the development of autoimmunity, splenomegaly, and tissue inflammation .

Comparative Pharmacological Studies:
Researchers can compare the effects of selective IRAK1 kinase inhibitors to those of genetic knockouts. When a phenotype is rescued by a kinase inhibitor and similarly by a kinase-dead mutant, but not by complete protein removal, it suggests the phenotype depends specifically on IRAK1's catalytic activity rather than its scaffold functions.

Structure-Function Analysis:
Domain-specific mutations or deletions help identify which regions of IRAK1 are essential for specific functions. This approach helps map kinase-dependent versus scaffold-dependent roles by selectively disrupting functional domains while preserving others.

Downstream Signaling Analysis:
Using phosphorylation-specific antibodies to measure activation of downstream targets helps determine which outcomes depend on IRAK1's catalytic activity. For example, monitoring NF-κB phosphorylation in PBMCs from SLE patients revealed that IRAK1/4 inhibition reduced this phosphorylation, indicating a kinase-dependent effect .

Temporal Signaling Studies:
Time-course experiments can help distinguish between immediate kinase-dependent effects and delayed scaffold-dependent effects, as these may operate on different time scales.

These methodological approaches are crucial for developing targeted therapeutic strategies that might selectively inhibit disease-associated kinase functions while preserving beneficial scaffold functions, potentially reducing side effects.

What are the considerations when interpreting results from IRAK1 and ASK1 studies across different tissue contexts?

When interpreting results from IRAK1 and ASK1 studies across different tissue contexts, several critical factors must be considered:

Tissue-Specific Expression Patterns:

Pathway Cross-talk and Redundancy:

• The impact of IRAK1 or ASK1 inhibition differs between tissues due to varying levels of complementary or redundant signaling pathways.

• IRAK1 knockout mice showed improved insulin-stimulated glucose uptake specifically in muscle but not in liver tissue, highlighting tissue-specific effects .

• Alternative signaling mechanisms may compensate for IRAK1/ASK1 inhibition in certain tissues but not others.

Microenvironmental Factors:

• Tissue-specific microenvironmental conditions significantly alter consequences of IRAK1/ASK1 modulation.

• In ischemia/reperfusion models, tissue-specific outcomes were observed: IRAK1 deficiency protected against intestinal damage, while miRNA-146a transfection reduced cardiac infarct size by 50% .

• Oxygen tension, pH, metabolic state, and resident immune cell populations contribute to these tissue-specific responses.

Disease Context Variations:

• The same molecular intervention produces different outcomes depending on disease context and affected tissue.

• In metabolic disease studies, IRAK1 modulation effects differed between high-fat and low-fat diet conditions .

• Acute versus chronic disease states may show different dependencies on IRAK1/ASK1 signaling.

Cell Type Heterogeneity Within Tissues:

• Tissues contain multiple cell types with potentially different roles for IRAK1/ASK1 signaling.

• Effects observed at the whole-tissue level may mask opposing responses in different cellular subpopulations.

• Single-cell approaches may be necessary to fully understand tissue-specific mechanisms.

What are the optimal protocols for using IRAK1 and ASK1 antibodies in Western blotting and immunoprecipitation?

Western Blotting Protocol for ASK1 and IRAK1 Antibodies:

• Sample Preparation:

  • Extract proteins from cells or tissues using an appropriate lysis buffer containing protease and phosphatase inhibitors

  • Quantify protein concentration using Bradford or BCA assay

  • Prepare samples with 20-50 μg total protein per lane in Laemmli buffer containing 2-mercaptoethanol

  • Heat samples at 95°C for 5 minutes to denature proteins

• Gel Electrophoresis and Transfer:

  • Separate proteins using SDS-PAGE (8-10% gels recommended for these high molecular weight kinases)

  • Transfer proteins to PVDF or nitrocellulose membrane at 100V for 1-2 hours or 30V overnight at 4°C

  • Verify transfer efficiency using Ponceau S staining

• Antibody Incubation:

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

  • For ASK1 detection, dilute ASK1 Antibody (F-9) to working concentration (1:500-1:1000) in blocking solution

  • For IRAK1 detection, use validated IRAK1 antibodies at manufacturer-recommended dilutions

  • Incubate with primary antibody overnight at 4°C with gentle rocking

  • Wash 3x with TBST, 5 minutes each

  • Incubate with appropriate HRP-conjugated secondary antibody (or use direct HRP-conjugated primary antibodies if available) for 1 hour at room temperature

  • Wash 4x with TBST, 10 minutes each

• Detection and Analysis:

  • Apply ECL substrate and detect signal using film or digital imaging system

  • For quantification, normalize to appropriate loading controls (β-actin, GAPDH)

  • Perform densitometric analysis using appropriate software (ImageJ, etc.)

Immunoprecipitation Protocol:

• Lysate Preparation:

  • Prepare cell/tissue lysate in non-denaturing IP buffer containing protease/phosphatase inhibitors

  • Pre-clear lysate with protein A/G beads for 1 hour at 4°C to reduce non-specific binding

  • Reserve a small aliquot of pre-cleared lysate as input control

• Antibody Binding:

  • For ASK1 IP, use agarose-conjugated ASK1 Antibody (F-9) AC (500 μg/ml, 25% agarose)

  • For IRAK1 IP, incubate 1-5 μg of IRAK1 antibody with 500-1000 μg of protein lysate overnight at 4°C

  • For non-conjugated antibodies, add protein A/G beads and incubate for an additional 2-4 hours

  • Include isotype control antibodies in parallel samples to assess non-specific binding

• Washing and Elution:

  • Wash immunoprecipitates 4-5 times with IP buffer

  • Elute proteins by boiling in SDS sample buffer for 5 minutes

  • Analyze by Western blotting as described above, comparing to input control

These protocols should be optimized for specific experimental conditions. For phosphorylation studies, phosphatase inhibitors are critical, and phospho-specific antibodies may require BSA rather than milk for blocking to prevent non-specific dephosphorylation.

How can researchers effectively use IRAK1 and ASK1 antibodies to study their roles in inflammatory disease models?

Researchers can effectively use IRAK1 and ASK1 antibodies to study inflammatory disease models through several methodological approaches:

Tissue Expression Analysis:

• Use immunohistochemistry with paraffin-embedded sections (IHCP) to analyze expression patterns in diseased versus healthy tissues .

• Quantify expression levels using Western blotting and normalize to housekeeping proteins.

• For sepsis, liver fibrosis, or SLE models, compare expression across disease progression stages to identify temporal changes in signaling pathways.

• Section thickness, antigen retrieval methods, and antibody concentration must be optimized for each tissue type.

Activation State Assessment:

• Use phospho-specific antibodies to detect activated forms of IRAK1 and ASK1.

• Monitor IRAK1 phosphorylation in experimental models before and after interventions, as demonstrated in AML cells where pacritinib inhibited constitutively activated IRAK1 phosphorylation .

• Include appropriate controls for phosphorylation status, including dephosphorylated samples.

Signaling Pathway Analysis:

• Use co-immunoprecipitation with ASK1 or IRAK1 antibodies to identify interaction partners in disease states.

• Investigate downstream signaling by measuring phosphorylation of targets like NF-κB, JNK, and p38 MAPK.

• In sepsis models, IRAK1 T haplotype was associated with greater NF-κB nuclear translocation upon LPS stimulation, providing a measurable readout of pathway activation .

Cellular Localization Studies:

• Use immunofluorescence with ASK1 or IRAK1 antibodies to track protein localization during inflammatory responses .

• Combine with markers for cellular compartments or co-stain with interaction partners.

• Use confocal microscopy for precise localization and colocalization analysis.

In Vivo Disease Model Applications:

• For sepsis models (CLP or LPS challenge), track IRAK1 expression in neutrophils and correlate with inflammatory cytokine production .

• In liver fibrosis models, examine IRAK1 levels in hepatic stellate cells in relation to disease progression and fibrotic area .

• For autoimmune conditions like SLE, analyze IRAK1 expression in immune cell subsets from affected tissues and correlate with disease parameters.

Integration with Functional Studies:

• Combine antibody-based detection with functional readouts such as cytokine production, immune cell migration, or tissue damage markers.

• For example, in the STAM mouse model, correlate IRAK1 inhibition by pacritinib with reduced liver fibrotic area (P<0.01) and CK-18 fragment levels (P<0.05) .

These methodological approaches, when systematically applied, generate comprehensive insights into the roles of IRAK1 and ASK1 in inflammatory disease pathogenesis and therapeutic targeting.

What are the critical controls and validation steps needed when using IRAK1 and ASK1 antibodies in research?

When using IRAK1 and ASK1 antibodies in research, implementing proper controls and validation steps is essential for generating reliable and reproducible results:

Antibody Validation Controls:

• Positive Controls:

  • Cell lines or tissues known to express high levels of the target protein

  • For IRAK1, PBMCs from SLE patients have been shown to overexpress IRAK1 and could serve as positive controls

  • For ASK1, select appropriate positive controls based on known expression patterns in relevant tissues

• Negative Controls:

  • Knockout cell lines or tissues (IRAK1-/- or ASK1-/- samples)

  • Samples where the target protein has been depleted through siRNA or shRNA

  • IRAK1 knockout mice tissues provide excellent negative controls for antibody validation

  • Include secondary antibody-only controls to assess non-specific binding

• Peptide Competition Assays:

  • Pre-incubate antibody with excess target peptide before application to samples

  • Signal should be significantly reduced or eliminated if the antibody is specific

  • Use titrated amounts of blocking peptide to demonstrate dose-dependent inhibition

• Multiple Antibody Validation:

  • Use multiple antibodies targeting different epitopes of the same protein

  • Consistent results across different antibodies increase confidence in specificity

  • Compare monoclonal and polyclonal antibodies to confirm target recognition

Experimental Controls:

• Loading Controls:

  • Include appropriate loading controls (β-actin, GAPDH) for Western blots

  • For immunohistochemistry, include internal control tissues or cell types on the same slide

  • Quantify and normalize target protein levels to loading controls for accurate comparisons

• Isotype Controls:

  • Include appropriate isotype-matched control antibodies to assess non-specific binding

  • For ASK1 Antibody (F-9), which is a mouse monoclonal IgG1 kappa light chain antibody, use matched isotype controls

  • Apply identical concentrations and conditions as the primary antibody

• Technical Replicates:

  • Perform experiments with at least three technical replicates to ensure reproducibility

  • The search results show statistical analysis across multiple experimental replicates (e.g., P<0.01 for liver fibrotic area reduction)

  • Include biological replicates to account for natural variation

Validation of Functional Studies:

Adherence to these critical controls and validation steps ensures research findings based on IRAK1 and ASK1 antibodies are reliable, specific, and reproducible across different laboratories and experimental settings.

What experimental design should be used to study the interplay between IRAK1/ASK1 and microRNA-146a in disease models?

An effective experimental design to study the interplay between IRAK1/ASK1 and microRNA-146a in disease models requires a multi-faceted approach:

1. Expression Correlation Studies:

• Tissue/Cell Analysis:

  • Measure miR-146a, IRAK1, and ASK1 expression levels across disease progression using qRT-PCR and Western blotting

  • Example from search results: miR-146a expression levels were decreased in PBMCs (P=0.004) and plasma (P=0.008) of T2D patients versus controls, while IRAK1 mRNA expression was increased (P=0.028)

  • Perform correlation analysis between miR-146a levels and IRAK1/ASK1 expression to establish relationship strength

  • Use in situ hybridization for miR-146a combined with immunohistochemistry for IRAK1/ASK1 to assess co-localization

• In Vivo Disease Monitoring:

  • Track temporal changes in miR-146a and IRAK1/ASK1 levels during disease progression

  • Example: In liver I/R mouse models, miR-146a decreased while IRAK1 increased in Kupffer cells after I/R

  • Collect samples at multiple timepoints to establish causality rather than mere correlation

2. Mechanistic Investigation:

• miR-146a Overexpression Studies:

  • Transfect cells/tissues with miR-146a mimics using appropriate delivery systems

  • Measure resulting changes in IRAK1/ASK1 expression and activation

  • Assess downstream functional outcomes such as inflammatory cytokine production

  • Example: miR-146a transfection suppressed IRAK1 and TRAF6 expression, decreased infarct size by 50%, and attenuated apoptosis in myocardial I/R models

• miR-146a Inhibition Studies:

  • Use antagomirs to inhibit endogenous miR-146a

  • Measure effects on IRAK1/ASK1 expression and related pathways

  • Example: miR-146a knockout mice were hypersensitive to LPS challenge, demonstrating enhanced inflammatory responses

  • Include appropriate controls for transfection efficiency and off-target effects

3. Disease-Specific Models:

• Inflammatory Disease Models:

  • Use relevant models such as:

    • Sepsis: CLP or LPS challenge models with varying severity

    • Autoimmunity: SLE mouse models (B6.Sle1.IRAK-/y and B6.Sle3.IRAK-/y)

    • Metabolic disorders: Diabetic models with miR-146a modulation

  • Example: In STZ rats vs. DPN rats, miR-146a expression decreased in diabetic peripheral neuropathy, with corresponding increases in inflammatory markers (TNFα, IL-1β, NF-κB)

  • Measure disease-specific parameters alongside molecular markers

• Tissue-Specific Effects:

  • Compare miR-146a/IRAK1/ASK1 interplay across different tissues in the same disease model

  • Example: IRAK1 knockout mice showed tissue-specific effects in glucose metabolism between muscle and liver tissues

  • Use tissue-specific promoters for targeted miR-146a modulation

4. Therapeutic Intervention Studies:

• miR-146a Restoration Therapy:

  • Deliver miR-146a mimics in disease models and monitor:

    • IRAK1/ASK1 expression changes

    • Disease parameter improvements

  • Example: Lentivirus-expressing miR-146a delivered into myocardium reduced IRAK1 expression and protected against cardiac dysfunction in sepsis models

  • Test different delivery methods and dosing schedules

This comprehensive experimental design enables thorough characterization of the miR-146a/IRAK1/ASK1 regulatory axis in disease contexts and assessment of its therapeutic potential.