The KALRN Antibody, HRP conjugated is a diagnostic and research tool designed to detect the Kalirin protein (KALRN), a multidomain Rho GTPase-activating kinase involved in neuronal signaling, cytoskeletal regulation, and cancer-related pathways. The antibody is conjugated with horseradish peroxidase (HRP), enabling enzymatic detection in assays like ELISA, immunohistochemistry (IHC), and Western blotting.
Target: Kalirin (KALRN), a 340 kDa protein with isoforms ranging from 200–340 kDa .
Applications: ELISA, IHC, Western blotting, and immunofluorescence (IF) .
Reactivity: Primarily human, with cross-reactivity in mouse, rat, and other species depending on the product .
The antibody is typically a rabbit-derived polyclonal IgG, generated against synthetic peptides or recombinant Kalirin protein fragments . Conjugation with HRP involves covalent linkage to the antibody’s lysine residues, ensuring stability and enzymatic activity for chromogenic detection .
Buffer Requirements: Antibody buffers must avoid Tris, BSA, and sodium azide to optimize conjugation efficiency .
Stabilization: Products like LifeXtendTM extend shelf-life by mitigating HRP degradation .
KALRN mutations correlate with enhanced tumor immunogenicity and improved responses to checkpoint inhibitors (e.g., PD-1/PD-L1 therapies) . The HRP-conjugated antibody enables quantification of KALRN expression levels in tumor tissues, aiding in biomarker validation .
Kalirin regulates neuronal plasticity and cytoskeletal dynamics. The antibody is used to study its role in synaptic remodeling and neurodegenerative diseases .
Optimized for ELISA (1:500–1:1000 dilution) and IHC (1:200–400 dilution), the conjugate reduces secondary antibody steps, streamlining workflows .
Immunotherapy Biomarker: KALRN mutations predict favorable responses to immunotherapy in melanoma, lung, and endometrial cancers .
Cancer Pathogenesis: Loss-of-function mutations impair Rho GTPase signaling, enhancing tumor mutation burden (TMB) and neoantigen presentation .
Neurological Implications: Kalirin isoforms influence dendritic spine density and synaptic plasticity, linking its dysfunction to neurodevelopmental disorders .
KALRN antibodies with HRP conjugation demonstrate effectiveness across multiple applications including ELISA, immunohistochemistry (paraffin and frozen sections), and flow cytometry. When selecting applications, consider the following optimization parameters:
For ELISA: Detection limits reach approximately 1:16000 dilution
For IHC-P/IHC-F: Recommended concentration ranges from 4-5 μg/mL
For Flow Cytometry: Optimal concentration around 10 μg/mL for paraformaldehyde-fixed cells with Triton permeabilization
Each application requires specific optimization for your experimental system, with protocol adjustments based on cellular localization (primarily cytoplasmic) and expression levels in your target tissue or cell line.
To preserve antibody functionality and prevent degradation:
Store at -20°C in aliquots to avoid repeated freeze-thaw cycles
Use storage buffers containing stabilizers (typically 50% glycerol, 0.01M TBS/PBS at pH 7.4 with 1% BSA)
Include preservatives such as 0.03% Proclin300 or 0.02% sodium azide depending on formulation
Maintain cold chain during handling, keeping antibody on ice during experiments
Check expiration dates and validate activity periodically through positive controls
Long-term stability studies show minimal activity loss when properly stored, though antibody validation before critical experiments remains recommended practice.
Rigorous validation strategies include:
Western blot analysis (where applicable) to confirm detection of expected molecular weight bands
Comparison of staining patterns with other validated anti-KALRN antibodies targeting different epitopes
Testing reactivity across multiple species if conducting comparative studies (available antibodies show reactivity to human, mouse, rat, dog, pig, horse, and chicken samples)
Inclusion of negative controls (tissue sections without primary antibody) to assess background signal
Testing in cell lines with known KALRN expression levels or KALRN knockout models
Validation across multiple techniques strengthens confidence in experimental results and addresses the challenge of antibody cross-reactivity.
For optimal IHC results with KALRN antibodies:
Implement heat-induced antigen retrieval with citrate buffer (pH 6.0)
Use HRP-based detection systems for enhanced sensitivity
Titrate antibody concentrations (starting with 4-5 μg/mL recommended range)
Include appropriate blocking steps (3-5% BSA or serum)
Optimize incubation times and temperatures (typically 1 hour at room temperature or overnight at 4°C)
Apply signal amplification techniques for low-expression samples
Successful KALRN detection in human cortex tissue has been reported with these parameters, demonstrating selective neuronal localization patterns .
To differentiate wild-type from mutated KALRN:
Combine antibody-based detection with mutational analysis techniques
Quantify expression levels (KALRN expression is significantly downregulated in KALRN-mutated versus KALRN-wildtype cancers)
Implement dual staining with markers of DNA damage repair deficiency
Correlate KALRN protein detection with microsatellite instability (MSI) status
Assess co-localization with Rho GTPase family members (RAC1, RAC2, RAC3, RHOA, RHOB, RHOC, RHOD, RHOG and CDC42)
These approaches leverage the finding that KALRN mutations appear to be predominantly inactivating mutations that impair protein function .
Critical controls include:
Tissue/cell negative controls (samples known to lack KALRN expression)
No-primary-antibody controls to assess secondary antibody specificity and endogenous peroxidase activity
Isotype controls matching antibody host species and isotype (rabbit IgG for available antibodies)
Positive controls (cortical brain tissue shows reliable KALRN expression)
For flow cytometry: FMO (fluorescence minus one) controls for accurate gating strategy development
Implementing these controls enables confident interpretation of results and troubleshooting of experimental issues.
To explore this critical relationship:
Implement multiplex IHC to simultaneously detect KALRN and immune markers (CD8+ T cells, PD-L1)
Quantify KALRN expression in tumor samples stratified by response to immune checkpoint inhibitors
Compare KALRN protein levels between microsatellite instability-high (MSI-H) and microsatellite stable (MSS) tumors
Correlate KALRN expression with tumor mutation burden (TMB) metrics
Assess co-occurrence patterns between KALRN mutations and mutations in DNA damage repair pathway genes
This approach builds on research demonstrating that KALRN mutations correlate with heightened antitumor immunity, elevated PD-L1 expression, and favorable response to immunotherapies targeting PD-1/PD-L1/CTLA-4 .
To investigate KALRN's impact on DNA repair:
Analyze co-occurrence of KALRN mutations with mutations in established DNA damage repair genes (PMS1, PMS2, MLH1, MSH2, MSH3, MSH6, POLD1, POLE)
Measure DNA damage markers (γH2AX foci) in cells with modulated KALRN expression
Assess microsatellite instability status in relation to KALRN mutation status
Quantify predicted neoantigen load in KALRN-mutated versus wildtype tumors
Evaluate the functional relationship between KALRN and Rho GTPases, which play documented roles in DNA damage response regulation
This research framework addresses the mechanism by which KALRN mutations may lead to genomic instability and subsequently enhanced antitumor immunity.
Advanced image analysis approaches include:
Digital pathology algorithms to quantify KALRN staining intensity and distribution
Spatial analysis of KALRN expression relative to immune cell infiltrates
Cell-by-cell quantification of KALRN and PD-L1 co-expression
Machine learning algorithms to identify expression patterns associated with treatment response
Multiplex imaging to assess KALRN in context of key signaling pathway components
These approaches enable robust quantitative assessment of KALRN expression patterns that may be missed by qualitative evaluation alone.
Functional assessment systems include:
KALRN knockdown/overexpression models to assess impact on Rho GTPase activation
Co-culture systems with tumor and immune cells to study KALRN's influence on immune cell function
Wound healing and invasion assays to evaluate KALRN's role in cytoskeletal dynamics
GTPase activity assays (e.g., G-LISA) to measure downstream effects of KALRN modulation
Live-cell imaging approaches to monitor cytoskeletal changes following KALRN perturbation
These functional systems complement antibody-based detection approaches and provide mechanistic insights into KALRN's biological roles.
For biomarker panel development:
Combine KALRN detection with established immunotherapy biomarkers (PD-L1, TMB, MSI status)
Implement sequential immunostaining protocols that include KALRN alongside immune checkpoint molecules
Develop multiplexed flow cytometry panels incorporating KALRN with immune cell markers
Create tissue microarrays with paired pre/post-treatment samples for longitudinal assessment
Integrate with computational approaches to derive composite biomarker scores
This integrated approach may enhance predictive value beyond single biomarkers, addressing the multifactorial nature of immunotherapy response.
Key considerations for cross-disciplinary KALRN research:
Tissue-specific optimization of antibody concentrations (neuronal tissues may require different protocols)
Selection of appropriate reference genes/proteins for normalization across tissue types
Differential subcellular localization analysis (membrane-bound organelles in neurons)
Comparison of KALRN isoform expression between neural and cancer tissues
Implementation of dual staining with tissue-specific markers to contextualize expression patterns
These approaches acknowledge KALRN's diverse biological functions across tissue types, including neuronal shape regulation and vesicle trafficking versus its emerging role in cancer immunology .
Problem-solving approaches for technical challenges:
Issue | Methodological Solution |
---|---|
High background signal | Increase blocking (3-5% BSA/serum), reduce antibody concentration, lengthen washing steps |
Weak/no signal | Optimize antigen retrieval, increase antibody concentration, extend incubation time, use signal amplification |
Non-specific binding | Pre-absorb antibody, optimize blocking, use monovalent F(ab) fragments to block endogenous Fc receptors |
Inconsistent staining | Standardize fixation protocols, control incubation temperature, ensure uniform section thickness |
Signal variability between replicates | Implement automated staining platforms, prepare fresh working solutions, standardize all protocol steps |
Each solution should be systematically tested while changing only one variable at a time to identify optimal conditions for your experimental system.
Sample-specific adaptations include:
For FFPE tissues: Extended antigen retrieval (citrate buffer pH 6)
For frozen sections: Optimization of fixation protocols (paraformaldehyde concentration/duration)
For cultured cells: Permeabilization optimization (0.5% Triton recommended for flow cytometry)
For protein lysates: Buffer selection based on KALRN subcellular localization (primarily cytoplasmic)
For clinical samples: Correlation with patient data and standardization of pre-analytical variables
These adaptations account for differences in protein accessibility and preservation across sample types.