far-2 Antibody

What is FAR2 and what is its biological function?

FAR2 (fatty acyl-CoA reductase 2) is a peroxisome-localized enzyme that catalyzes the reduction of saturated C16 or C18 fatty acyl-CoA to fatty alcohols, but notably does not process unsaturated fatty acids . In humans, the canonical FAR2 protein consists of 515 amino acid residues with a molecular mass of approximately 59.4 kDa, and up to two different isoforms have been reported . FAR2 belongs to the fatty acyl-CoA reductase protein family and is widely expressed across various tissue types. The protein plays critical roles in lipid metabolism pathways and has been implicated in several disease processes, particularly kidney disorders .

FAR2 is also known by several synonyms: male sterility domain-containing protein 1 (MLSTD1), short chain dehydrogenase/reductase family 10E member 2, and epididymis secretory protein Li 81 . Evolutionary conservation of this protein is evident from its orthologs in multiple species including mouse, rat, bovine, chimpanzee, and chicken .

What applications are FAR2 antibodies typically used for?

FAR2 antibodies are employed in a diverse range of immunological applications in research settings. The most common applications include:

• Immunohistochemistry (IHC): For detecting FAR2 protein in tissue sections, including paraffin-embedded specimens. This is particularly valuable for examining FAR2 distribution in kidney tissues when studying associated pathologies .

• Western Blot (WB): For confirming the presence and quantity of FAR2 protein in tissue or cell lysates. This technique allows researchers to verify protein size and estimate relative abundance .

• Enzyme-Linked Immunosorbent Assay (ELISA): For quantitative detection of FAR2 protein in solution .

• Immunocytochemistry (ICC) and Immunofluorescence (IF): For visualizing the subcellular localization of FAR2 in cultured cells, confirming its peroxisomal location .

Optimal methodological approaches vary by application, with recommended dilutions typically ranging from 1:500-1:2000 for Western blot and 1:50-1:200 for immunohistochemistry applications .

How should FAR2 antibodies be stored and handled to maintain optimal activity?

To preserve antibody functionality and specificity, proper storage and handling of FAR2 antibodies is essential. Most commercial FAR2 antibodies require storage at -20°C . The antibodies are commonly supplied in one of two forms:

• Liquid formulation: Often provided in PBS buffer (pH 7.3) containing stabilizers such as 50% glycerol and preservatives like 0.05% sodium azide (NaN₃) .

• Lyophilized (freeze-dried) form: Requires reconstitution before use, typically in 100 μl of sterile distilled water with 50% glycerol .

For optimal preservation:

• Avoid repeated freeze-thaw cycles as they can degrade antibody quality and reduce binding efficiency

• Aliquot reconstituted antibodies into single-use volumes before freezing

• Allow antibodies to equilibrate to room temperature before opening to prevent condensation

• Follow manufacturer-specific recommendations for reconstitution volumes and buffer compositions

Working dilutions should be prepared fresh and used within 24 hours for maximum sensitivity and reproducibility in experimental applications.

What are the key considerations for validating FAR2 antibody specificity in experimental systems?

Validating antibody specificity is crucial for generating reliable research data. For FAR2 antibodies, a comprehensive validation approach should include:

• Multiple detection methods validation: Compare results across Western blot, immunohistochemistry, and immunofluorescence to confirm consistent targeting patterns. Observed molecular weight should align with the expected 59 kDa for human FAR2 .

• Peptide competition assays: Pre-incubate the antibody with excess immunizing peptide before application to verify that signal elimination occurs when the antibody binding sites are occupied.

• Knockout/knockdown controls: Use tissue or cells from FAR2 knockout models (such as Far2 tm2a(KOMP)Wtsi/2J mice) as negative controls . Alternatively, employ siRNA knockdown in cell lines to create controlled systems with reduced FAR2 expression.

• Cross-reactivity assessment: When working with antibodies that claim cross-reactivity with multiple species (human, mouse, rat), confirm specificity in each species separately, as epitope conservation may vary .

• Batch-to-batch consistency testing: When obtaining new lots of the same antibody, perform parallel validation with previous lots to ensure consistent performance.

For immunohistochemical applications specifically, recommended controls include thyroid cancer tissue, which has demonstrated reliable FAR2 detection at a 1:50 dilution .

How can FAR2 antibodies be optimized for detecting different isoforms or post-translational modifications?

Optimizing FAR2 antibody protocols for detecting specific isoforms or post-translational modifications requires strategic approaches:

• Isoform-specific detection: With two reported FAR2 isoforms , selection of antibodies raised against isoform-specific epitopes is critical. Examine the immunogen sequence details from manufacturers to determine which protein regions are targeted. Antibodies generated against internal residues of human FAR2 may detect both isoforms, while those targeting unique regions can provide isoform specificity.

• Electrophoretic separation optimization: For Western blot applications, use lower percentage SDS-PAGE gels (6%) to improve separation of closely migrating isoforms, as demonstrated in human fetal liver tissue analyses .

• Post-translational modification detection:

  • Use phospho-specific antibodies when investigating regulatory phosphorylation events

  • Adjust lysis buffer composition to preserve modifications of interest (e.g., include phosphatase inhibitors for phosphorylation studies)

  • Consider native gel electrophoresis when protein complexes or conformational epitopes are important

• Sample preparation considerations: Extract protocols should be tailored to subcellular localization; since FAR2 is peroxisomal, ensure extraction methods effectively solubilize peroxisomal membranes while preserving epitope integrity.

• Signal amplification techniques: For low-abundance modifications, employ tyramide signal amplification or higher sensitivity detection systems with extended primary antibody incubation periods (overnight at 4°C).

What methodologies are recommended for investigating FAR2's role in kidney disease pathogenesis?

Based on emerging evidence linking FAR2 to kidney diseases , researchers should consider these methodological approaches:

• Animal model selection and development:

  • Utilize Far2 knockdown mice models, which have demonstrated delayed progression of mesangial matrix expansion

  • Consider kidney-specific conditional knockout systems to isolate renal effects from systemic consequences

  • Age-matched controls are essential as kidney pathology develops over time

• Human tissue analysis protocols:

  • Implement multi-parameter immunohistochemistry to co-localize FAR2 with disease markers in clinical specimens

  • Standardize tissue processing to enable comparison between diabetic nephropathy, lupus nephritis, and IgA nephropathy samples

  • Establish quantitative scoring systems for FAR2 expression levels relative to disease progression

• Mechanistic investigation techniques:

  • Employ cell-based assays to measure platelet-activating factor synthesis in response to FAR2 manipulation, as FAR2 mediates de novo synthesis of this factor

  • Investigate NKX3.2 transcription factor activity, which drives Far2 expression

  • Utilize metabolomic approaches to track changes in fatty alcohol production

• Multi-omics integration strategy:

  • Correlate FAR2 protein levels with transcriptomic profiles in kidney disease

  • Map FAR2-dependent metabolite changes with proteomic alterations in disease models

  • Track lipid composition changes in affected tissues

• Therapeutic intervention assessment:

  • Design approaches to modulate FAR2 activity pharmacologically

  • Monitor mesangial matrix expansion as a key endpoint using standardized histological techniques

  • Establish biochemical markers that reflect FAR2 activity in accessible biofluids

What analytical considerations are important when quantifying FAR2 expression levels in comparative studies?

Robust quantification of FAR2 expression requires careful analytical attention to several factors:

• Reference gene selection for normalization:

  • Use multiple reference genes with demonstrated stability across experimental conditions

  • Verify reference gene suitability separately for each tissue type under investigation

  • For qPCR analysis of Far2, design primers that span exon junctions (e.g., between exons 9 and 10 as used in published research)

• Standardization protocols for Western blot quantification:

  • Implement loading controls appropriate for the subcellular fraction (peroxisomal)

  • Use standard curves with recombinant FAR2 protein for absolute quantification

  • Apply densitometry methods that account for non-linear signal response

• Antibody dilution optimization:

  • Establish optimal working dilutions empirically for each application (1:1000 for Western blot, 1:50 for IHC have been validated)

  • Perform dilution series to ensure detection within the linear range

  • Standardize exposure times for imaging-based quantification

• Statistical approach for comparative analyses:

  • Account for biological variability with appropriate sample sizes

  • Apply suitable statistical tests based on data distribution

  • Consider power calculations to determine minimum detectable differences

• Cross-platform validation:

  • Correlate protein levels (Western blot/IHC) with mRNA expression (qPCR)

  • Verify subcellular localization with fractionation and immunofluorescence

  • Compare results across multiple antibody clones when available

How should experiments be designed to investigate FAR2's involvement in lipid metabolism pathways?

Investigating FAR2's role in lipid metabolism requires carefully designed experimental approaches:

• Cellular model selection:

  • Choose cell types with endogenous FAR2 expression or controlled overexpression systems

  • Include both standard cell lines and primary cells derived from tissues with known FAR2 function

  • Consider peroxisome-enriched cell types such as hepatocytes and renal cells

• Experimental intervention design:

  • Implement CRISPR/Cas9-mediated FAR2 knockout or siRNA knockdown approaches

  • Develop point mutations affecting catalytic activity to distinguish enzymatic from structural roles

  • Create inducible expression systems for temporal control of FAR2 levels

• Substrate specificity characterization:

  • Supply radiolabeled fatty acyl-CoA substrates of varying chain lengths (C16-C18) and saturation

  • Measure conversion to fatty alcohols using thin-layer chromatography or LC-MS

  • Compare processing of saturated versus unsaturated fatty acids to confirm substrate preferences

• Metabolic pathway analysis:

  • Track metabolic flux through FAR2-dependent pathways using stable isotope labeling

  • Measure changes in downstream products such as wax esters and ether lipids

  • Investigate potential regulatory feedback mechanisms affecting FAR2 activity

• Interaction mapping:

  • Identify protein-protein interactions using co-immunoprecipitation with FAR2 antibodies

  • Determine co-localization with other peroxisomal enzymes

  • Assess whether FAR2 functions in multi-enzyme complexes or independently

What control samples should be included when using FAR2 antibodies in different experimental applications?

Robust experimental design with appropriate controls is essential for antibody-based research:

Additional considerations for control samples:

• Cross-reactivity controls: When testing antibodies with claimed multi-species reactivity, include samples from each species to verify specificity .

• Expression level controls: Include samples with known high, medium, and low expression levels of FAR2 to demonstrate detection sensitivity range.

• Isoform controls: Where possible, include systems expressing specific FAR2 isoforms to verify detection capabilities.

• Environmental variable controls: Account for factors that might affect FAR2 expression, such as cellular stress conditions or treatment durations.

• Batch effect controls: Include reference samples across different experimental runs to normalize for inter-assay variability.

How can researchers optimize immunohistochemical protocols for FAR2 detection in different tissue types?

Optimizing immunohistochemical FAR2 detection requires tissue-specific considerations:

• Tissue fixation and processing optimization:

  • For formalin-fixed paraffin-embedded (FFPE) tissues, limit fixation time to 24 hours

  • Consider alternative fixatives for tissues where standard formalin fixation masks FAR2 epitopes

  • Use freshly cut sections (4-6μm) and process within 1-2 weeks for optimal antigen preservation

• Antigen retrieval method selection:

  • Test multiple antigen retrieval approaches (heat-induced vs. enzymatic)

  • Optimize pH conditions (citrate buffer pH 6.0 vs. EDTA buffer pH 9.0)

  • Adjust retrieval duration based on tissue type (typically 15-30 minutes)

• Antibody incubation parameters:

  • Test dilution ranges (1:50-1:200 recommended for IHC)

  • Compare overnight incubation at 4°C versus shorter incubations at room temperature

  • Evaluate blocking reagents to minimize background signal

• Detection system considerations:

  • Select chromogenic versus fluorescent detection based on research needs

  • For low-abundance detection, implement signal amplification methods (HRP-polymer, tyramide)

  • Consider multiplexing with other markers to provide contextual information

• Tissue-specific protocol adjustments:

  • For kidney tissue: Special attention to glomerular architecture preservation

  • For liver tissue: Additional blocking steps to reduce endogenous biotin or peroxidase

  • For brain tissue: Extended penetration times for antibodies

• Validation approaches:

  • Include positive control tissues with known FAR2 expression (thyroid cancer tissue has been validated)

  • Implement peptide competition controls

  • Compare staining patterns with multiple anti-FAR2 antibodies targeting different epitopes

How should unexpected results with FAR2 antibodies be investigated and resolved?

When facing unexpected results with FAR2 antibodies, a systematic troubleshooting approach is recommended:

• Multiple band patterns in Western blot:

  • Verify if additional bands represent isoforms, post-translational modifications, or degradation products

  • Adjust sample preparation to minimize proteolysis (add protease inhibitors, maintain cold conditions)

  • Test antibody specificity with peptide competition assays

  • Compare results with antibodies targeting different epitopes of FAR2

• Weak or absent signal:

  • Verify FAR2 expression in the chosen sample through alternate methods (qPCR)

  • Optimize protein extraction for peroxisomal proteins using specialized lysis buffers

  • Increase antibody concentration or extend incubation periods

  • For Western blot, load greater amounts of protein (40μg has been validated)

  • Evaluate if sample processing has compromised epitope integrity

• Unexpected cellular localization:

  • Confirm peroxisomal markers co-localize with FAR2 signal

  • Evaluate fixation effects on apparent localization

  • Consider cell-type specific differences in FAR2 trafficking

  • Verify antibody specificity with genetic knockdown controls

• Inconsistent results between applications:

  • Recognize that epitope accessibility differs between applications (native vs. denatured conditions)

  • Optimize protocols specifically for each application rather than using universal conditions

  • Consider using application-specific antibodies (some antibodies perform better in WB than IHC)

• Cross-reactivity concerns:

  • Evaluate sequence homology between FAR2 and related proteins (especially FAR1)

  • Include knockout/knockdown controls to confirm specificity

  • Test in multiple species if using antibodies with claimed cross-reactivity

What factors might lead to conflicting data when studying FAR2 expression in disease models?

Several factors can contribute to conflicting results when investigating FAR2 in disease contexts:

• Disease stage heterogeneity:

  • FAR2 expression may fluctuate throughout disease progression

  • Standardize sampling timepoints in animal models

  • Document clinical stage carefully in human samples

  • Consider temporal expression analyses rather than single-point measurements

• Cell type-specific expression patterns:

  • FAR2 expression may vary between cell types within the same tissue

  • Implement single-cell approaches or cell sorting before analysis

  • Use co-localization with cell-type specific markers to identify expressing populations

  • Consider spatial transcriptomics to map expression distribution

• Methodology-dependent outcomes:

  • Protein levels may not correlate with mRNA expression

  • Different antibodies may detect distinct subpopulations of FAR2

  • Variations in sample processing can affect epitope preservation

  • Standardize protocols across comparative studies

• Genetic background effects:

  • FAR2's association with kidney disease varies between mouse strains

  • Document complete genetic background information

  • Control for 9-bp sequence variation in the 5′-UTR region of Far2 in mouse studies

  • Consider using congenic lines to isolate genetic contributions

• Environmental and physiological factors:

  • Metabolic state can influence lipid metabolism pathways

  • Control for factors like diet, age, and hormonal status

  • Document housing conditions for animal models

  • Consider circadian influences on FAR2 expression

How can researchers integrate FAR2 antibody data with other experimental approaches to strengthen research findings?

• Multi-level expression analysis:

  • Correlate protein detection (antibody-based) with mRNA expression (qPCR, RNA-seq)

  • Verify if transcriptional regulation by NKX3.2 correlates with protein abundance

  • Consider epigenetic regulation through ChIP-seq or methylation analysis

  • Employ ribosome profiling to assess translational efficiency

• Functional validation approaches:

  • Combine expression data with enzymatic activity assays

  • Measure downstream metabolites (fatty alcohols) to confirm functional consequences

  • Assess platelet-activating factor synthesis in relation to FAR2 levels

  • Implement rescue experiments in knockout/knockdown systems

• Spatial-temporal integration:

  • Correlate immunohistochemical localization with tissue-specific metabolomics

  • Track expression changes over disease progression timepoints

  • Map FAR2 distribution relative to pathological features

  • Implement lineage tracing in development studies

• Cross-species validation:

  • Compare findings between mouse models and human patients

  • Verify conservation of regulatory mechanisms across species

  • Consider evolutionary aspects of FAR2 function in orthologs

• Clinical correlation strategies:

  • Associate FAR2 expression patterns with disease outcomes

  • Correlate with established biomarkers of kidney function

  • Stratify patient populations based on FAR2 expression profiles

  • Consider pharmacological modulation of FAR2 as therapeutic strategy

What emerging technologies might enhance FAR2 antibody applications in research?

Emerging technologies offer new opportunities for advancing FAR2 research:

• Advanced imaging approaches:

  • Super-resolution microscopy for precise subcellular localization within peroxisomes

  • Live-cell imaging with FAR2 antibody fragments to track dynamics

  • Expansion microscopy for enhanced spatial resolution of peroxisomal networks

  • Correlative light and electron microscopy to link molecular detection with ultrastructure

• Antibody engineering innovations:

  • Development of single-domain antibodies (nanobodies) for improved penetration

  • Site-specific conjugation strategies for oriented immobilization

  • Bispecific antibodies targeting FAR2 and interaction partners simultaneously

  • Recombinant antibody fragments optimized for specific applications

• Mass spectrometry-based approaches:

  • Antibody-based immunoprecipitation coupled with mass spectrometry

  • Targeted proteomics with peptide-specific antibodies

  • Spatial proteomics using antibody-based capture

  • Quantitative multiplexed protein profiling

• High-throughput screening platforms:

  • Antibody microarrays for rapid profiling of FAR2 across multiple samples

  • Automated immunohistochemistry systems for standardized detection

  • Machine learning algorithms for quantitative image analysis

  • Droplet-based single-cell antibody assays

• In vivo applications:

  • Development of FAR2-targeted molecular imaging probes

  • Intrabody applications for functional modulation in living systems

  • Antibody-drug conjugates for targeted delivery to FAR2-expressing cells

  • Extracellular vesicle targeting for therapeutic applications

What are the key unresolved questions regarding FAR2's role in disease pathogenesis that researchers should address?

Despite progress in understanding FAR2, several critical questions remain unresolved:

• Mechanism of action in kidney disease:

  • How does FAR2 specifically contribute to mesangial matrix expansion?

  • What is the molecular pathway connecting fatty alcohol production to renal pathology?

  • Does FAR2 function primarily through platelet-activating factor synthesis or other mechanisms?

  • Are there tissue-specific regulatory mechanisms controlling FAR2 in the kidney?

• Genetic regulation:

  • How does the 9-bp sequence in the 5′-UTR mechanistically affect Far2 expression?

  • Are there human genetic variants associated with FAR2 expression and kidney disease risk?

  • What is the complete regulatory network controlling FAR2 expression beyond NKX3.2?

  • How is FAR2 expression epigenetically regulated during disease progression?

• Therapeutic targeting potential:

  • Can selective inhibition of FAR2 prevent or reverse kidney disease progression?

  • Are there compensatory mechanisms that might limit efficacy of FAR2 targeting?

  • What is the therapeutic window for FAR2 modulation without disrupting essential lipid metabolism?

  • How can FAR2-targeted therapies be specifically delivered to affected tissues?

• Biomarker applications:

  • Can FAR2 expression levels serve as prognostic indicators in kidney diseases?

  • Are circulating metabolites related to FAR2 activity useful as non-invasive biomarkers?

  • How does FAR2 expression correlate with traditional markers of kidney function?

  • Can FAR2-related parameters identify patients likely to respond to specific therapies?

• Broader disease associations:

  • Beyond kidney diseases, what other pathological conditions involve FAR2 dysregulation?

  • Does FAR2 play roles in other organs where peroxisomal function is critical?

  • How does FAR2 contribute to age-related pathologies given its role in age-associated MME?

  • Are there connections between FAR2 and metabolic disorders involving lipid metabolism?

The advancement of these research questions will require integrated approaches combining molecular techniques, animal models, and clinical investigations, with FAR2 antibodies serving as essential tools throughout this process.