fads2 Antibody

What is FADS2 and why is it significant in metabolic research?

FADS2 (Fatty Acid Desaturase 2) is an enzyme that plays a crucial role in the biosynthesis of highly unsaturated fatty acids (HUFAs) from essential polyunsaturated fatty acids (PUFAs). It functions as a fatty acyl-coenzyme A (CoA) desaturase that introduces cis double bonds at carbon 6 of fatty acyl chains. FADS2 catalyzes the first and rate-limiting step in the pathway that converts linoleic acid (LA, 18:2n-6) and alpha-linolenic acid (ALA, 18:3n-3) into gamma-linoleate (GLA, 18:3n-6) and stearidonate (18:4n-3), respectively . Beyond this primary function, FADS2 has gained significant research interest for its role in cancer metabolism, particularly in conferring resistance to SCD1 inhibitors through the synthesis of sapienic acid from palmitic acid . The enzyme's diverse metabolic functions make it an important target for research in lipid metabolism, metabolic disorders, and cancer biology.

What are the key considerations when selecting a FADS2 antibody for research applications?

When selecting a FADS2 antibody for research, consider these critical factors:

• Validation status: Choose antibodies that have been knockout (KO) tested, as this provides definitive evidence of specificity. For example, ab72189 has been validated using FADS2 knockout cell lines, showing specific binding at 40-45 kDa in wild-type A549 cells with no signal in FADS2 knockout lines .

• Species reactivity: Confirm that the antibody reacts with your species of interest. Both antibodies in the search results (ab72189 and 28034-1-AP) show reactivity with human samples, while 28034-1-AP also reacts with mouse and rat samples .

• Application compatibility: Verify the antibody is validated for your specific application. For instance, ab72189 is suitable for immunoprecipitation (IP) and Western blotting (WB) , while 28034-1-AP is validated for WB, IHC, IF, and ELISA applications .

• Isoform recognition: FADS2 has multiple isoforms (with molecular weights of approximately 52 kDa, 49 kDa, and 45 kDa). Some antibodies may preferentially detect specific isoforms, so check if the antibody recognizes your isoform of interest .

• Publication record: Antibodies cited in peer-reviewed publications provide additional confidence. The antibodies mentioned in the search results have been cited in multiple publications for various applications .

How do I interpret the apparent molecular weight discrepancy between predicted and observed FADS2 in Western blots?

The molecular weight discrepancy between predicted (52 kDa) and observed (40-45 kDa) FADS2 protein in Western blots is a common source of confusion. There are several methodological explanations:

• Multiple isoforms: FADS2 has three known isoforms with different molecular weights: isoform 1 at 52 kDa, isoform 2 at 49 kDa, and isoform 3 at 45 kDa according to SwissProt data. The 45 kDa band often observed in Western blots likely represents isoform 3 .

• Post-translational modifications: These can affect protein migration on SDS-PAGE, causing apparent molecular weights to differ from predicted values based on amino acid sequence alone.

• Tissue-specific expression patterns: Different tissues may express different isoforms. For example, ab72189 detects a strong band at 45 kDa in human liver and brain tissue lysates, as well as in HeLa and HepG2 whole cell lysates .

• Validation through knockout controls: To confirm band identity, compare wild-type and FADS2 knockout samples. In one validation study, wild-type A549 cells showed bands at 40-45 kDa that were absent in FADS2 knockout A549 cells, confirming specificity despite the molecular weight difference .

What are the optimal conditions for using FADS2 antibodies in Western blotting?

For optimal Western blotting with FADS2 antibodies, follow these research-validated protocols:

Sample preparation and loading:

• Use 10-20 μg of whole cell lysate or tissue lysate per lane

• Include appropriate positive controls (HeLa cells, HepG2 cells, liver tissue)

• Always include loading controls (e.g., calnexin)

Antibody dilutions and incubation:

• For ab72189: Use at 1 μg/mL concentration

• For 28034-1-AP: Use at 1:500-1:2000 dilution

• Incubate primary antibody overnight at 4°C for optimal results

Detection system:

• For ab72189: Secondary antibody options include:

  • Goat anti-Rabbit IgG H&L 800CW (for fluorescent detection)

  • Mouse monoclonal [SB62a] to Rabbit IgG light chain (HRP) for chemiluminescent detection

• For 28034-1-AP: Standard HRP-conjugated secondary antibodies appropriate for rabbit IgG

Expected results:

• Major bands typically appear at 40-45 kDa and sometimes at 52 kDa

• Validate specificity using FADS2 knockout cells if available

How can I optimize immunoprecipitation protocols for FADS2 protein complexes?

For successful immunoprecipitation of FADS2 and its interaction partners:

• Lysate preparation:

  • Use 0.5 mg of whole cell extract (e.g., HepG2 cells) for optimal results

  • Dilute lysates in RIPA buffer to maintain protein interactions while ensuring adequate solubilization

• Antibody amount:

  • Use 5 μg of FADS2 antibody (e.g., ab72189) per immunoprecipitation reaction

  • Include a no-antibody control to identify non-specific binding

• Immunoprecipitation procedure:

  • Pre-incubate antibody with 50 μl of protein G magnetic beads for 10 minutes under agitation

  • Add diluted cell lysate and incubate for an additional 10 minutes under agitation

  • For more stringent conditions, extend incubation time or adjust buffer composition

• Washing and elution:

  • Perform stringent washes to remove non-specific binding

  • Elute proteins by adding SDS loading buffer and incubating at 70°C for 10 minutes

• Detection:

  • Run 10 μl of each eluted sample on SDS-PAGE

  • When probing with anti-FADS2, expect to see a band at approximately 45 kDa in the immunoprecipitated sample but not in the control

What are the recommended protocols for immunohistochemistry using FADS2 antibodies?

For immunohistochemistry applications with FADS2 antibodies:

• Tissue preparation:

  • Use formalin-fixed, paraffin-embedded (FFPE) tissue sections

  • For fresh tissues, fixation with 4% paraformaldehyde is recommended

• Antigen retrieval:

  • Primary recommendation: Use TE buffer at pH 9.0

  • Alternative: Citrate buffer at pH 6.0 may also be effective

  • Heat-induced epitope retrieval methods (pressure cooker or microwave) yield optimal results

• Antibody concentration:

  • For 28034-1-AP: Use at 1:50-1:500 dilution

  • Perform antibody titration for each new tissue type to determine optimal concentration

• Detection system:

  • Use polymer-based detection systems for improved sensitivity

  • DAB (3,3'-diaminobenzidine) is the recommended chromogen

• Positive controls:

  • Mouse heart tissue has been validated as a positive control for FADS2 staining

  • Liver tissue sections also show strong FADS2 expression and can serve as effective positive controls

• Visualization patterns:

  • FADS2 shows primarily cytoplasmic localization with enrichment in endoplasmic reticulum regions

  • Expression intensity may vary depending on tissue metabolic state

How can FADS2 antibodies be used to investigate cancer cell metabolism and SCD1 inhibitor resistance?

FADS2 antibodies are powerful tools for investigating the emerging role of FADS2 in cancer metabolism, particularly in the context of SCD1 inhibitor resistance:

• Monitoring FADS2 expression changes:

  • Western blotting with FADS2 antibodies can detect upregulation of FADS2 in response to SCD1 inhibition in resistant cancer cell lines (e.g., A549 and HeLa cells)

  • This approach helps identify the alternative fatty acid metabolism pathways activated during treatment

• Correlation with drug resistance phenotypes:

  • Compare FADS2 expression levels by Western blot across multiple cancer cell lines with varying sensitivity to SCD1 inhibitors

  • Recent research has demonstrated that SCD1 inhibitor-resistant cancer cells (A549 and HeLa) show increased FADS2 expression in response to SCD1 inhibition, while sensitive cells (LK-2 and SiHa) do not

• Mechanistic studies:

  • Use FADS2 antibodies in immunoprecipitation experiments to identify interaction partners that may contribute to resistance mechanisms

  • Combine with mass spectrometry analysis to map the FADS2 interactome in sensitive versus resistant cells

• Biomarker development:

  • Immunohistochemistry with FADS2 antibodies on patient-derived xenografts or tumor samples to evaluate potential clinical correlations between FADS2 expression and treatment outcomes

  • Establish FADS2 expression thresholds that predict resistance to SCD1-targeted therapies

• Combination therapy strategies:

  • Monitor FADS2 and SCD1 expression simultaneously to develop rational combination strategies targeting both pathways

  • Test whether inhibiting FADS2 can restore sensitivity to SCD1 inhibitors in resistant cells

What approaches can be used to distinguish between FADS2 isoforms in experimental systems?

Distinguishing between FADS2 isoforms requires specialized approaches:

• Isoform-specific Western blotting:

  • Use gradient gels (e.g., 8-16%) to better separate the closely migrating isoforms (52 kDa, 49 kDa, and 45 kDa)

  • Include recombinant protein standards for each isoform as positive controls

  • Some antibodies may preferentially detect specific isoforms; ab72189 appears to show stronger detection of the 45 kDa isoform (isoform 3)

• RT-PCR and qPCR analysis:

  • Design primers specific to the unique regions of each isoform transcript

  • Perform qPCR to quantify relative expression levels of different isoforms across tissues or experimental conditions

• Immunoprecipitation followed by mass spectrometry:

  • Immunoprecipitate FADS2 using antibodies like ab72189

  • Perform high-resolution mass spectrometry to identify peptides unique to each isoform

  • This approach can provide quantitative data on the relative abundance of each isoform

• Isoform-specific knockdown:

  • Design siRNAs targeting unique regions of each isoform

  • Validate knockdown specificity using Western blotting with antibodies that detect all isoforms

  • This approach helps determine the functional contribution of each isoform

• Recombinant expression systems:

  • Express individual FADS2 isoforms in appropriate model systems

  • Compare molecular weights and antibody reactivity patterns

  • This creates valuable positive controls for isoform identification

How can I integrate FADS2 antibody-based detection with lipid profiling to study metabolic pathways?

Integrating FADS2 protein detection with comprehensive lipid profiling provides powerful insights into fatty acid metabolism:

• Coordinated sample preparation:

  • Split biological samples for parallel protein extraction (for Western blotting) and lipid extraction (for mass spectrometry)

  • Ensure samples represent identical experimental conditions for direct correlation

• Quantitative Western blotting:

  • Use FADS2 antibodies with fluorescent secondary antibodies for precise quantification

  • Include recombinant FADS2 protein standards for absolute quantification

  • Normalize to appropriate housekeeping proteins

• Lipid profiling by mass spectrometry:

  • Perform targeted analysis of FADS2 substrates and products:

    • Substrates: linoleic acid (18:2n-6), alpha-linolenic acid (18:3n-3), palmitic acid (16:0)

    • Products: gamma-linoleate (18:3n-6), stearidonate (18:4n-3), sapienic acid (16:1n-10)

  • Use internal standards for accurate quantification

• Activity assays coupled with protein detection:

  • Measure FADS2 enzymatic activity using radiolabeled or stable isotope-labeled substrates

  • Correlate activity measurements with protein expression levels determined by Western blotting

  • This approach distinguishes between changes in expression versus changes in specific activity

• Integrative data analysis:

  • Calculate substrate/product ratios for FADS2-mediated reactions

  • Correlate these ratios with FADS2 protein levels determined by Western blotting

  • Use multivariate statistical methods to identify relationships between FADS2 expression and broader lipid metabolism patterns

What are common causes of inconsistent FADS2 antibody performance in Western blots?

When troubleshooting inconsistent FADS2 Western blot results, consider these methodological factors:

• Multiple band patterns:

  • FADS2 naturally exists in multiple isoforms (52 kDa, 49 kDa, and 45 kDa)

  • Different tissues/cells may express different isoform combinations

  • Solution: Include positive controls with known isoform expression patterns

• Weak or absent signal:

  • Sample degradation: FADS2 may be sensitive to freeze-thaw cycles

  • Insufficient protein loading: Increase sample amount (10-20 μg recommended)

  • Solution: Use freshly prepared samples and optimize protein extraction methods

• Non-specific bands:

  • Inadequate blocking: Optimize blocking conditions (5% BSA recommended)

  • Insufficient washing: Increase wash volume and duration

  • Solution: Validate antibody specificity using FADS2 knockout samples if available

• Inconsistent band molecular weights:

  • Post-translational modifications may vary between samples

  • Differences in gel systems or running conditions

  • Solution: Include molecular weight markers and standardize electrophoresis conditions

• Tissue-specific considerations:

  • FADS2 expression varies significantly between tissues

  • Expression may be regulated by nutritional status or experimental conditions

  • Solution: Consider tissue-specific positive controls (e.g., liver tissue shows reliable expression)

How can researchers distinguish between specific and non-specific binding in immunohistochemistry using FADS2 antibodies?

To ensure specificity in FADS2 immunohistochemistry:

• Comprehensive controls:

  • Positive control: Include tissues with known FADS2 expression (mouse heart tissue, liver tissue)

  • Negative control: Omit primary antibody but perform all other steps identically

  • Absorption control: Pre-incubate antibody with recombinant FADS2 protein before staining

  • Genetic control: When possible, use tissue from FADS2 knockout animals

• Antigen retrieval optimization:

  • Test multiple antigen retrieval methods:

    • TE buffer (pH 9.0) is recommended for 28034-1-AP

    • Citrate buffer (pH 6.0) can be used as an alternative

  • Incomplete antigen retrieval can lead to false-negative results

• Antibody titration:

  • Perform a dilution series (e.g., 1:50, 1:100, 1:200, 1:500) to identify optimal concentration

  • Too high concentration increases background; too low reduces specific signal

• Expected staining pattern verification:

  • FADS2 should show predominantly cytoplasmic localization

  • Enrichment in endoplasmic reticulum regions is consistent with its biological function

  • Nuclear staining is typically considered non-specific

• Multiple antibody validation:

  • Use two different FADS2 antibodies targeting different epitopes

  • Concordant staining patterns strongly support specificity

How should researchers interpret contradictory results between FADS2 protein expression and functional assays?

When FADS2 protein expression (determined by antibody-based methods) doesn't correlate with enzymatic activity or metabolic outcomes:

• Post-translational regulation considerations:

  • FADS2 activity may be regulated by phosphorylation or other modifications

  • Western blotting detects total protein but doesn't indicate active state

  • Solution: Consider using phospho-specific antibodies if available or activity-based protein profiling

• Substrate availability effects:

  • FADS2 requires specific fatty acid substrates and cofactors for activity

  • Protein may be present but inactive due to substrate limitations

  • Solution: Measure substrate levels in parallel with protein expression

• Competitive enzyme dynamics:

  • Other desaturases might compete for the same substrates

  • Measure expression of related enzymes (e.g., SCD1, SCD5) to identify potential compensatory mechanisms

  • Solution: Comprehensive expression profiling of the fatty acid desaturation pathway

• Isoform-specific functions:

  • Different FADS2 isoforms may have distinct substrate preferences or activities

  • The antibody may detect all isoforms but only some contribute to the measured activity

  • Solution: Isoform-specific activity assays or selective knockdown experiments

• Integration of multiple approaches:

  • Combine protein detection (Western blot) with activity assays and metabolite profiling

  • Measure substrate-to-product ratios for specific FADS2-catalyzed reactions

  • Investigate potential inhibitory factors or enzyme modulators in the experimental system

How can FADS2 antibodies be used to study the role of fatty acid metabolism in cancer drug resistance?

Recent research has revealed FADS2's critical role in cancer drug resistance mechanisms:

• Resistance mechanism profiling:

  • Use FADS2 antibodies to screen cancer cell lines for expression changes following treatment with SCD1 inhibitors or other metabolic-targeting drugs

  • Western blot analysis has demonstrated that SCD1 inhibitor-resistant cancer cell lines (A549 and HeLa) upregulate FADS2 expression in response to treatment, while sensitive cell lines (LK-2 and SiHa) do not

• Correlation with ER stress markers:

  • Perform dual staining with FADS2 and ER stress markers (GRP78, phosphorylated eIF2α, CHOP)

  • Research indicates that FADS2-mediated resistance to SCD1 inhibitors may involve modulation of the ER stress response

• Fatty acid metabolism reprogramming:

  • Use FADS2 antibodies in combination with metabolomic profiling to track shifts in fatty acid metabolism

  • Focus on the production of sapienic acid and its elongation product, cis-8-octadecenoate, which can compensate for monounsaturated fatty acid depletion in resistant cells

• Therapeutic targeting strategies:

  • Develop combination therapy approaches targeting both SCD1 and FADS2 pathways

  • Use FADS2 antibodies to monitor target engagement in preclinical models

• Translational biomarker development:

  • Evaluate FADS2 expression in patient-derived samples using immunohistochemistry

  • Correlate expression patterns with treatment response and clinical outcomes

What methodological approaches combine FADS2 antibody-based detection with functional genomics to study metabolic regulation?

Integrating FADS2 protein detection with functional genomics provides comprehensive insights:

• CRISPR-Cas9 screening with protein validation:

  • Perform genome-wide CRISPR screens to identify regulators of FADS2 expression or activity

  • Validate hits by measuring FADS2 protein levels using Western blotting

  • This approach identifies both transcriptional and post-transcriptional regulatory mechanisms

• ChIP-seq coupled with protein expression analysis:

  • Identify transcription factors that bind the FADS2 promoter using ChIP-seq

  • Correlate binding events with FADS2 protein expression under various conditions

  • This approach maps the regulatory network controlling FADS2 expression

• Multi-omics data integration:

  • Collect parallel data on:

    • FADS2 protein expression (antibody-based detection)

    • Transcriptome (RNA-seq)

    • Lipidome (targeted LC-MS/MS)

  • Integrate these datasets to identify regulatory mechanisms and metabolic consequences

• Genetic variation studies:

  • Analyze FADS2 protein expression across cell lines with different genetic backgrounds

  • Correlate expression patterns with known genetic variants in the FADS gene cluster

  • This approach connects genotype to protein expression phenotypes

• Single-cell analysis:

  • Perform single-cell Western blotting or mass cytometry with FADS2 antibodies

  • Combine with single-cell RNA-seq data for integrated analysis of expression heterogeneity

  • This reveals cell-to-cell variability in FADS2 expression and regulation