irf2bp1 Antibody

What is IRF2BP1 and what cellular functions does it perform?

IRF2BP1 (Interferon Regulatory Factor 2 Binding Protein 1) functions primarily as a transcriptional repressor and corepressor that works in an IRF2-dependent manner. This repression is not mediated by histone deacetylase activities . The protein may also act as an E3 ubiquitin ligase towards JDP2, enhancing its polyubiquitination, and is known to repress ATF2-dependent transcriptional activation . IRF2BP1 is predominantly localized in the nucleus, consistent with its role in transcriptional regulation . Understanding these functions is essential when designing experiments targeting IRF2BP1 in various cellular contexts and pathways.

Which applications are suitable for IRF2BP1 antibodies in research settings?

IRF2BP1 antibodies have been validated for multiple research applications with specific dilution requirements:

For optimal results, researchers should perform antibody titration in their specific experimental systems, as sensitivity can vary across tissue types and preparation methods .

What species reactivity do commercially available IRF2BP1 antibodies demonstrate?

Commercial IRF2BP1 antibodies show cross-reactivity with multiple mammalian species:

• The Proteintech antibody (13698-1-AP) has confirmed reactivity with human, mouse, and rat samples

• The Elabscience antibody (E-AB-52039) reacts with human and mouse samples

• The Thermo Fisher antibody (PA5-65562) shows high sequence identity with mouse (95%) and rat (96%) orthologs, suggesting cross-reactivity with these species

This cross-reactivity is particularly valuable for comparative studies across model organisms and translational research connecting animal models to human systems.

How should Western blot protocols be optimized when using IRF2BP1 antibodies?

When designing Western blot experiments with IRF2BP1 antibodies, consider the following optimization approaches:

• Sample preparation: Effective extraction of nuclear proteins is essential since IRF2BP1 is primarily nuclear localized

• Antibody dilution: Use within the 1:500-1:1000 range for optimal signal-to-noise ratio

• Molecular weight expectations: Prepare to detect bands in the 62-72 kDa range, as the observed molecular weight may vary from the calculated weight (62 kDa) due to post-translational modifications

• Positive controls: Include lysates from HeLa, HEK-293, or Jurkat cells as positive controls, which have been validated for IRF2BP1 expression

• Buffer conditions: Use PBS with 0.02% sodium azide and 50% glycerol at pH 7.3 for antibody dilution to maintain optimal activity

Researchers should refer to specific protocols provided by antibody manufacturers for optimal results in their experimental systems.

What antigen retrieval methods are recommended for IRF2BP1 immunohistochemistry?

Successful IRF2BP1 immunohistochemistry depends significantly on effective antigen retrieval:

• Primary recommendation: Use TE buffer at pH 9.0 for optimal epitope exposure in paraffin-embedded tissues

• Alternative method: Citrate buffer at pH 6.0 can be used as an alternative retrieval method if TE buffer yields suboptimal results

• Tissue-specific considerations: For human esophagus cancer and thyroid cancer tissues, specific protocols provided by Elabscience should be followed with recommended dilutions of 1:30-1:150

• Incubation conditions: After retrieval, allow sections to cool to room temperature before antibody application

• Blocking optimization: Implement appropriate blocking steps to reduce background staining, especially in tissues with high endogenous peroxidase activity

Testing both retrieval methods in parallel on serial sections is recommended to determine the optimal approach for your specific tissue type and fixation conditions.

How can researchers validate the specificity of IRF2BP1 antibodies?

Rigorous validation of IRF2BP1 antibody specificity should include:

• Negative controls: Utilize gene knockout/knockdown approaches (siRNA, CRISPR-Cas9) to confirm signal reduction

• Peptide competition assays: Pre-incubate antibody with immunogen peptide to demonstrate specific epitope binding

• Multiple antibody comparison: Test antibodies raised against different epitopes of IRF2BP1 to confirm concordant patterns

• Recombinant protein expression: Overexpress tagged IRF2BP1 and confirm co-localization with antibody staining

• Cross-reactivity testing: Examine expression in tissues known to express or lack IRF2BP1 based on transcriptomic data

The observed molecular weight of 62-72 kDa compared to the calculated 62 kDa weight provides a useful reference point for validation . Signal at the expected molecular weight in appropriate positive control samples (e.g., HeLa cells, HEK-293 cells) strongly supports antibody specificity.

How can IRF2BP1 antibodies be utilized in protein-protein interaction studies?

IRF2BP1 antibodies can effectively investigate protein interactions through:

• Co-immunoprecipitation: IRF2BP1 antibodies have been validated for IP applications in HEK-293 cells, making them suitable for pulling down IRF2BP1 and its interaction partners . Use 0.5-4.0 μg antibody per 1.0-3.0 mg of protein lysate for optimal results.

• Proximity ligation assay (PLA): Combine IRF2BP1 antibodies with antibodies against suspected interaction partners to visualize protein proximities in situ.

• ChIP-reChIP: For investigating co-occupancy of IRF2BP1 with other transcription factors at genomic loci, sequential ChIP can be performed with IRF2BP1 antibodies followed by IP with antibodies against interaction partners.

• Mass spectrometry identification: After IP with IRF2BP1 antibodies, MS analysis can identify novel interaction partners and complex components.

• IRF2-dependent interactions: Given IRF2BP1's established role as an IRF2 corepressor , parallel IP experiments with both factors can elucidate cooperative binding networks.

When designing these experiments, consider that IRF2BP1 functions as a transcriptional repressor and E3 ligase, suggesting interactions with both transcriptional machinery and ubiquitination pathway components.

What are key considerations for chromatin immunoprecipitation experiments with IRF2BP1 antibodies?

For successful ChIP experiments targeting IRF2BP1:

• Crosslinking optimization: Since IRF2BP1 functions as a transcriptional repressor , standard formaldehyde fixation (1% for 10 minutes) is appropriate for capturing DNA-protein interactions.

• Sonication parameters: Optimize sonication to achieve chromatin fragments of 200-500 bp for high-resolution binding site identification.

• Antibody selection: Choose antibodies validated for ChIP applications to ensure effective immunoprecipitation of chromatin-bound IRF2BP1.

• Binding site analysis: As IRF2BP1 is a transcriptional repressor that functions with IRF2 , analyze data for co-occurrence with IRF2 binding motifs and correlation with repressed gene expression.

• Controls: Include input controls, IgG controls, and positive controls targeting known IRF2BP1-regulated loci.

Published applications have validated IRF2BP1 antibodies in ChIP experiments , making this a reliable approach for investigating genomic binding sites and transcriptional regulation mechanisms.

How do post-translational modifications affect IRF2BP1 detection by antibodies?

Post-translational modifications (PTMs) can significantly impact IRF2BP1 antibody recognition:

• Molecular weight variations: The observed molecular weight range of 62-72 kDa versus the calculated 62 kDa suggests the presence of PTMs that alter migration patterns.

• Epitope masking: Phosphorylation, ubiquitination, or other modifications near antibody epitopes can block recognition, potentially causing false negatives.

• Cell-specific modifications: Different cell types may exhibit unique PTM patterns of IRF2BP1, explaining variable detection efficiencies across samples.

• Stimulation-dependent changes: As a transcriptional regulator, IRF2BP1 modifications likely change upon cellular stimulation, potentially affecting antibody detection in activated versus resting cells.

• E3 ligase activity: IRF2BP1's potential role as an E3 ubiquitin ligase suggests it may undergo auto-ubiquitination, potentially affecting antibody binding.

Researchers should consider performing phosphatase or deubiquitinase treatments in parallel experiments to assess the impact of specific modifications on antibody recognition when encountering unexpected detection patterns.

Why might researchers observe multiple bands when using IRF2BP1 antibodies in Western blot?

Multiple bands in IRF2BP1 Western blots may result from:

• Isoforms: The IRF2BP1 gene may produce splice variants resulting in proteins of different sizes.

• Post-translational modifications: The variable observed molecular weight (62-72 kDa) suggests modifications like phosphorylation or ubiquitination affect migration patterns.

• Proteolytic processing: Partial degradation during sample preparation can generate fragment bands.

• Cross-reactivity: Antibodies may recognize structurally similar proteins, particularly other IRF-binding proteins.

• Sample-specific expression: Different cell types (e.g., HeLa vs. HEK-293) may express different IRF2BP1 variants or modified forms .

To address this, researchers should:

• Validate with knockout/knockdown controls

• Compare patterns across multiple IRF2BP1 antibodies

• Use phosphatase/deubiquitinase treatments to assess modification contributions

• Implement optimized sample preparation to minimize degradation

How should researchers troubleshoot weak or absent signals in IRF2BP1 immunostaining?

When encountering weak IRF2BP1 immunostaining signals:

• Antigen retrieval optimization: Test both recommended methods (TE buffer pH 9.0 and citrate buffer pH 6.0) to determine which better exposes epitopes in your specific tissue type.

• Antibody concentration: Adjust concentration within the recommended range (1:50-1:500 for IHC) , potentially using higher concentrations for tissues with lower expression.

• Incubation conditions: Extend primary antibody incubation time (overnight at 4°C versus 1-2 hours at room temperature) to improve binding.

• Detection system sensitivity: Switch to more sensitive detection methods (e.g., polymer-based systems, tyramide signal amplification) for low-abundance targets.

• Fixation assessment: Overfixation can mask epitopes; adjust fixation protocols or test samples with different fixation durations.

For research using human cancer tissues, starting with the more concentrated end of the dilution range (1:30-1:50) is recommended based on validated results in esophageal and thyroid cancer samples .

What approaches can resolve contradictory results when using different IRF2BP1 antibodies?

When different IRF2BP1 antibodies yield conflicting results:

• Epitope mapping: Determine the target epitopes of each antibody and assess whether they recognize different domains or isoforms of IRF2BP1.

• Validation using genetic approaches: Apply CRISPR knockout or siRNA knockdown of IRF2BP1 to confirm which antibody signals are specifically reduced.

• Recombinant expression: Overexpress tagged IRF2BP1 and assess which antibodies accurately detect the recombinant protein.

• Cross-validation with orthogonal methods: Confirm expression using RNA-based methods (RT-PCR, RNA-seq) to determine expected expression patterns.

• Context-dependent expression: Consider that different experimental conditions may alter IRF2BP1 conformation or modifications, affecting epitope accessibility.

Understanding the immunogen used for antibody generation is crucial - the Thermo Fisher antibody targets a specific sequence (AETPGVPSPIA...AVSG) , while others may target different regions, potentially explaining discrepancies in detection patterns.

How can IRF2BP1 antibodies be applied in multi-parameter imaging and flow cytometry?

For multi-parameter analyses with IRF2BP1 antibodies:

• Flow cytometry optimization: As IRF2BP1 is predominantly nuclear , effective permeabilization is critical (use Triton X-100 rather than saponin-based methods).

• Antibody panel design: When combining with other nuclear factor antibodies, select fluorophores with minimal spectral overlap and consider antibody species to avoid cross-reactivity.

• Mass cytometry (CyTOF) applications: Metal-conjugated IRF2BP1 antibodies can be incorporated into CyTOF panels for high-dimensional analysis of transcription factor networks.

• Imaging cytometry: Combine with cytoplasmic markers to correlate IRF2BP1 expression with cellular phenotypes in heterogeneous populations.

• Sorting strategies: Use IRF2BP1 staining in combination with other transcription factors to isolate specific cellular subsets for downstream analysis.

Given the recommended 1:50-1:500 dilution range for immunofluorescence applications , researchers should perform titration experiments to determine optimal concentrations for flow cytometry applications.

What methods can investigate the relationship between IRF2BP1 and other transcription factors?

To study IRF2BP1 interactions with transcriptional networks:

• Sequential ChIP: Use IRF2BP1 antibodies in combination with antibodies against IRF2 or other transcription factors to identify co-occupied genomic regions.

• ChIP-seq integration: Compare IRF2BP1 ChIP-seq data with datasets for IRF2 and other factors to identify cooperative or antagonistic binding patterns.

• Co-immunoprecipitation assays: Leverage the validated IP application of IRF2BP1 antibodies to pull down transcription factor complexes.

• Proximity-dependent labeling: Use BioID or APEX2 fusions with IRF2BP1 to identify nearby proteins in living cells.

• Reporter assays: Combine with mutation of IRF2BP1 binding sites to quantify transcriptional repression effects on target genes.

Since IRF2BP1 acts as a transcriptional corepressor in an IRF2-dependent manner , particular attention should be paid to investigating this partnership through co-occupancy studies at target promoters.

How can researchers investigate IRF2BP1's potential E3 ligase activity with current antibodies?

To study the E3 ligase functions of IRF2BP1:

• Ubiquitination assays: Use IRF2BP1 antibodies to immunoprecipitate the protein complex, then probe for ubiquitinated substrates (particularly JDP2) .

• In vitro ubiquitination: Perform reconstituted ubiquitination assays with immunopurified IRF2BP1 to confirm intrinsic E3 ligase activity.

• Domain-specific antibodies: Consider antibodies targeting the RING domain to specifically study the E3 ligase function separate from transcriptional repression.

• Substrate identification: Combine IRF2BP1 knockdown with proteome-wide ubiquitination profiling to identify novel substrates beyond JDP2.

• PTM crosstalk: Investigate how phosphorylation or other modifications of IRF2BP1 might regulate its E3 ligase activity using phospho-specific antibodies in combination with ubiquitination assays.