BRI3BP Antibody

What is BRI3BP and what cellular functions does it perform?

BRI3BP (BRI3 Binding Protein) is a protein-coding gene located in the mitochondrion that is involved in tumorigenesis. It may function by stabilizing p53/TP53 and plays a significant role in cancer progression . Recent research has revealed that BRI3BP interacts with K-Ras4B and K-Ras4A, suggesting it operates within the recycling endosomal compartment to regulate K-Ras localization to the plasma membrane . BRI3BP is also known as KG19, BNAS1, HCCR-1, HCCR-2, or HCCRBP-1 .

Which BRI3BP antibody applications are most commonly used in current research?

The most common applications for BRI3BP antibodies in current research include:

• Western Blotting (WB): Used at dilutions ranging from 1:500-1:2000

• Immunohistochemistry (IHC): Used at dilutions of 1:20-1:150

• Enzyme-Linked Immunosorbent Assay (ELISA): Used at dilutions of 1:5000-1:10000

• Immunofluorescence (IF)

• Immunocytochemistry (ICC)

These applications enable visualization and quantification of BRI3BP in various experimental contexts, with specific dilution protocols optimized for each technique .

What is the difference between using monoclonal versus polyclonal BRI3BP antibodies?

Monoclonal BRI3BP antibodies:

• Are derived from a single B-cell clone, recognizing a single epitope

• Offer consistent lot-to-lot reproducibility with minimal batch variation

• Typically have higher specificity but lower sensitivity

• Example: Mouse monoclonal anti-BRI3BP antibody (clone 3H1) raised against a full-length recombinant BRI3BP

Polyclonal BRI3BP antibodies:

• Are derived from multiple B-cell clones, recognizing multiple epitopes

• Generally offer higher sensitivity but may have more batch-to-batch variation

• May detect denatured proteins more effectively in some applications

• Example: Rabbit polyclonal antibodies generated against synthetic peptides of human BRI3BP

The choice between them depends on the experimental requirements: use monoclonals when absolute specificity is crucial, and polyclonals when detection sensitivity is prioritized .

What is the optimal protocol for BRI3BP immunohistochemistry in formalin-fixed paraffin-embedded tissues?

The optimal protocol for BRI3BP immunohistochemistry in FFPE tissues involves:

• Tissue preparation:

  • Section FFPE tissues at 4μm thickness

  • Place on positively charged microscope slides

• Antigen retrieval:

  • Dewax sections in xylene

  • Rehydrate in alcohols of descending grade (100% to distilled water)

  • Perform microwave-based antigen retrieval using citrate buffer pH 6 at 1,000W for 20 minutes

• Antibody incubation:

  • Block endogenous peroxidase with methanol/hydrogen peroxide solution

  • Block non-specific binding with 2% BSA in PBS

  • Incubate with primary rabbit polyclonal anti-BRI3BP antibody (e.g., NBP188564) at 1:10-1:50 dilution for 1 hour at room temperature

  • Wash with PBS

  • Apply biotinylated secondary antibody (1:200 dilution) for 40 minutes

  • Incubate with avidin-biotin complex for 30 minutes

• Visualization and counterstaining:

  • Develop with diaminobenzidine (DAB)

  • Counterstain with Mayer's hematoxylin

  • Process through graded alcohols and xylene

  • Mount in DPX

• Controls:

  • Include positive controls (colon cancer tissue is recommended)

  • Include negative controls by omitting primary antibody

How should Western blot protocols be optimized for BRI3BP detection?

For optimal BRI3BP detection via Western blot:

• Sample preparation:

  • Extract proteins using RIPA buffer supplemented with protease inhibitors

  • Quantify protein concentration using Bradford or BCA assay

  • Use 20-40 μg of total protein per lane

• Gel electrophoresis parameters:

  • Use 10-12% polyacrylamide gels

  • Run at 100-120V until adequate separation

• Transfer conditions:

  • Transfer to PVDF membrane at 100V for 1 hour or 30V overnight at 4°C

  • Verify transfer efficiency with Ponceau S staining

• Antibody incubation:

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

  • Incubate with primary BRI3BP antibody at 1:500-1:2000 dilution in blocking buffer overnight at 4°C

  • Wash 3×10 minutes with TBST

  • Incubate with HRP-conjugated secondary antibody (1:5000-1:10000) for 1 hour

  • Wash 3×10 minutes with TBST

• Detection:

  • Develop using enhanced chemiluminescence substrate

  • Expected molecular weight: BRI3BP appears at approximately 28 kDa

• Controls:

  • Include positive control lysates known to express BRI3BP

  • Consider including recombinant BRI3BP protein as reference

What are the validated BRI3BP antibody dilutions for different experimental applications?

Based on manufacturer recommendations and published research, the validated dilutions for BRI3BP antibodies are:

These ranges should be optimized based on specific antibody characteristics, sample type, and detection method sensitivity .

How is BRI3BP expression correlated with breast cancer prognosis and clinical outcomes?

BRI3BP expression has significant associations with breast cancer prognosis:

• Transcriptomic level findings:

  • High BRI3BP mRNA expression correlates with aggressive tumor features including:

    • Large tumor size (P<0.001 in METABRIC and P=0.001 in TCGA)

    • High histological grade (P=0.03 in METABRIC and P<0.001 in TCGA)

    • Lymphovascular invasion positivity (P=0.02 in METABRIC and P<0.001 in TCGA)

  • In METABRIC cohort (n=1,980), high BRI3BP mRNA was associated with ER+ (P<0.001) and PR+ (P=0.008) status

  • In TCGA cohort (n=854), high BRI3BP mRNA was associated with HER2 positivity (P<0.001)

• Proteomic level findings:

  • High BRI3BP protein expression correlates with:

    • High tumor grade (P<0.001)

    • Hormone receptor negativity (ER- P=0.003, PR- P=0.002)

    • High Ki67 expression (P=0.004)

  • BRI3BP protein expression is highest in triple-negative breast cancer subtypes, followed by HER2+, ER+/HER2- high proliferation, and ER+/HER2- low proliferation (P=0.001)

These correlations indicate that BRI3BP is a potential prognostic marker in breast cancer, with high expression generally associated with more aggressive disease features and potentially poorer outcomes .

What is the role of BRI3BP in K-Ras signaling and how does this impact cancer progression?

BRI3BP plays a crucial role in K-Ras signaling and cancer progression:

• Regulation of K-Ras membrane localization:

  • BRI3BP was identified as a novel binding partner for Ras proteins

  • K-Ras4B plasma membrane localization is reduced in the absence of BRI3BP

  • BRI3BP interacts with both K-Ras4B and K-Ras4A isoforms

• Subcellular trafficking mechanism:

  • BRI3BP functions within the recycling endosomal compartment

  • It regulates K-Ras localization to the plasma membrane, which is necessary for proper signaling

• Evidence supporting BRI3BP-K-Ras interaction:

  • Mass spectrometry analysis identified BRI3BP as a protein that co-immunoprecipitates with K-Ras

  • BRI3BP co-immunoprecipitated with K-Ras in pancreatic and lung cancer cell lines expressing different K-Ras mutant alleles (G12V, G12D, and G12C)

• Impact on cancer progression:

  • Membrane localization of Ras proteins is necessary for their biological functions and oncogenic activity

  • BRI3BP's role in maintaining K-Ras membrane localization suggests it could support oncogenic K-Ras signaling

  • This interaction represents a potential therapeutic target for cancers driven by K-Ras mutations, which include pancreatic, colorectal, and lung cancers

How does BRI3BP influence p53 stability and what are the implications for apoptotic pathways in cancer cells?

BRI3BP exerts complex effects on p53 stability and apoptotic pathways:

These seemingly contradictory findings indicate that BRI3BP's effect on apoptosis may be context-dependent and influenced by cell type, cancer stage, and interaction with specific treatment agents .

What control samples are recommended when validating a new BRI3BP antibody for research use?

When validating a new BRI3BP antibody, comprehensive controls should include:

• Positive tissue controls:

  • Colon cancer tissue (recommended by antibody manufacturers)

  • Breast cancer tissue (particularly triple-negative or HER2+ subtypes)

  • Normal tissues with known BRI3BP expression (based on Human Protein Atlas data)

• Cellular controls:

  • Cell lines with confirmed high BRI3BP expression

  • Cell lines with CRISPR-mediated BRI3BP knockout (negative control)

  • Cells with siRNA-mediated BRI3BP knockdown (reduced expression control)

• Molecular controls:

  • Recombinant BRI3BP protein (full-length or specific domains)

  • Competing peptide corresponding to the immunogen sequence

  • BRI3BP-overexpressing cell lysates

• Technical controls:

  • Primary antibody omission control

  • Isotype-matched irrelevant antibody control

  • Secondary antibody-only control to assess non-specific binding

• Validation approaches:

  • Multiple antibody approach: Test multiple antibodies targeting different epitopes

  • Orthogonal validation: Compare antibody results with mRNA expression data

  • Specificity test on protein arrays containing target protein plus 383 other non-specific proteins

How can researchers overcome challenges in detecting low abundance BRI3BP expression in tissue samples?

To enhance detection of low abundance BRI3BP in tissue samples:

• Sample preparation optimization:

  • Use fresh or properly preserved samples (cold ischemia time <30 minutes)

  • Optimize fixation protocols (24 hours in 10% neutral buffered formalin)

  • Consider antigen retrieval methods beyond standard protocols (extended microwave treatment in citrate buffer)

• Signal amplification strategies:

  • Employ tyramide signal amplification (TSA) systems for IHC

  • Use polymer-based detection systems instead of standard ABC methods

  • Consider catalyzed reporter deposition amplification methods

• Antibody selection and protocol refinements:

  • Choose antibodies with higher affinity (lower Kd values)

  • Extend primary antibody incubation (overnight at 4°C)

  • Reduce antibody dilution (use more concentrated antibody)

  • Use lower stringency wash buffers

• Detection system enhancement:

  • Utilize highly sensitive chromogens for IHC

  • For IF applications, use brighter fluorophores and confocal microscopy

  • For WB, use enhanced chemiluminescent substrates or fluorescent detection

• Quantification approaches:

  • Implement modified H-score assessment for cytoplasmic expression

  • Multiply staining intensity (0-3) by percentage of positive cells

  • Establish proper scoring threshold (e.g., H-score >145 was used to define high BRI3BP expression)

  • Ensure multiple independent scorers for consistency (ICC >0.90)

What are the recommended strategies for multiplexed detection of BRI3BP with other biomarkers in breast cancer tissues?

For effective multiplexed detection of BRI3BP with other breast cancer biomarkers:

• Chromogenic multiplex IHC approaches:

  • Sequential IHC with different chromogens (DAB, AEC, Fast Blue)

  • Use antibodies from different host species to avoid cross-reactivity

  • Implement heat-mediated antibody stripping between rounds

  • Consider automated platforms like Ventana or Leica Bond systems

• Fluorescence-based multiplexing:

  • Multicolor immunofluorescence with spectrally distinct fluorophores

  • Tyramide signal amplification (TSA) with sequential rounds of staining

  • Use of quantum dots for enhanced signal stability and multiplexing capacity

• Recommended biomarker combinations:

  • BRI3BP + standard markers (ER, PR, HER2, Ki67)

  • BRI3BP + apoptosis markers (p53, cleaved caspase-3)

  • BRI3BP + K-Ras pathway components

  • BRI3BP + mitochondrial markers (given its mitochondrial localization)

• Analysis approaches:

  • Use digital pathology systems for quantitative assessment

  • Implement machine learning algorithms for pattern recognition

  • Calculate co-localization coefficients for protein interaction studies

• Validation of multiplex results:

  • Compare with single-plex staining on consecutive sections

  • Validate using orthogonal methods (e.g., RNA-seq, protein arrays)

  • Include appropriate controls for antibody cross-reactivity

How should researchers interpret contradictory data between BRI3BP mRNA and protein expression levels?

When confronting discrepancies between BRI3BP mRNA and protein expression:

• Biological explanations for discrepancies:

  • Post-transcriptional regulation (miRNAs may target BRI3BP mRNA)

  • Post-translational modifications affecting protein stability

  • Subcellular protein localization differences (nuclear vs. cytoplasmic)

  • Temporal dynamics (protein expression may lag behind mRNA changes)

• Technical considerations:

  • Sample quality differences between RNA and protein analyses

  • Platform-specific biases in transcriptomic vs. proteomic methods

  • Antibody specificity limitations in different applications

  • Sensitivity differences between mRNA and protein detection methods

• Integrated analysis approach:

  • Examine relationships across multiple datasets (METABRIC, TCGA, tissue microarrays)

  • Compare concordance rates between mRNA and protein across different cancer subtypes

  • Analyze correlation with functional endpoints (patient outcome, biological phenotypes)

  • Consider proteogenomic approaches for comprehensive profiling

• Case example from breast cancer research:

  • In METABRIC cohort, high BRI3BP mRNA was associated with ER+ (P<0.001) and PR+ (P=0.008)

  • In contrast, at protein level, high BRI3BP was associated with ER- (P=0.003) and PR- (P=0.002)

  • This suggests complex regulatory mechanisms beyond simple transcription-translation correlation

These contradictions may provide insights into BRI3BP's complex biology and regulatory mechanisms rather than representing technical artifacts .

What emerging technologies show promise for investigating the functional role of BRI3BP in cancer?

Several cutting-edge technologies are advancing BRI3BP research:

• CRISPR-based approaches:

  • CRISPR knockout/knockin models to evaluate BRI3BP necessity and sufficiency

  • CRISPR interference/activation for conditional modulation of BRI3BP expression

  • Base editors for introducing specific BRI3BP mutations

• Advanced imaging technologies:

  • Super-resolution microscopy to visualize BRI3BP subcellular localization

  • Live-cell imaging with tagged BRI3BP to track dynamic interactions

  • Proximity labeling methods (BioID, APEX) to identify BRI3BP interaction partners

• Single-cell technologies:

  • Single-cell RNA-seq to identify BRI3BP expression heterogeneity

  • Single-cell proteomics to correlate BRI3BP with cellular phenotypes

  • Spatial transcriptomics to map BRI3BP expression in tissue microenvironments

• Structural biology approaches:

  • Cryo-EM to determine BRI3BP's structure and interaction domains

  • Hydrogen-deuterium exchange mass spectrometry to map conformational changes

  • AlphaFold2-predicted structures to guide functional studies

• Integrated multi-omics:

  • Proteogenomic integration of BRI3BP expression data

  • Metabolomics to identify downstream effects of BRI3BP modulation

  • Network analysis to position BRI3BP within cancer signaling pathways

How can researchers develop more specific and sensitive BRI3BP detection methods for clinical applications?

To enhance BRI3BP detection for potential clinical applications:

• Antibody engineering approaches:

  • Development of recombinant antibodies with enhanced specificity

  • Creation of bispecific antibodies targeting multiple BRI3BP epitopes

  • Generation of camelid single-domain antibodies (nanobodies) for enhanced tissue penetration

• Novel detection technologies:

  • Digital PCR for absolute quantification of BRI3BP mRNA

  • Ultrasensitive ELISA platforms (Single molecule array, Simoa)

  • Mass spectrometry-based targeted proteomics (parallel reaction monitoring)

  • DNA-barcoded antibody detection systems for enhanced sensitivity

• Circulating biomarker approaches:

  • Develop liquid biopsy approaches for BRI3BP detection in circulation

  • Assess BRI3BP in extracellular vesicles/exosomes from cancer patients

  • Examine BRI3BP autoantibodies as potential cancer biomarkers

• Standardization efforts:

  • Establish reference materials for BRI3BP quantification

  • Develop calibration methods across different platforms

  • Create validation criteria for clinical-grade BRI3BP detection

• Artificial intelligence integration:

  • Machine learning algorithms for automated scoring of BRI3BP IHC

  • Neural networks to integrate BRI3BP with other biomarkers

  • Computer vision approaches for enhanced sensitivity in image-based detection

What are the potential therapeutic implications of targeting BRI3BP in cancer treatment strategies?

Targeting BRI3BP presents several promising therapeutic avenues:

• Direct BRI3BP inhibition strategies:

  • Small molecule inhibitors disrupting BRI3BP protein interactions

  • Peptide mimetics targeting BRI3BP binding interfaces

  • Antisense oligonucleotides or siRNA for BRI3BP knockdown

  • Proteolysis-targeting chimeras (PROTACs) to induce BRI3BP degradation

• Exploiting BRI3BP pathway vulnerabilities:

  • Combined targeting of BRI3BP and K-Ras in K-Ras-driven cancers

  • Synthetic lethality approaches identifying dependencies in BRI3BP-high cancers

  • Modulating BRI3BP's effect on p53 stability and apoptotic pathways

• Biomarker-guided treatment selection:

  • BRI3BP as a predictive marker for response to specific therapies

  • Stratification of breast cancer patients based on BRI3BP expression

  • Monitoring BRI3BP levels during treatment to assess response

• Combination therapy approaches:

  • BRI3BP targeting combined with conventional chemotherapeutics

  • Pairing BRI3BP inhibition with immunotherapies

  • Enhancing apoptotic response through BRI3BP modulation

• Personalized medicine considerations:

  • Different strategies for triple-negative vs. HER2+ breast cancers

  • Molecular profiling to identify patients most likely to benefit

  • Development of companion diagnostics for BRI3BP-targeted therapies