lrp2bp Antibody

What is LRP2BP and what cellular functions does it serve?

LRP2BP (LRP2 Binding Protein) is a 347 amino acid protein with an observed molecular weight of approximately 45 kDa (slightly higher than its calculated weight of 40 kDa) . This protein acts primarily as an adapter that regulates LRP2 (Low-density lipoprotein Receptor-related Protein 2, also known as Megalin) function . LRP2 itself is a substantial protein of approximately 522 kilodaltons that functions in various endocytic and signaling pathways .

The binding interaction between LRP2BP and LRP2 suggests involvement in receptor-mediated endocytosis pathways, potentially affecting protein trafficking and cellular uptake mechanisms. Understanding this interaction is crucial for research in kidney function, neurodevelopment, and certain pathological conditions where LRP2 signaling is implicated.

What species reactivity is available for commercial LRP2BP antibodies?

Research-grade LRP2BP antibodies demonstrate varied cross-reactivity profiles depending on the specific reagent. Based on available data, the following species reactivity has been validated:

When selecting an antibody for cross-species applications, sequence homology should be considered. For example, the ABIN2775460 antibody targets a middle region epitope with predicted reactivity across multiple species: Cow (100%), Dog (100%), Guinea Pig (93%), Horse (100%), Human (100%), Mouse (100%), Pig (100%), Rabbit (100%), Rat (100%), and Zebrafish (92%) .

What validated applications exist for LRP2BP antibodies?

Current research-grade LRP2BP antibodies have been validated for several experimental applications:

Validation has been performed using specific positive controls, including A549 cells, Jurkat cells, and rat lung tissue for Western blot applications, and human cerebellum tissue for immunohistochemistry .

What are the optimal antigen retrieval methods for LRP2BP immunohistochemistry?

For successful LRP2BP detection in formalin-fixed, paraffin-embedded tissue sections, proper antigen retrieval is critical. Based on validated protocols, the following methods are recommended:

• Primary recommendation: TE buffer at pH 9.0

• Alternative method: Citrate buffer at pH 6.0

The higher pH TE buffer (pH 9.0) often provides superior epitope unmasking for LRP2BP detection, particularly when using the 25783-1-AP antibody. This is consistent with the general observation that certain nuclear and membrane-associated proteins demonstrate enhanced antigen retrieval at alkaline pH. Temperature and duration of antigen retrieval should be optimized for each tissue type, with typical protocols involving 95-100°C for 10-20 minutes.

How should researchers address unexpected molecular weight observations for LRP2BP?

While the calculated molecular weight of LRP2BP is 40 kDa based on its 347 amino acid sequence, the observed molecular weight in SDS-PAGE/Western blot is approximately 45 kDa . This 5 kDa difference should not be considered experimental error, but rather may reflect:

• Post-translational modifications (phosphorylation, glycosylation)

• The presence of hydrophobic regions affecting migration patterns

• Incomplete denaturation during sample preparation

When validating a new LRP2BP antibody, researchers should anticipate detection around 45 kDa rather than the theoretical 40 kDa. If significantly different molecular weights are observed, consider:

• Running known positive controls (A549 cells, Jurkat cells, or rat lung tissue)

• Employing reducing and non-reducing conditions to assess structural influences

• Using phosphatase treatment to determine if phosphorylation contributes to the shift

What strategies can enhance specificity when detecting LRP2BP in complex samples?

Maximizing specific detection while minimizing background requires several optimizations:

• Antibody dilution titration: Test dilutions between 1:500-1:2000 for WB and 1:50-1:500 for IHC to determine optimal signal-to-noise ratio

• Blocking optimization: Use 5% non-fat milk or BSA in TBST, matching the blocking agent to the diluent used for primary antibody

• Enhanced washing: Implement at least 3 wash steps of 5-10 minutes each with TBST after both primary and secondary antibody incubations

• Positive and negative controls: Always include validated positive controls (A549 cells, Jurkat cells, human cerebellum) and appropriate negative controls (primary antibody omission, isotype controls)

• Validation with multiple antibodies: When possible, confirm results using antibodies targeting different epitopes of LRP2BP

How should researchers design co-immunoprecipitation experiments to study LRP2BP-LRP2 interactions?

Given that LRP2BP functions as an adapter protein regulating LRP2 , investigating their physical interaction requires carefully designed co-immunoprecipitation (Co-IP) experiments:

• Lysis buffer selection: Use mild, non-denaturing lysis buffers (e.g., 1% NP-40 or 0.5% Triton X-100 in PBS with protease inhibitors) to preserve protein-protein interactions

• Antibody selection strategy:

  • Primary approach: Immunoprecipitate with anti-LRP2 antibody and probe for LRP2BP

  • Reverse approach: Immunoprecipitate with anti-LRP2BP antibody and probe for LRP2

  • Both approaches should yield complementary results if the interaction is specific

• Control experiments:

  • IgG control: Perform parallel IP with isotype-matched non-specific IgG

  • Input control: Always run 5-10% of pre-IP lysate to confirm target protein presence

  • Competitive inhibition: Consider using recombinant LRP2BP protein to establish specificity

• Detection system: Given the significant size difference between LRP2 (522 kDa) and LRP2BP (45 kDa), use an appropriate gel system that resolves both molecular weight ranges effectively.

What are the key considerations for quantifying LRP2BP expression in tissue samples?

Accurate quantification of LRP2BP in complex tissues requires careful methodological considerations:

• Sample preparation standardization:

  • For western blot: Standardize protein extraction methods and ensure equal loading (20-50 μg total protein)

  • For IHC: Use consistent fixation times and tissue processing

• Normalization strategy:

  • Western blot: Normalize to housekeeping proteins (β-actin, GAPDH, or tubulin)

  • IHC: Use appropriate scoring systems (H-score, Allred score) incorporating both staining intensity and percentage of positive cells

• Analysis parameters for IHC:

  • Score intensity on scale (0-3+)

  • Record percent positive cells

  • Note subcellular localization patterns

  • Consider automated image analysis for greater objectivity

• Statistical approaches:

  • Perform technical triplicates at minimum

  • Use appropriate statistical tests based on data distribution

  • Include sufficient biological replicates (n≥3) to account for biological variability

How can researchers troubleshoot weak or absent LRP2BP signal in Western blots?

When encountering poor LRP2BP detection in Western blot experiments, consider this systematic troubleshooting approach:

• Sample preparation:

  • Ensure complete lysis (consider stronger lysis buffers with SDS)

  • Add fresh protease inhibitors to prevent degradation

  • Avoid repeated freeze-thaw cycles of protein samples

• Transfer optimization:

  • For the 45 kDa LRP2BP protein, use PVDF membranes and semi-dry or wet transfer

  • Transfer at lower voltage (30V) for longer time (2 hours) to ensure complete transfer

  • Verify transfer efficiency with Ponceau S staining

• Antibody related factors:

  • Increase antibody concentration (try 1:500 dilution if using 1:2000)

  • Extend primary antibody incubation to overnight at 4°C

  • Use validated positive controls (A549 cells, Jurkat cells, rat lung tissue)

  • Check antibody expiration and storage conditions (maintain at -20°C with 50% glycerol)

• Detection system:

  • Use enhanced chemiluminescence (ECL) with extended exposure times

  • Consider signal enhancement systems if standard ECL is insufficient

  • For fluorescent detection, optimize gain settings

What controls should be included when validating a new lot of LRP2BP antibody?

Rigorous validation of new antibody lots is crucial for experimental reproducibility:

• Essential positive controls:

  • Western blot: A549 cells, Jurkat cells, rat lung tissue

  • IHC: Human cerebellum tissue

• Specificity controls:

  • Pre-absorption with immunizing peptide (if available)

  • Knockdown/knockout cell lines or tissues (siRNA, CRISPR)

  • Panel of cell lines with variable LRP2BP expression

• Technical validation tests:

  • Dilution series to establish optimal concentration

  • Comparison with previous lot performance (side-by-side testing)

  • Molecular weight verification (expecting 45 kDa band)

• Documentation requirements:

  • Record lot number, dilution, incubation conditions

  • Retain images of control experiments

  • Note any performance differences compared to previous lots

What are the recommended protocols for dual immunofluorescence studies involving LRP2BP?

To investigate LRP2BP co-localization with other proteins (particularly LRP2) using dual immunofluorescence:

• Sample preparation considerations:

  • Use freshly fixed tissues/cells (4% PFA, 10-20 minutes)

  • For formalin-fixed paraffin sections, perform thorough antigen retrieval with TE buffer pH 9.0

  • Permeabilize with 0.1-0.3% Triton X-100 for intracellular epitopes

• Antibody selection and sequencing:

  • Choose antibodies raised in different host species (e.g., rabbit anti-LRP2BP with mouse anti-LRP2)

  • If using same-species antibodies, sequential immunostaining with direct labeling of the first primary antibody is recommended

• Optimization parameters:

  • Dilution: Start with 1:100 for immunofluorescence (generally higher concentration than IHC)

  • Blocking: 5-10% normal serum matching the host of secondary antibodies

  • Incubation: Overnight at 4°C for primary antibodies

• Controls:

  • Single-stained controls to verify absence of bleed-through

  • Secondary-only controls to assess background

  • Absorption controls with immunizing peptides where available

How should researchers approach tissue-specific optimization of LRP2BP immunohistochemistry?

Different tissues require specific optimization strategies for optimal LRP2BP detection:

• Tissue-specific antigen retrieval:

  • Neural tissues (cerebellum): TE buffer pH 9.0, 20 minutes at 95°C

  • Kidney tissue: Test both TE buffer pH 9.0 and citrate buffer pH 6.0

  • Formalin-fixed tissues: May require extended retrieval (20-30 minutes)

• Background reduction strategies:

  • Kidney tissue: Add 0.3% H₂O₂ block for 10 minutes before antibody incubation

  • High-fat tissues: Add additional detergent (0.1% Tween-20) to washing buffers

  • Tissues with high endogenous biotin: Use avidin-biotin blocking if using biotin-based detection

• Signal amplification options:

  • Low expression tissues: Consider tyramide signal amplification

  • Highly autofluorescent tissues: Use enzyme-based detection instead of fluorescence

  • FFPE tissues: Longer primary antibody incubation (overnight at 4°C)

• Validation approach:

  • Start with known positive control tissues (human cerebellum)

  • Compare multiple fixation times when establishing new protocols

  • Document tissue-specific optimizations for laboratory reference

How should researchers interpret unexpected subcellular localization patterns of LRP2BP?

While LRP2BP is expected to associate with LRP2/megalin at the plasma membrane and in endocytic compartments, unexpected localization patterns may be observed. Consider the following interpretation framework:

• Common subcellular patterns and interpretations:

  • Membrane-associated + cytoplasmic vesicular: Expected pattern reflecting functional association with LRP2

  • Nuclear localization: May indicate alternative functions or antibody cross-reactivity

  • Golgi-enriched: Could reflect biosynthetic trafficking of newly synthesized protein

  • Diffuse cytoplasmic: Potential overexpression artifact or dissociation from membrane structures

• Verification approaches:

  • Subcellular fractionation followed by Western blot

  • Co-localization with organelle markers (e.g., Na⁺/K⁺ ATPase for plasma membrane, EEA1 for early endosomes)

  • Multiple antibodies targeting different LRP2BP epitopes

  • Correlation with LRP2/megalin localization

• Biological significance assessment:

  • Correlate localization patterns with cellular function

  • Consider pathological conditions that might alter trafficking

  • Investigate potential regulatory post-translational modifications

What considerations are important when comparing LRP2BP expression across different experimental models?

When comparing LRP2BP expression between different experimental systems (e.g., cell lines vs. primary tissues, human vs. animal models), consider these critical factors:

• Species-specific considerations:

  • Use antibodies validated for the species being compared

  • Consider species differences in LRP2BP sequence and function

  • Expected molecular weight may vary slightly between species

• Expression baseline establishment:

  • Different tissues have variable baseline expression

  • Normalize to appropriate housekeeping genes/proteins for each tissue type

  • Consider relative expression rather than absolute values when comparing across models

• Technical standardization:

  • Use identical sample preparation, antibody lots, and detection methods

  • Process and analyze all comparative samples simultaneously

  • Include inter-experimental calibration samples

• Data interpretation framework:

  • Statistical analysis appropriate for multiple group comparisons

  • Consider biological significance beyond statistical significance

  • Account for model-specific confounding factors

What are promising research applications for LRP2BP antibodies beyond conventional techniques?

As research techniques evolve, LRP2BP antibodies may be valuable in several emerging applications:

• Proximity ligation assay (PLA) applications:

  • Detecting in situ interactions between LRP2BP and LRP2

  • Quantifying protein-protein interactions in different cellular compartments

  • Studying co-localization dynamics under various stimuli

• ChIP-seq related approaches:

  • Investigating potential nuclear roles of LRP2BP

  • Studying chromatin associations if nuclear localization is confirmed

  • Combining with RNA-seq to correlate with gene expression profiles

• Super-resolution microscopy:

  • Nanoscale localization of LRP2BP in membrane microdomains

  • Co-localization with endocytic machinery components

  • Tracking of LRP2BP trafficking in live cells with tagged antibodies

• Therapeutic and diagnostic development:

  • Antibody-drug conjugates targeting LRP2BP-expressing cells

  • Diagnostic imaging applications in tissues with altered LRP2BP expression

  • Potential for companion diagnostics in personalized medicine approaches