RPL13B Antibody

What is RPL13 and what is its function in cellular biology?

RPL13 (Ribosomal Protein L13) is a critical component of the mammalian ribosome, specifically the 60S large ribosomal subunit. The mammalian ribosome comprises 79 ribosomal proteins and four rRNAs, which combine in equimolar ratios to form the small (40S) and large (60S) subunits . RPL13 plays an essential role in protein synthesis and has been identified as a direct target of the PI3K pathway in promoting cellular growth . Recent research also suggests that RPL13 may function as a plausible candidate tumor suppressor gene, indicating its potential importance beyond its structural role in ribosomes .

The available RPL13 antibodies show consistent cross-reactivity with multiple mammalian species. Based on the validation data, confirmed reactivity includes:

• Human: Positively tested in HeLa cells, SGC-7901 cells, human lung tissue, human colon cancer tissue, human breast tissue, human stomach tissue, and human gastric cancer tissue

• Mouse: Validated through multiple experimental applications

• Rat: Validated with particular confirmation in rat spinal cord and rat brain tissue samples

This multi-species reactivity makes these antibodies versatile tools for comparative studies across mammalian model systems .

How does RPL13 antibody performance compare across different cellular fractionation methods?

• Sequential extraction protocols: Begin with a low-stringency buffer (e.g., 10mM HEPES pH 7.4, 10mM KCl, 0.1% NP-40) for cytoplasmic fractions, followed by nuclear extraction buffer for nuclear-associated ribosomes.

• Polysome profiling preparation: When investigating actively translating ribosomes, cycloheximide treatment (100 μg/ml, 10 minutes) prior to lysis preserves the association of RPL13 with polysomes.

• Detergent selection: While RIPA buffer works for general applications, more specialized analyses may benefit from digitonin-based extraction (50-100 μg/ml) to maintain intact ribosomal complexes.

Western blot validation across fractionation methods consistently identifies RPL13 at the expected molecular weight of 24 kDa, which aligns with both calculated and observed molecular weights reported in the literature .

What methodological considerations should be made when optimizing RPL13 antibody for immunohistochemistry in different tissue types?

Successful immunohistochemical detection of RPL13 across diverse tissue types requires careful optimization of several parameters:

What strategies should be employed when analyzing contradictory RPL13 expression data across different experimental platforms?

When facing contradictory RPL13 expression data across different experimental platforms, implement a systematic analytical approach:

• Antibody validation consistency: Verify that all antibodies used recognize the same epitope region of RPL13. The sequence-verified epitope for reliable antibodies typically corresponds to amino acids 1-211 of human RPL13 (NP_150254.1) .

• Isoform awareness: RPL13 may exhibit tissue-specific isoforms or post-translational modifications. Cross-validate findings using:

  • Multiple antibodies targeting different epitopes

  • RNA expression analysis (RT-qPCR) with isoform-specific primers

  • Mass spectrometry validation of protein identity

• Cross-platform normalization: When comparing between Western blot, IHC, and IF data:

  • Implement identical sample preparation protocols

  • Use consistent loading controls appropriate for each method

  • Quantify relative expression rather than absolute values

  • Apply statistical correction for platform-specific biases

• Multiparametric confirmation: For conclusive resolution of contradictory data, implement orthogonal validation through:

  • CRISPR/siRNA-mediated knockdown to confirm specificity

  • Recombinant protein controls at known concentrations

  • Co-localization with other ribosomal markers in imaging studies

What are the optimal dilution ranges for RPL13 antibodies across different applications?

Proper antibody dilution is critical for balancing specific signal detection with background minimization. Based on extensive validation data, the recommended dilution ranges for RPL13 antibodies by application are:

For all applications, preliminary titration experiments are strongly recommended to determine optimal conditions for specific experimental systems and sample types .

How should researchers approach fixation and permeabilization protocols when using RPL13 antibodies for immunofluorescence?

Effective immunofluorescence with RPL13 antibodies requires careful consideration of fixation and permeabilization protocols:

• Fixation optimization:

  • Paraformaldehyde (PFA): 4% PFA for 10-15 minutes at room temperature preserves epitope recognition while maintaining cellular architecture

  • Methanol: Ice-cold 100% methanol (5 minutes at -20°C) offers superior detection of nucleolar-associated RPL13

  • Combination approach: For difficult samples, sequential fixation with 2% PFA (10 minutes) followed by methanol (-20°C, 5 minutes) may enhance signal

• Permeabilization strategies:

  • Standard: 0.1-0.25% Triton X-100 (10 minutes) works for most cell types

  • Gentle: 0.05% saponin is preferable for preserving delicate ribosomal structures

  • Nuclear-focused: 0.5% Triton X-100 with extended incubation (15 minutes) enhances nucleolar signal

• Blocking considerations:

  • For cytoplasmic RPL13 detection: 3-5% BSA in PBS (1 hour)

  • For nucleolar RPL13 detection: Add 5% normal serum from secondary antibody host species to blocking buffer

  • Background reduction: Include 0.1% Tween-20 in all blocking and antibody dilution buffers

• Protocol adjustment by cell type:

  • Epithelial cells: Standard protocols work effectively

  • Neurons: Extended permeabilization (15-20 minutes) improves detection

  • Primary tissues: Increase antibody concentration to 1:50 and extend incubation to overnight at 4°C

What controls should be implemented when evaluating RPL13 antibody specificity in experimental workflows?

Comprehensive evaluation of RPL13 antibody specificity requires implementation of multiple control strategies:

• Positive controls:

  • Cell lines with confirmed RPL13 expression (e.g., HeLa, SGC-7901)

  • Tissues with known high expression (human lung, colon cancer tissue)

  • Recombinant RPL13 protein at defined concentrations

• Negative controls:

  • Primary antibody omission (secondary antibody only)

  • Isotype control using matched rabbit IgG at equivalent concentration

  • Pre-incubation of antibody with immunizing peptide (blocking peptide)

  • CRISPR/siRNA RPL13 knockdown samples (recognizing complete knockdown may not be viable)

• Validation across techniques:

  • Molecular weight confirmation (24 kDa) by Western blot

  • Expected subcellular localization pattern in IF/ICC

  • Correlation with RNA expression data

• Cross-reactivity assessment:

  • Testing across multiple species when working in non-human models

  • Evaluating potential cross-reactivity with closely related ribosomal proteins

What are the common troubleshooting strategies for inconsistent RPL13 Western blot results?

Inconsistent Western blot results with RPL13 antibodies often stem from several identifiable factors. The following troubleshooting strategy addresses common issues:

• Multiple bands or unexpected molecular weight:

  • Expected band: Clear 24 kDa band corresponding to RPL13

  • Issue: Degradation or post-translational modifications

  • Solution: Add protease inhibitors freshly to lysis buffer, avoid freeze-thaw cycles, and consider phosphatase inhibitors

• Weak or absent signal:

  • Primary cause: Insufficient protein loading or antibody concentration

  • Solution: Increase protein load (25-50 μg recommended) , reduce antibody dilution to 1:500 , and extend primary antibody incubation to overnight at 4°C

• High background:

  • Primary cause: Insufficient blocking or washing

  • Solution: Increase blocking time (60 minutes), use 5% non-fat dry milk in TBST , and extend wash steps (4 x 10 minutes)

• Inconsistent results between experiments:

  • Primary cause: Variable sample preparation or transfer efficiency

  • Solution: Standardize lysate preparation protocol, implement loading control normalization, and validate transfer with reversible total protein stain

• Sample-specific considerations:

  • For challenging samples, one-step Western blot methods have shown success at 1:1000 dilution ratio

  • HRP-conjugated secondary antibody at 1:4000-1:10000 provides optimal signal-to-noise ratio

How can researchers optimize immunohistochemical detection of RPL13 in archival FFPE samples?

Archival formalin-fixed paraffin-embedded (FFPE) samples present unique challenges for RPL13 detection. The following optimization protocol enhances detection in these challenging specimens:

• Enhanced antigen retrieval:

  • Primary recommendation: High-temperature (95-98°C) retrieval in TE buffer (pH 9.0) for 20-30 minutes

  • Alternative: Pressure cooker-based retrieval in citrate buffer (pH 6.0) for 10 minutes

  • For highly crosslinked samples: Sequential retrieval with citrate buffer followed by TE buffer

• Signal amplification strategies:

  • Implement biotin-tyramide amplification system for low-expression samples

  • Extend primary antibody incubation to overnight at 4°C at dilution of 1:20-1:50

  • Consider polymer-based detection systems with extended development times

• Background reduction:

  • Incorporate dual blocking: 3% hydrogen peroxide (10 minutes) followed by protein block (30 minutes)

  • Add 0.1% Triton X-100 to antibody diluent to enhance penetration

  • Include background-reducing agents (0.1% BSA, 0.5% non-fat milk) in antibody dilution buffer

• Validated tissue-specific protocols:

  • Human colon cancer tissue: TE buffer (pH 9.0) retrieval with 1:50 antibody dilution

  • Human breast tissue: Standard protocol at 1:100 dilution

  • Human gastric cancer: Standard protocol at 1:100 dilution

What protocol modifications are necessary when using RPL13 antibodies for co-immunoprecipitation of ribosomal complexes?

Co-immunoprecipitation (Co-IP) of RPL13 and associated ribosomal complexes requires specialized protocols to maintain complex integrity:

• Optimized lysis conditions:

  • Buffer composition: 20 mM HEPES pH 7.4, 150 mM KCl, 5 mM MgCl₂, 0.5% NP-40, 1 mM DTT, protease/phosphatase inhibitors

  • Lysis temperature: Maintain samples at 4°C throughout processing

  • RNase inhibitors: Include RNasin or SUPERase- In (40 U/mL) to preserve RNA-dependent interactions

• IP optimization:

  • Antibody amount: 2-4 μg of RPL13 antibody per 1-3 mg of total protein lysate

  • Pre-clearing: Incubate lysate with Protein A/G beads (1 hour, 4°C) before antibody addition

  • Antibody binding: Overnight incubation at 4°C with gentle rotation

  • Bead selection: Protein A/G magnetic beads provide higher purity than agarose alternatives

• Washing considerations:

  • Salt concentration: Graduated washes (150 mM → 300 mM → 150 mM KCl) to remove non-specific interactions

  • Detergent: Decrease NP-40 concentration in wash buffers (0.1-0.05%)

  • Final wash: Use detergent-free buffer to remove contaminating detergent

• Elution strategies:

  • For protein analysis: Standard SDS elution buffer at 95°C (5 minutes)

  • For functional complexes: Competitive elution with RPL13 peptide (100 μg/mL, 30 minutes at 25°C)

  • For RNA analysis: TRIzol-based extraction directly from beads

• Validation approaches:

  • Confirming RPL13 pull-down by Western blot at 24 kDa

  • Evaluating co-IP of known ribosomal partners

  • Assessing ribosomal RNA co-precipitation by RT-qPCR

How can RPL13 antibodies be incorporated into spatial transcriptomics workflows?

RPL13 antibodies can serve as valuable tools in emerging spatial transcriptomics applications through several innovative approaches:

• Multiplex immunofluorescence integration:

  • RPL13 antibody (1:100 dilution) can be used alongside RNA-FISH probes to correlate protein localization with active translation sites

  • Sequential antibody labeling using tyramide signal amplification allows multiplexing with other ribosomal components

  • Compatible with standard IF protocols using paraformaldehyde fixation

• In situ proximity ligation adaptation:

  • RPL13 antibody can be paired with antibodies against translation factors to visualize active translation complexes

  • Requires optimization of antibody dilution to 1:50-1:100 range

  • Most effective with dual primary antibodies from different host species

• Single-cell spatial proteomic applications:

  • RPL13 serves as an effective normalization marker for ribosomal content

  • Protocol modification: Gentle cell permeabilization (0.1% saponin) preserves spatial architecture

  • Dilution adjustment to 1:50 recommended for single-cell sensitivity

• Tissue section optimization:

  • For FFPE tissues: Antigen retrieval as described in section 4.2 is critical

  • For fresh-frozen tissues: Light fixation (2% PFA, 10 minutes) followed by gentle permeabilization

  • Background reduction: Extended blocking (2 hours) with 5% normal serum from secondary antibody host species

What considerations should be made when integrating RPL13 antibodies into high-content screening workflows?

Integration of RPL13 antibodies into high-content screening platforms requires specific optimization strategies:

• Assay miniaturization:

  • Validated dilution for 96/384-well formats: 1:100 for immunofluorescence applications

  • Primary antibody volume can be reduced to 20-30 μL per well

  • Incubation time can be shortened to 1-2 hours at room temperature with gentle orbital shaking

• Automation compatibility:

  • Fixation: 4% PFA (10 minutes) followed by permeabilization with 0.1% Triton X-100 (10 minutes)

  • Blocking: 3% BSA in PBS (30 minutes) is suitable for automated dispensing systems

  • Washing: Minimum 3 washes with PBS containing 0.05% Tween-20

• Multiplexed detection strategies:

  • RPL13 antibody performs well in combination with cell cycle markers

  • Nuclear counterstain: DAPI or Hoechst 33342 at standard concentrations

  • Compatible secondary antibodies: Fluorophore-conjugated anti-rabbit IgG (Alexa Fluor series)

• Image analysis parameters:

  • Primary cellular compartment: Cytoplasm with nucleolar enrichment

  • Recommended segmentation approach: Cytoplasmic mask expanded from nuclear segmentation

  • Quantification metrics: Integrated intensity, texture features, and subcellular distribution patterns

• Positive controls for screening:

  • Translation inhibitors (cycloheximide, puromycin) alter RPL13 distribution

  • mTOR pathway modulators (rapamycin, Torin1) affect RPL13 expression levels

  • Include control wells on each plate for normalization