RPL23B Antibody

What is RPL23 and why is it a significant research target?

RPL23 (Ribosomal Protein L23) is a component of the 60S large ribosomal subunit involved in protein synthesis. This 15 kDa protein (140 amino acids) plays crucial roles beyond ribosome function, including regulation of cellular apoptosis, cell cycle progression, and signal transduction pathways. Its dysregulation has been implicated in various pathologies, including cancer progression and neurodegenerative diseases, making it a valuable research target .

What applications are RPL23 antibodies validated for in research settings?

RPL23 antibodies have been validated for multiple research applications, including:

• Western Blot (WB): Typically at dilutions of 1:500-1:4000

• Immunohistochemistry (IHC): Generally at dilutions of 1:50-1:500

• Immunoprecipitation (IP): Using 0.5-4.0 μg antibody per 1.0-3.0 mg of protein lysate

• Immunofluorescence/Immunocytochemistry (IF/ICC): Usually at dilutions of 1:50-1:200

• RNA Immunoprecipitation (RIP): For detecting RNA-protein interactions

• ELISA: For quantitative detection

What species reactivity do commercially available RPL23 antibodies demonstrate?

Most RPL23 antibodies show cross-reactivity with human, mouse, and rat samples. This is consistent across multiple antibody manufacturers due to the high conservation of RPL23 sequence across mammalian species. Positive reactivity has been confirmed in multiple cell lines including HeLa, HEK-293T, Jurkat, BxPC-3, PC-3, NIH/3T3, and tissue samples from human and mouse brain .

How can I validate RPL23 knockdown efficiency in functional studies?

For validating RPL23 knockdown:

• Quantitative RT-PCR: Measure RPL23 mRNA levels using specific primers (normalization to housekeeping genes required)

• Western blot analysis: Detect protein levels using validated antibodies (1:500-1:2000 dilution)

• Phenotypic confirmation: Assess established cellular consequences of RPL23 depletion, including:

  • Decreased cellular viability

  • Increased apoptosis

  • G1-S cell cycle arrest

  • Altered expression of Miz-1, p21^Cip1, and p15^Ink4b

As demonstrated in multiple studies, successful RPL23 knockdown typically results in 70-90% reduction in both mRNA and protein levels when compared to control conditions .

What are the optimal conditions for detecting newly synthesized RPL23 in models of neurodegenerative disease?

To detect newly synthesized RPL23 in neurodegenerative disease models, researchers have successfully employed the FUNCAT-proximal ligation assay (FUNCAT-PLA) technique with the following methodology:

• Label newly synthesized proteins with AHA (azidohomoalanine)

• Biotinylate AHA-labeled proteins using DBCO-biotin on tissue sections

• Incubate sections with anti-biotin and anti-RPL23 primary antibodies

• Apply PLA secondary antibodies to develop signal when primary antibodies are in proximity (<40 nm)

• Quantify PLA signal in specific neuronal populations of interest

This technique has revealed significant decreases in RPL23 synthesis in mouse models of tauopathy, with more pronounced effects at later disease stages (5 months compared to 2 months) .

How can I optimize RPL23 antibody protocols for detecting protein-RNA interactions?

For investigating RPL23-RNA interactions, RNA immunoprecipitation (RIP) can be optimized with these steps:

• Cross-link protein-RNA complexes using formaldehyde (1% for 10 minutes at room temperature)

• Lyse cells in RIPA buffer supplemented with RNase inhibitors

• Pre-clear lysate with Protein A/G beads

• Immunoprecipitate using 4-6 μg of RPL23 antibody per 1-2 mg of lysate (overnight at 4°C)

• Wash stringently while preserving RNA integrity

• Reverse cross-links and purify RNA

• Perform RT-PCR or RNA-seq to identify bound transcripts

This approach has been successfully used to demonstrate that RPL23 binds to the 3'UTR of MMP9 mRNA, enhancing its stability and promoting metastasis in hepatocellular carcinoma .

How is RPL23 expression altered in cancer models, and how can antibodies help quantify these changes?

RPL23 expression has distinct patterns across cancer types:

For quantification, researchers typically use immunohistochemistry scoring systems (0-3+) for tissue samples and normalized band intensity analysis for Western blots, with RPL23 levels showing significant correlation with clinical parameters including tumor grade, lymphatic metastasis, and chemotherapy resistance .

What is the relationship between RPL23 and neurodegenerative tauopathies, and how is this best studied experimentally?

In neurodegenerative tauopathies:

• RPL23 synthesis is significantly decreased in mouse models of tauopathy (K3 and rTg4510)

• The decrease in RPL23 synthesis correlates with disease progression

• Total RPL23 abundance shows an inverse correlation with tau phosphorylation levels (AT8 tau)

• Similar alterations have been observed in human FTD (frontotemporal dementia) brain samples

Experimental approaches include:

• FUNCAT-PLA for detecting newly synthesized RPL23

• Co-immunostaining with AT8 (phospho-tau) and RPL23 antibodies

• Pearson's correlation analysis between RPL23 levels and tau phosphorylation

• Quantitative analysis of RPL23 in age-matched neurodegenerative disease models and controls

These studies suggest that tau-mediated inhibition of ribosomal protein synthesis increases with disease progression, potentially contributing to neurodegeneration .

How does RPL23 contribute to chemoresistance mechanisms, and what experimental approaches can elucidate these pathways?

RPL23's role in chemoresistance can be investigated through these approaches:

• Comparative expression analysis:

  • Western blot and qRT-PCR comparing RPL23 levels in cisplatin-sensitive vs. resistant cell lines

  • IHC staining of patient samples categorized by treatment response

• Functional validation:

  • siRNA or shRNA knockdown of RPL23 in resistant cells followed by:

    • Cell viability assays with cisplatin treatment

    • Apoptosis quantification (Annexin V/PI staining)

    • Cell cycle analysis

    • Invasion and migration assays

• Mechanistic investigation:

  • EMT marker assessment (E-cadherin, N-cadherin, vimentin) by Western blot

  • RPL23 overexpression rescue experiments in knockdown models

Studies have demonstrated that RPL23 knockdown can reverse cisplatin resistance in epithelial ovarian carcinoma by inhibiting epithelial-mesenchymal transition, suggesting RPL23 as a potential therapeutic target for platinum-resistant cancers .

What are the common pitfalls in RPL23 immunohistochemistry, and how can they be addressed?

Common challenges in RPL23 immunohistochemistry include:

• Variable staining intensity:

  • Solution: Optimize antigen retrieval with TE buffer pH 9.0 (alternatively, citrate buffer pH 6.0)

  • Titrate antibody concentration between 1:50-1:500 for optimal signal-to-noise ratio

• High background:

  • Solution: Include additional blocking steps with 5% BSA or normal serum

  • Increase washing duration and number of washes

• Subcellular localization discrepancies:

  • Solution: Use confocal microscopy to accurately determine localization

  • RPL23 shows multiple cellular localizations (cytoplasm, cytosol, nucleolus, nucleoplasm)

• Cross-reactivity concerns:

  • Solution: Include appropriate controls (isotype control, RPL23 knockdown samples)

  • Validate with a second independent RPL23 antibody targeting a different epitope

How can I ensure reliable quantification of RPL23 protein levels when comparing normal and disease states?

For reliable RPL23 quantification across normal and disease states:

• Sample preparation standardization:

  • Use consistent lysis buffers (RIPA buffer with protease inhibitors)

  • Standardize protein quantification methods (BCA/Bradford)

• Loading controls selection:

  • Choose appropriate loading controls based on the disease context

  • For cancer studies, β-actin may be suitable

  • For neurodegenerative studies, consider multiple loading controls (GAPDH and β-tubulin)

• Technical considerations:

  • Include internal reference samples across multiple blots

  • Use fluorescent Western blot systems for greater dynamic range

  • Perform biological triplicates and technical duplicates minimum

• Analytical approaches:

  • Normalize RPL23 signal to loading control

  • For IHC, use digital image analysis with standardized algorithms

  • Apply appropriate statistical tests (Mann-Whitney for non-parametric data)

What strategies can address non-specific binding when using RPL23 antibodies in complex tissue samples?

To minimize non-specific binding in complex tissue samples:

• Pre-adsorption steps:

  • Pre-incubate antibody with recombinant RPL23 protein to evaluate specificity

  • Use control peptides for antibody pre-adsorption when available

• Blocking optimization:

  • Extended blocking (2+ hours) with 5-10% normal serum from the species of secondary antibody

  • Addition of 0.1-0.3% Triton X-100 for better antibody penetration

• Antibody dilution and incubation:

  • Test broader dilution ranges (1:50-1:1000)

  • Extend primary antibody incubation to overnight at 4°C

  • Consider using antibody diluents with background-reducing components

• Validation controls:

  • Include tissue from RPL23 knockdown models as negative controls

  • Use multiple antibodies targeting different RPL23 epitopes

  • Perform peptide competition assays to confirm specificity

How can RPL23 antibodies be employed to investigate the role of RPL23 in the p53 tumor suppression pathway?

RPL23 antibodies can effectively investigate the RPL23-p53 regulatory axis through:

• Co-immunoprecipitation studies:

  • Use RPL23 antibodies to pull down protein complexes

  • Probe for MDM2 and p53 interactions

  • Analyze how oncogenic signals (RAS, MYC) alter these interactions

• Chromatin immunoprecipitation (ChIP):

  • Determine if RPL23 associates with specific genomic regions

  • Investigate potential transcriptional regulatory roles

• Stress response experiments:

  • Track RPL23-MDM2-p53 dynamics following ribosomal stress

  • Monitor subcellular localization changes using immunofluorescence

• Mutant analysis:

  • Compare RPL23 interaction patterns with wild-type vs. MDM2 C305F mutant

  • Investigate how mutations affect p53 activation

These approaches have revealed that RPL23 links oncogenic RAS signaling to p53-mediated tumor suppression, with RAS overexpression increasing RPL23 expression through MEK and PI3K signaling pathways in a p53-independent manner .

What experimental design is optimal for investigating RPL23's role in regulating ribosome biogenesis under stress conditions?

To investigate RPL23's role in ribosome biogenesis under stress:

• Polysome profiling:

  • Compare polysome profiles between control and RPL23-depleted cells

  • Analyze shifts in monosome/polysome ratios under various stressors

  • Use sucrose gradient fractionation followed by Western blot with RPL23 antibodies

• rRNA processing analysis:

  • Pulse-chase labeling with 32P-orthophosphate

  • Northern blot analysis of pre-rRNA and mature rRNA species

  • qRT-PCR of pre-rRNA processing intermediates

• Nucleolar stress assessment:

  • Immunofluorescence co-staining of RPL23 with nucleolar markers

  • Live cell imaging with fluorescently tagged RPL23

  • Analysis of nucleolar morphology changes

• Translational output measurement:

  • Puromycin incorporation assays under stress conditions

  • SUnSET (Surface Sensing of Translation) methodology

  • Mass spectrometry analysis of newly synthesized proteins

These approaches can reveal how RPL23 contributes to maintaining translational capacity during cellular stress, with implications for understanding disease mechanisms where proteostasis is compromised .