RPS19BP1 Antibody

What is RPS19BP1 and what cellular functions does it mediate?

RPS19BP1 is a 136 amino acid protein that primarily localizes to the nucleolus. It functions as an active regulator of SIRT1 (silencing information regulator 2 related enzymes 1), a protein deacetylase that controls the transcription of numerous target substrates, including p53 . The gene encoding RPS19BP1 maps to human chromosome 22, which houses over 500 genes and is the second smallest human chromosome . RPS19BP1 has been implicated in regulating cell proliferation, migration, and apoptosis through its interaction with key signaling pathways, particularly the p53 pathway. It enhances the SIRT1-mediated deacetylation of p53 and inhibits p53-induced transcriptional activity, thereby influencing cellular responses to stress and DNA damage .

What are the reliable methods for detecting RPS19BP1 in experimental samples?

Detection of RPS19BP1 in experimental samples can be achieved through several validated methods:

• Western Blot (WB): The most common application, with recommended dilutions ranging from 1:500 to 1:2000 . This technique allows for protein quantification and molecular weight verification (~15 kDa theoretical, observed at ~20 kDa) .

• Immunofluorescence (IF): Enables subcellular localization studies with recommended dilutions of 1:50 to 1:200 . This method is particularly useful for confirming the nucleolar localization of RPS19BP1.

• Immunoprecipitation (IP): Effective for studying protein-protein interactions with recommended dilutions of 1:50 to 1:200 .

• Immunohistochemistry (IHC): Used for tissue expression analysis with recommended dilutions of 1:200 to 1:500 .

Each method requires proper optimization depending on the specific antibody and sample types being used.

What is the optimal storage and handling protocol for RPS19BP1 antibodies?

For maximum antibody stability and performance, RPS19BP1 antibodies should be stored following these guidelines:

• Short-term storage (up to one month): 4°C is sufficient .

• Long-term storage: -20°C is recommended to maintain antibody integrity .

• Avoid repeated freeze-thaw cycles as they can degrade antibody quality and reduce binding efficacy .

• RPS19BP1 antibodies are typically supplied in PBS with 0.02% sodium azide and 50% glycerol at pH 7.2-7.3 .

• When shipping is required, wet ice conditions are appropriate .

For handling, it is advisable to centrifuge the vial before opening to ensure complete recovery of contents, especially after shipping or long-term storage .

How does RPS19BP1 interact with the p53 signaling pathway?

RPS19BP1 plays a crucial role in regulating p53 activity through multiple mechanisms:

• SIRT1 Regulation: RPS19BP1 functions as an active regulator of SIRT1, a protein deacetylase that controls the transcription of numerous target substrates, including p53 .

• p53 Deacetylation: Through its interaction with SIRT1, RPS19BP1 promotes the deacetylation of p53, which reduces p53's transcriptional activity and its ability to induce cell cycle arrest and apoptosis .

• Cancer Progression: In prostate cancer (PCa), RPS19BP1 forms a co-regulatory axis with LINC00106 that inhibits p53 activity, promoting proliferation and migration of PCa cells .

• Cell Cycle Regulation: By modulating p53 activity, RPS19BP1 influences cell cycle progression and bypass of p53-dependent cell cycle arrest mechanisms .

Experimental evidence shows that knockdown of RPS19BP1 significantly increases p53 activity in cancer cell lines, confirming its inhibitory effect on p53 function .

What experimental approaches are recommended for studying RPS19BP1-RNA interactions?

Based on published methodologies, the following approaches are effective for studying RPS19BP1-RNA interactions:

• RNA-binding protein immunoprecipitation (RIP):

  • Use Magna RIP kit or equivalent

  • Lyse cells with RIP lysis buffer

  • Incubate cell extracts with magnetic beads coupled with specific antibodies or IgG (as control) at 4°C for 12 hours

  • Wash magnetic beads and treat with proteinase-K to eliminate proteins

  • Purify RNA and perform RT-qPCR analysis to detect specific interactions

• RNA pull-down assay:

  • Label RNA of interest with biotin using in vitro transcription

  • Incubate with cell protein lysates to form RNA-protein complexes

  • Separate by magnetic bead binding method

  • Use Western blot analysis to detect specific protein interaction with RNA

• Computational prediction:

  • Tools like CatRAPID omics can be used to predict interactions between lncRNAs and proteins

  • Each RNA-protein pair receives an interaction score using matrix multiplication

These techniques have been successfully employed to demonstrate the interaction between RPS19BP1 and LINC00106 in prostate cancer cell lines .

What are the validated cell lines for studying RPS19BP1 expression and function?

Several cell lines have been validated for the study of RPS19BP1 expression and function:

These cell lines show detectable levels of endogenous RPS19BP1 and have been used successfully in various experimental applications including Western blot, immunoprecipitation, and functional studies .

How can the LINC00106/RPS19BP1/p53 axis be targeted in cancer research?

The LINC00106/RPS19BP1/p53 axis represents a promising target for cancer research, particularly in prostate cancer (PCa). Strategic approaches include:

• RNA Interference Strategies:

  • Transfection with siRNAs targeting LINC00106 or RPS19BP1 has been shown to significantly reduce cell proliferation and migration in PCa cell lines

  • Both si-LINC00106 and si-RPS19BP1 greatly promote p53 activity in cancer cells

• Dual-Luciferase Reporter Assays:

  • Can be employed to evaluate the regulatory activity of RPS19BP1 on the p53 signaling pathway

  • Co-transfect p53-Luc reporter plasmid with pcDNA3.1 expression plasmid and siRNA for 48 hours

  • Detect reporter gene activity using a dual-luciferase reporter assay apparatus

  • Standardize results following renal luciferase luminescence intensity

• Mechanistic Investigations:

  • Evidence suggests that LINC00106 and RPS19BP1 do not alter protein levels of p53 but rather modulate its activity

  • Western blot analysis has shown that expression of RPS19BP1 is not altered in cells with LINC00106 knockdown, indicating that protein stability is not affected

  • The axis likely functions by affecting p53 acetylation status through the SIRT1 deacetylase pathway

• Biomarker Development:

  • LINC00106 has been identified as substantially expressed in PCa patients and a significant prognostic factor

  • The LINC00106/RPS19BP1 axis has potential as a novel PCa biomarker

What are the optimal protocols for detecting post-translational modifications of RPS19BP1?

Detecting post-translational modifications (PTMs) of RPS19BP1 requires specialized techniques:

• Western Blot Analysis:

  • Use phospho-specific or acetylation-specific antibodies if available

  • Recommended dilutions: 1:500-1:2000

  • Include appropriate positive controls and modification-specific markers

  • Consider using Phos-tag™ gels for improved separation of phosphorylated proteins

• Mass Spectrometry:

  • Perform immunoprecipitation of RPS19BP1 using specific antibodies (dilution 1:50-1:200)

  • Digest precipitated proteins with trypsin

  • Analyze peptides by LC-MS/MS to identify PTMs

  • Search against protein databases with modifications as variable parameters

• Protein-Protein Interaction Analysis:

  • Co-immunoprecipitation can reveal interactions with modifying enzymes such as SIRT1

  • Follow published IP protocols (dilution 1:50-1:200)

  • Techniques like proximity ligation assay (PLA) can be used to visualize protein interactions in situ

• Functional Assays:

  • Site-directed mutagenesis of potential modification sites

  • p53 activity assays following mutation of specific residues

  • Dual-luciferase reporter assays to measure functional impact of modifications

Note that current commercial RPS19BP1 antibodies are primarily designed to detect unmodified forms of the protein , so specialized approaches may be necessary for comprehensive PTM analysis.

What are the technical challenges in optimizing RPS19BP1 antibody performance for various applications?

Researchers face several technical challenges when optimizing RPS19BP1 antibody performance:

• Molecular Weight Discrepancy:

  • While the theoretical molecular weight of RPS19BP1 is ~15 kDa, it is often observed at ~20 kDa in Western blots

  • This discrepancy may be due to post-translational modifications or different isoforms

  • Researchers should validate antibody specificity using positive controls and knockdown experiments

• Antibody Specificity:

  • Ensure specificity by using appropriate blocking agents and controls

  • Validation methods should include:

    • Testing in multiple cell lines with known RPS19BP1 expression

    • Confirming subcellular localization (nucleolar)

    • Using siRNA knockdown to confirm specificity of bands/signals

• Application-Specific Optimization:

  • Western Blot: Requires optimization of lysis conditions, protein loading, and transfer parameters

  • Immunofluorescence: May require different fixation methods (paraformaldehyde vs. methanol)

  • Immunoprecipitation: Buffer compositions significantly affect efficiency

• Cross-Reactivity Considerations:

  • While commercial antibodies claim species reactivity with human, mouse, and rat , cross-reactivity should be experimentally verified

  • Sequence homology analysis between species should be performed when working with non-human samples

• Immunogen Selection Impact:

  • Different commercial antibodies use different immunogens:

    • Some use recombinant fusion proteins of human RPS19BP1

    • Others use specific immunogen sequences (e.g., "CRDHLRVNLKFLTRTRSTVAESVSQQILRQNRGRKACDRPVAKTKKKKAEGTVFTEEDFQKFQQEYFGS")

  • The immunogen determines which epitopes are recognized, potentially affecting detection of particular protein domains or isoforms

What disease associations have been identified for RPS19BP1?

RPS19BP1 has been associated with several pathological conditions:

• Cancer:

  • Prostate Cancer: Significantly higher RPS19BP1 expression has been detected in PCa tissues compared to normal tissues

  • The LINC00106/RPS19BP1/p53 axis promotes proliferation and migration of PCa cells

• Neurological Disorders:

  • Amyotrophic Lateral Sclerosis 1 (ALS1): RPS19BP1 has been associated with this progressive neurodegenerative disease

  • Potential involvement in neurodegenerative mechanisms through p53 pathway modulation

• Other Conditions:

  • Inhibited Female Orgasm: Listed as a disease association, though the mechanistic connection remains unclear

• Chromosome 22-Related Disorders:

  • The RPS19BP1 gene maps to chromosome 22, which is associated with several genetic disorders

  • Mutations in genes on chromosome 22 are involved in Phelan-McDermid syndrome, Neurofibromatosis type 2, autism, and schizophrenia

  • Although direct involvement of RPS19BP1 in these disorders hasn't been established, its chromosomal location suggests potential associations

What are the validated protocols for investigating RPS19BP1's role in cellular stress responses?

RPS19BP1 is implicated in cellular stress response pathways, particularly through its interaction with SIRT1 and p53. Validated protocols include:

• Heat Stress Response Analysis:

  • RPS19BP1 is involved in cellular response to heat stress pathway

  • Subject cells to controlled heat shock (42-45°C for 30-60 minutes)

  • Monitor RPS19BP1 expression and localization changes using Western blot (1:500-1:2000 dilution) and immunofluorescence (1:50-1:200 dilution)

  • Assess co-localization with stress granule markers

• Cellular Senescence Pathway Investigation:

  • RPS19BP1 is implicated in the Cellular Senescence pathway

  • Induce senescence using appropriate stressors (e.g., H₂O₂, radiation, replicative exhaustion)

  • Detect senescence markers (β-galactosidase, p16, p21)

  • Analyze RPS19BP1 expression and its correlation with SIRT1 and p53 activation states

• p53 Activity Measurement:

  • Use dual-luciferase reporter assay with p53-Luc reporter plasmid

  • Co-transfect with pcDNA3.1 expression plasmid and siRNA targeting RPS19BP1

  • Measure after 48 hours using dual-luciferase reporter assay apparatus

  • Standardize results following renal luciferase luminescence intensity

• SIRT1-Mediated Deacetylation Assessment:

  • Immunoprecipitate p53 using specific antibodies

  • Probe for acetylated p53 using acetylation-specific antibodies

  • Manipulate RPS19BP1 levels through knockdown or overexpression

  • Monitor changes in p53 acetylation status in response to various stressors