rnf150 Antibody

What is RNF150 and why is it important in biological research?

RNF150 (Ring Finger Protein 150) is a protein containing a RING-type zinc finger motif known to be involved in protein-protein and protein-DNA interactions . It belongs to the Goliath family of proteins, which play roles in apoptosis and embryonic development . RNF150 is part of the RING finger family, which constitutes the largest E3 ubiquitin ligase family with 340 validated human members . While the specific function of RNF150 remains largely unknown, recent research has identified it as a novel MSI-related gene in gastric cancer, suggesting its potential as a prognostic biomarker .

The importance of RNF150 in research stems from its involvement in fundamental cellular processes through its presumed E3 ligase activity, as well as its emerging role in cancer biology. Studying RNF150 contributes to our understanding of ubiquitin-mediated protein degradation pathways and potential therapeutic targets in diseases like gastric cancer where RNF150 expression has shown prognostic significance .

What are the key characteristics of commercially available RNF150 antibodies?

Commercial RNF150 antibodies are available in multiple formats with distinct characteristics:

These antibodies are primarily intended for research applications and should not be used for diagnostic procedures, agricultural purposes, or as food additives . The differences in host, clonality, and epitope recognition make each antibody suitable for specific experimental requirements, with polyclonal antibodies offering broader epitope recognition and monoclonal antibodies providing greater specificity .

What is the molecular characterization of the RNF150 protein targeted by these antibodies?

RNF150 is characterized by the following molecular properties:

• Calculated molecular weight: 48 kDa (438 amino acids)

• Observed molecular weight: 43-44 kDa (in Western blot)

• Contains a RING-type zinc finger domain

• Cellular localization: Membrane; Single-pass type I membrane protein

• GenBank accession number: BC101992

• UniProt ID: Q9ULK6

• Gene ID (NCBI): 57484

• Synonyms: KIAA1214

RNF150's RING domain is crucial for its presumed E3 ubiquitin ligase activity, which likely enables the protein to participate in the ubiquitin-proteasome system for protein degradation. The discrepancy between calculated and observed molecular weights may be due to post-translational modifications or protein processing . Understanding these molecular characteristics is essential for validating antibody specificity and interpreting experimental results when using RNF150 antibodies.

How can researchers validate the specificity of RNF150 antibodies in their experimental systems?

Validating the specificity of RNF150 antibodies requires a multi-faceted approach:

• Positive and negative control tissues/cells: Compare antibody reactivity in samples with known RNF150 expression. Based on available data, mouse lung tissue, human heart tissue, mouse brain tissue, mouse eye tissue, and Y79 cells have shown positive Western blot signals for RNF150 . Compare these with tissues known to have low or no expression.

• Knockout/knockdown validation: Generate RNF150 knockout or knockdown models (using CRISPR-Cas9 or siRNA) and confirm loss of signal with the antibody. This represents the gold standard for antibody validation.

• Recombinant protein comparison: Test the antibody against purified recombinant RNF150 to confirm recognition of the target protein. For example, ab57453 has been tested against recombinant fragment used as immunogen with a predicted band size of 38 kDa .

• Molecular weight verification: Confirm that the detected protein appears at the expected molecular weight (43-44 kDa observed, 48 kDa calculated) . Any deviation should be investigated for potential isoforms or post-translational modifications.

• Peptide competition assay: Pre-incubate the antibody with excess immunizing peptide/protein and demonstrate loss of signal in the blocked sample compared to unblocked control.

• Cross-reactivity assessment: Test the antibody in multiple species if cross-reactivity is claimed. For instance, Proteintech's antibody (21438-1-AP) has been validated in human, mouse, and rat samples .

Researchers should document validation results thoroughly, as antibody performance can vary across different experimental conditions and biological systems.

What is the significance of RNF150 in gastric cancer research, and how are antibodies enabling these discoveries?

Recent research has identified RNF150 as a novel microsatellite instability (MSI)-related gene in gastric cancer (GC), positioning it as a promising prognostic biomarker . The significance of this finding lies in several key areas:

RNF150 antibodies have been instrumental in these discoveries by enabling protein-level validation of expression patterns observed at the mRNA level. Through techniques like immunohistochemistry, researchers have been able to confirm the differential expression of RNF150 in tissue samples, strengthening the connection between this protein and gastric cancer pathogenesis. Future research may explore RNF150 as a potential therapeutic target or biomarker for patient stratification in precision medicine approaches to gastric cancer treatment.

How might RNF150's presumed E3 ubiquitin ligase function relate to its emerging role in cancer biology?

RNF150's presumed E3 ubiquitin ligase function, conferred by its RING-type zinc finger domain, potentially connects to its emerging role in cancer biology through several mechanistic pathways:

• Protein homeostasis regulation: As an E3 ubiquitin ligase, RNF150 likely mediates the addition of ubiquitin to specific substrate proteins, targeting them for degradation via the proteasome . Dysregulation of this process could lead to abnormal accumulation or depletion of key proteins involved in cell cycle regulation, DNA repair, or apoptosis—all processes relevant to cancer development.

• Microsatellite instability connection: The observed association between RNF150 expression and microsatellite instability in gastric cancer suggests it may participate in DNA mismatch repair (MMR) regulation. E3 ligases can modulate MMR protein stability and function, potentially influencing the MSI phenotype.

• Apoptosis regulation: Given RNF150's membership in the Goliath family involved in apoptosis , it may regulate the ubiquitination and subsequent degradation of pro- or anti-apoptotic factors. Altered expression of RNF150 could shift the balance between cell survival and programmed cell death in cancer cells.

• Signaling pathway modulation: E3 ligases often regulate key signaling proteins through ubiquitination. RNF150 might target components of signaling pathways relevant to cancer, such as those controlling cell proliferation, differentiation, or migration.

• Potential therapeutic implications: Understanding RNF150's substrate specificity could identify novel therapeutic opportunities. The development of molecules that could modulate RNF150's E3 ligase activity, similar to approaches being explored for other E3 ligases, might represent a new avenue for targeted cancer therapy.

What are the optimal conditions for using RNF150 antibodies in Western blotting applications?

Achieving optimal results with RNF150 antibodies in Western blotting requires attention to several technical parameters:

Sample preparation and loading:

• Extract proteins using RIPA buffer supplemented with protease inhibitors

• Heat samples at 95°C for 5 minutes in reducing Laemmli buffer

• Load 20-40 μg of total protein per lane (adjust based on RNF150 abundance in your sample)

• Include positive control samples (e.g., mouse lung tissue, human heart tissue, Y79 cells)

Gel electrophoresis and transfer:

• Use 10-12% SDS-PAGE gels for optimal resolution of RNF150 (43-44 kDa)

• Transfer to PVDF membrane (preferred over nitrocellulose for this protein)

• Transfer at 100V for 60-90 minutes or 30V overnight at 4°C

Antibody incubation and detection:

• Block membrane with 5% non-fat dry milk in TBST for 1 hour at room temperature

• For rabbit polyclonal antibodies:

  • Dilute primary antibody 1:500-1:3000 in blocking buffer

  • Incubate overnight at 4°C with gentle rocking

• For mouse monoclonal antibodies:

  • Use at 1-5 μg/ml concentration

  • Incubate overnight at 4°C

• Wash 3-5 times with TBST (5 minutes each)

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

• Wash 3-5 times with TBST

• Develop using enhanced chemiluminescence (ECL) substrate

Expected results:

• RNF150 should appear as a band at 43-44 kDa

• Additional bands may represent isoforms, post-translational modifications, or degradation products

• Validate specificity using positive controls and blocking peptides if necessary

Troubleshooting notes:

• If signal is weak, increase antibody concentration or extend incubation time

• If background is high, increase washing steps or decrease antibody concentration

• For challenging samples, consider using gradient gels (4-15%) to improve separation

• Store membrane in TBST at 4°C if you need to strip and reprobe

These conditions should be optimized based on the specific antibody and sample characteristics in your experimental system.

What considerations are important when using RNF150 antibodies for immunohistochemistry (IHC)?

Successful immunohistochemistry with RNF150 antibodies requires careful attention to tissue processing, antigen retrieval, and staining protocols:

Tissue preparation:

• Fix tissues in 10% neutral buffered formalin for 24-48 hours

• Process and embed in paraffin following standard protocols

• Cut 4-5 μm sections onto adhesive slides (e.g., poly-L-lysine coated)

• Include appropriate positive control tissues (e.g., human colon tissue)

Antigen retrieval optimization:

• Heat-induced epitope retrieval (HIER) is recommended

• Primary option: TE buffer pH 9.0

• Alternative option: Citrate buffer pH 6.0

• Heat in pressure cooker or microwave until boiling, then maintain at sub-boiling temperature for 10-20 minutes

• Cool sections to room temperature (approximately 20 minutes)

Staining protocol:

• Block endogenous peroxidase with 3% H₂O₂ in methanol for 10 minutes

• Block non-specific binding with 5-10% normal serum from the species of the secondary antibody

• Dilute RNF150 antibody 1:50-1:500 in antibody diluent

• Incubate sections overnight at 4°C in a humidified chamber

• Wash 3 times with PBS or TBS (5 minutes each)

• Apply appropriate HRP-conjugated secondary antibody for 30-60 minutes at room temperature

• Wash 3 times with PBS or TBS

• Develop with DAB substrate for 5-10 minutes (monitor microscopically)

• Counterstain with hematoxylin, dehydrate, clear, and mount

Expected staining pattern:

• Based on RNF150's subcellular localization as a single-pass membrane protein , expect membranous staining pattern with potential cytoplasmic component

• Expression may vary based on tissue type and pathological state

• In gastric cancer studies, differential expression has been observed between MSI and MSS tumor samples

Critical quality controls:

• Include positive control tissue with known RNF150 expression

• Include negative controls (omission of primary antibody)

• Consider dual staining with markers of subcellular compartments to confirm localization

• Validate staining pattern with alternative RNF150 antibodies if possible

Quantification approaches:

• H-score method (intensity × percentage of positive cells)

• Digital image analysis for more objective quantification

• Compare expression between normal and pathological tissues as internal controls

These recommendations should be adapted based on the specific antibody characteristics and optimized for each laboratory's equipment and protocols.

How can researchers effectively use RNF150 antibodies in co-immunoprecipitation (Co-IP) experiments to identify protein interaction partners?

Co-immunoprecipitation with RNF150 antibodies offers valuable insights into protein-protein interactions but requires careful optimization:

Lysate preparation:

• Harvest cells at 80-90% confluence (approximately 1-2 × 10⁷ cells per condition)

• Use mild lysis buffers that preserve protein-protein interactions:

  • NP-40 buffer (1% NP-40, 150 mM NaCl, 50 mM Tris-HCl pH 8.0)

  • Add protease inhibitors, phosphatase inhibitors, and deubiquitinase inhibitors (e.g., N-ethylmaleimide) if studying ubiquitination

• Lyse cells on ice for 30 minutes with gentle agitation

• Clear lysate by centrifugation at 14,000 × g for 15 minutes at 4°C

Pre-clearing and antibody binding:

• Pre-clear lysate with protein A/G beads for 1 hour at 4°C

• Divide lysate into experimental and control samples:

  • Experimental: Add 2-5 μg of RNF150 antibody

  • Control: Add equal amount of non-immune IgG from the same species

• Incubate overnight at 4°C with gentle rotation

Immunoprecipitation and washing:

• Add pre-washed protein A/G beads (40-50 μl of slurry)

• Incubate for 2-4 hours at 4°C with gentle rotation

• Centrifuge at 1,000 × g for 1 minute at 4°C

• Wash beads 4-5 times with lysis buffer (without detergent in final wash)

• Elute bound proteins by boiling in SDS-PAGE sample buffer

Analysis of co-immunoprecipitated proteins:

• Separate proteins by SDS-PAGE

• Detect RNF150 and potential interaction partners by Western blotting

• For unbiased discovery of novel interactors: Submit samples for mass spectrometry analysis

Validation strategies for novel interactions:

• Reciprocal Co-IP (using antibody against the identified interactor)

• Proximity ligation assay (PLA) to confirm interaction in intact cells

• GST pull-down or yeast two-hybrid to confirm direct binding

• Functional validation through mutagenesis of interaction domains

Special considerations for RNF150:

• As a presumed E3 ubiquitin ligase, interactions may be transient

• Consider using proteasome inhibitors (e.g., MG132) to stabilize substrates

• For ubiquitinated substrates, perform denaturing IP to disrupt non-covalent interactions

• When studying membrane proteins, ensure adequate solubilization while preserving interactions

Controls to include:

• Input sample (5-10% of lysate used for IP)

• IgG control precipitation

• Negative control samples (cells with RNF150 knockdown/knockout)

• Positive control (known interacting protein if available)

By following these protocols and including appropriate controls, researchers can effectively use RNF150 antibodies to identify and validate protein interaction partners, providing insights into RNF150's biological functions and potential role in disease processes.

What are common challenges when using RNF150 antibodies and how can they be addressed?

Researchers working with RNF150 antibodies may encounter several challenges that can be systematically addressed:

Challenge 1: Weak or absent signal in Western blot

• Potential causes: Low RNF150 expression, insufficient antibody concentration, inadequate exposure time, ineffective antigen retrieval

• Solutions:

  • Increase antibody concentration (try 1:500 instead of 1:3000 for polyclonal antibodies)

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

  • Use more sensitive detection systems (e.g., SuperSignal West Femto)

  • Enrich your sample (e.g., immunoprecipitation before Western blot)

  • Verify RNF150 expression in your sample type using publicly available transcriptomic data

  • Ensure use of positive control samples (e.g., mouse lung tissue, human heart tissue)

Challenge 2: Multiple bands or unexpected molecular weight

• Potential causes: Protein degradation, post-translational modifications, isoforms, non-specific binding

• Solutions:

  • Use fresh samples and add protease inhibitors during extraction

  • Compare with recombinant RNF150 migration pattern

  • Perform peptide competition assay to identify specific bands

  • Check literature for reported post-translational modifications

  • Expected molecular weight is 43-44 kDa (observed) vs. 48 kDa (calculated)

Challenge 3: High background in immunohistochemistry

• Potential causes: Excessive antibody concentration, inadequate blocking, endogenous peroxidase activity, non-specific binding

• Solutions:

  • Optimize antibody dilution (start with 1:200 and titrate)

  • Extend blocking time (1-2 hours with 5-10% normal serum)

  • Ensure complete quenching of endogenous peroxidase

  • Try alternative antigen retrieval methods (TE buffer pH 9.0 or citrate buffer pH 6.0)

  • Include additional washing steps between incubations

Challenge 4: Poor reproducibility across experiments

• Potential causes: Antibody lot variation, inconsistent protocols, sample heterogeneity

• Solutions:

  • Standardize protocols and record detailed methods

  • Purchase larger antibody lots for long-term studies

  • Include internal controls in each experiment

  • Validate new antibody lots against previous results

  • Consider creating a positive control standard (e.g., cell lysate with known RNF150 expression)

Challenge 5: Cross-reactivity with other proteins

• Potential causes: Epitope similarity, high antibody concentration, non-specific binding

• Solutions:

  • Perform validation in RNF150 knockout/knockdown systems

  • Use multiple antibodies targeting different epitopes

  • Reduce antibody concentration to minimize non-specific binding

  • Pre-absorb antibody with non-specific proteins

  • Compare reactivity patterns across species if using in non-human samples

Challenge 6: Poor immunoprecipitation efficiency

• Potential causes: Insufficient antibody amount, inadequate incubation time, ineffective binding to beads

• Solutions:

  • Increase antibody amount (5-10 μg per IP)

  • Extend incubation time with antibody (overnight at 4°C)

  • Cross-link antibody to beads to prevent co-elution

  • Try alternative IP buffers to improve protein solubilization while maintaining interactions

Systematic troubleshooting and documentation of optimization steps will help establish reliable protocols for RNF150 detection across different experimental systems.

How can researchers optimize RNF150 antibody use for studying its potential role in the ubiquitin-proteasome system?

Investigating RNF150's presumed E3 ubiquitin ligase function requires specialized approaches to detect ubiquitination events and functional consequences:

Detecting RNF150-mediated ubiquitination:

• In vivo ubiquitination assays:

  • Transfect cells with tagged-ubiquitin (HA-Ub or His-Ub) and potential substrate

  • Treat with proteasome inhibitor (e.g., MG132, 10 μM for 4-6 hours)

  • Perform denaturing immunoprecipitation of substrate

  • Probe with anti-ubiquitin antibody to detect ubiquitination

  • Compare ubiquitination levels in RNF150 overexpression vs. knockdown conditions

• Proximity-dependent ubiquitination detection:

  • Use BioID or TurboID fused to RNF150 to identify proximal proteins

  • Verify proximal proteins as potential substrates through direct ubiquitination assays

  • Combine with mass spectrometry to identify ubiquitination sites (di-glycine remnant analysis)

• In vitro ubiquitination reconstitution:

  • Purify recombinant RNF150, E1, E2 enzymes, and potential substrates

  • Perform in vitro ubiquitination reaction with ATP and ubiquitin

  • Analyze by Western blot using RNF150 antibodies and substrate-specific antibodies

Optimizing immunoprecipitation for ubiquitination studies:

• Two-step IP protocol:

  • First IP: Immunoprecipitate RNF150 using RNF150 antibody

  • Second IP: Dissociate complexes with SDS and heat, dilute, then immunoprecipitate substrate

  • Western blot for ubiquitin or perform mass spectrometry

• Denaturing conditions to disrupt non-covalent interactions:

  • Lyse cells in buffer containing 1% SDS and 5 mM DTT

  • Heat at 95°C for 5 minutes

  • Dilute 10-fold with non-denaturing buffer

  • Proceed with IP using RNF150 antibody

Functional analysis of RNF150's E3 ligase activity:

• Substrate stability assays:

  • Treat cells with cycloheximide to inhibit protein synthesis

  • Monitor substrate protein levels over time (0-8 hours)

  • Compare stability in RNF150 wildtype vs. knockout/knockdown conditions

  • Use proteasome inhibitors as controls

• RING domain mutation analysis:

  • Generate RNF150 RING domain mutants (e.g., critical Cys/His residues to Ala)

  • Compare ubiquitination activity between wildtype and mutant RNF150

  • IP mutant and wildtype RNF150 to compare substrate binding vs. ubiquitination

Specialized detection methods:

By combining these approaches with careful use of RNF150 antibodies, researchers can effectively study RNF150's role in the ubiquitin-proteasome system and identify its potential substrates and biological functions in normal and pathological conditions.

What are the best practices for using RNF150 antibodies in multiplex immunofluorescence to study co-localization with potential interaction partners?

Multiplex immunofluorescence allows simultaneous detection of RNF150 and potential interaction partners to study their co-localization in situ. Here are best practices for this approach:

Sample preparation and fixation:

• Choose fixation based on target preservation:

  • 4% paraformaldehyde (PFA) for 10-15 minutes (general purpose)

  • Methanol (-20°C) for 10 minutes (membrane proteins, preserves some epitopes better)

  • Combined PFA/methanol for certain applications

• Optimize permeabilization (0.1-0.5% Triton X-100 or 0.1% saponin)

• Consider antigen retrieval methods used in IHC if working with FFPE tissues

Antibody panel design:

• Select RNF150 antibody with validated immunofluorescence performance

• Choose antibodies against potential interaction partners from different host species

• Include markers for relevant subcellular compartments (e.g., membrane markers)

• Validate each antibody individually before multiplex experiments

• Test for cross-reactivity between secondary antibodies

Sequential staining protocol:

• Block with 5-10% normal serum from secondary antibody species (1 hour, RT)

• Incubate with RNF150 antibody (1:50-1:200 dilution, overnight at 4°C)

• Wash 3× with PBS (5 minutes each)

• Apply fluorophore-conjugated secondary antibody (1:200-1:500, 1 hour, RT)

• Wash 3× with PBS

• If using same species antibodies: block with anti-species Fab fragments

• Repeat steps 2-5 for each additional primary/secondary antibody pair

• Counterstain nucleus with DAPI (1 μg/mL, 5 minutes)

• Mount with anti-fade mounting medium

Tyramide signal amplification (TSA) for same-species antibodies:

• Apply first primary antibody at lower concentration (1:1000-1:5000)

• Use HRP-conjugated secondary antibody

• Develop with tyramide-fluorophore (10 minutes)

• Microwave in citrate buffer to remove antibodies but preserve fluorophore

• Continue with next primary antibody

• This allows use of multiple antibodies from the same species

Controls for co-localization studies:

• Single antibody controls to assess bleed-through

• Secondary-only controls to assess non-specific binding

• Biological negative controls (tissues/cells not expressing target)

• Positive controls with known co-localization patterns

• Competition controls with blocking peptides

Image acquisition and analysis:

• Use confocal microscopy for precise co-localization analysis

• Maintain consistent acquisition settings across samples

• Acquire images at Nyquist sampling rate

• Perform point spread function correction if possible

• Quantify co-localization using:

  • Pearson's correlation coefficient

  • Manders' overlap coefficient

  • Object-based co-localization analysis

Advanced co-localization techniques:

• Förster resonance energy transfer (FRET) for direct protein-protein interactions (<10 nm)

• Proximity ligation assay (PLA) to detect interactions with high sensitivity

• Live-cell imaging with fluorescent protein fusions to track dynamic interactions

• Super-resolution microscopy (STORM, PALM, SIM) for nanoscale co-localization

Table: Recommended fluorophore combinations for multiplex RNF150 staining:

By following these best practices, researchers can effectively use RNF150 antibodies in multiplex immunofluorescence to study co-localization with potential interaction partners, providing spatial context to biochemical interaction data.