Mono-Methyl-RELA (K314/K315) Antibody

What is the Mono-Methyl-RELA (K314/K315) Antibody and what epitope does it recognize?

The Mono-Methyl-RELA (K314/K315) antibody is a polyclonal antibody specifically raised against synthetic peptides derived from the p65 (RELA) protein around the mono-methylation sites of lysine residues 314 and 315. This antibody selectively recognizes the monomethylated form of these specific lysine residues within the RELA protein, a key subunit of the Nuclear Factor-κB (NF-κB) transcription factor complex . The antibody is designed to detect this specific post-translational modification without cross-reactivity to unmethylated RELA or other methylation states (di- or tri-methylation) at these residues.

How does the Mono-Methyl-RELA (K314/K315) modification differ from other RELA post-translational modifications?

RELA undergoes various post-translational modifications that regulate its activity and function. Mono-methylation at K314/K315 is distinct from other modifications such as:

• Acetylation at K314/K315, which is detected by different antibodies (e.g., Acetyl-RELA(K314/K315))

• Mono-methylation at K310, which is catalyzed by SETD6 and linked to tonic repression of NF-κB signaling

• Other modifications including phosphorylation and ubiquitination at various residues

Each modification has distinct functional consequences. For instance, while K310 methylation couples GLP activity at chromatin to repress NF-κB signaling , the K314/K315 methylation enhances the interaction with WSB1/2 E3 ligases, leading to ubiquitination and degradation of RELA .

What are the recommended experimental applications for this antibody?

According to the product data, the Mono-Methyl-RELA (K314/K315) antibody is validated for the following applications:

The antibody has been tested for reactivity with human, mouse, and rat samples, making it suitable for comparative studies across these species .

What are the optimal sample preparation methods when using Mono-Methyl-RELA (K314/K315) antibodies in chromatin immunoprecipitation (ChIP) experiments?

For optimal ChIP experiments with Mono-Methyl-RELA (K314/K315) antibodies:

• Crosslinking: Use 1% formaldehyde for 10 minutes at room temperature to preserve protein-DNA interactions involving methylated RELA

• Chromatin shearing: Optimize sonication to generate fragments of 200-500bp

• Antibody incubation: Use 2-5μg of antibody per IP reaction with overnight incubation at 4°C

• Critical controls: Include:

  • IgG negative control

  • Input sample (non-immunoprecipitated chromatin)

  • Positive control using antibody against total RELA

  • Peptide competition assay using synthetic mono-methylated and unmodified peptides to confirm specificity

This approach helps distinguish specific binding of methylated RELA to target genes from background signals and non-specific binding .

How should researchers validate the specificity of the Mono-Methyl-RELA (K314/K315) antibody in their experimental system?

Proper validation requires multiple complementary approaches:

• Peptide competition assays: Pre-incubate the antibody with increasing concentrations of the mono-methylated K314/K315 peptide antigen prior to use in Western blot or immunoprecipitation. A specific antibody will show diminished signal when blocked with the specific peptide.

• Recombinant protein controls: Test against:

  • In vitro methylated wild-type RELA (using appropriate methyltransferases)

  • Unmethylated RELA

  • RELA with K314R/K315R mutations (non-methylatable)

• Cellular validation:

  • Overexpress the methyltransferase responsible for K314/K315 methylation and confirm increased signal

  • Use siRNA knockdown of the relevant methyltransferase to decrease signal

  • Employ CRISPR/Cas9 to generate K314R/K315R mutant cell lines as negative controls

• Mass spectrometry verification: Confirm the methylation status of immunoprecipitated RELA to provide definitive evidence of antibody specificity .

What is the recommended protocol for preparing nuclear extracts to maximize detection of Mono-Methyl-RELA (K314/K315)?

To maximize detection of nuclear mono-methylated RELA:

• Rapid nuclear isolation: Use ice-cold buffers with gentle lysis to preserve methylation status

  • Hypotonic buffer A (10mM HEPES pH 7.9, 10mM KCl, 1.5mM MgCl₂, 0.34M sucrose, 10% glycerol)

  • Add 0.1% Triton X-100 for plasma membrane disruption

  • Centrifuge at 1,300×g for 4 min at 4°C to collect nuclei

• Nuclear extraction buffer: 20mM HEPES pH 7.9, 420mM NaCl, 1.5mM MgCl₂, 0.2mM EDTA, 25% glycerol

• Critical protease inhibitors: Complete protease inhibitor cocktail

• Phosphatase inhibitors: 1mM Na₃VO₄, 1mM NaF

• Deacetylase inhibitors: 10mM sodium butyrate, 5μM trichostatin A

• Methylation preservation: Add 5mM nicotinamide and 50μM DZNep to inhibit demethylases

• Reducing agents: Include 1mM DTT to preserve protein structure

This protocol minimizes degradation of methylated proteins and prevents artificial loss of the K314/K315 methylation mark during sample preparation .

How does mono-methylation of RELA at K314/K315 interact with WDR domain-containing proteins and what methodologies best characterize these interactions?

Mono-methylation of RELA at K314/K315 creates a binding platform for WD40 repeat (WDR) domain-containing proteins, particularly WSB1 and WSB2, which function as substrate recognition components of E3 ubiquitin ligase complexes . To characterize these interactions:

• Computational modeling: Studies have revealed that the WDR domains of WSB1/2 contain a seven-bladed β-propeller structure that specifically recognizes mono-methylated lysine residues. Key residues like D158 in WSB2 (equivalent to D175 in WSB1) coordinate with the mono-methylated lysine .

• Experimental approaches:

  • GST pulldown assays: Using recombinant WDR domains and in vitro methylated RELA peptides

  • Co-immunoprecipitation: With wild-type versus K314R/K315R RELA mutants

  • Proximity ligation assays: To visualize interactions in situ

  • Water-mediated hydrogen bond network analysis: Investigation of E28 in WSB2 forming a water-bridged interaction with mono-methylated K314/K315, similar to interactions seen between H3K4me2 and E322 in WDR5 .

Experimental data show that mutations of E28A and D158A in WSB2 reduce binding to methylated RELA, with D158A causing a stronger reduction, confirming the computational model predictions .

What are the current hypotheses regarding the enzymes responsible for mono-methylation of RELA at K314/K315 and how can researchers investigate these methyltransferases?

Current hypotheses suggest several potential lysine methyltransferases (KMTs) may catalyze mono-methylation of RELA at K314/K315:

To systematically identify these enzymes:

• In vitro methyltransferase screening: Incubate recombinant RELA with various purified KMTs and S-adenosylmethionine (SAM), followed by mass spectrometry or antibody detection

• CRISPR/Cas9 KMT library screens: Create a focused library targeting all known and predicted KMTs, screen for loss of K314/K315 methylation

• Proteomic approach: Use biotinylated RELA peptides (unmethylated) as bait to capture potential methyltransferases from nuclear extracts

• Domain-focused analysis: Compare to known similar methylation events, such as RelA K310 methylation by SETD6 , to identify enzymes with similar substrate recognition patterns

How can researchers distinguish between the functional effects of mono-methylation versus acetylation at RELA K314/K315 when these modifications may occur at the same residues?

Distinguishing between these competing modifications requires sophisticated methodology:

• Sequential ChIP (Re-ChIP): First immunoprecipitate with anti-RELA antibody, then perform a second IP with either anti-acetyl or anti-methyl antibodies to identify distinct genomic binding sites for each modified form.

• Mass spectrometry quantification: Use parallel reaction monitoring (PRM) or multiple reaction monitoring (MRM) mass spectrometry to quantify relative abundance of each modification under different stimulation conditions.

• Temporal dynamics analysis: Perform time-course experiments following NF-κB stimulation to determine if these modifications occur sequentially or competitively.

• Site-specific mutants and mimetics: Generate K314Q/K315Q mutants (acetylation mimetics) and compare their function to wild-type or methylation-competent forms.

• Enzyme modulation:

  • Inhibit histone deacetylases (HDACs) to promote acetylation

  • Inhibit methyltransferases to block methylation

  • Analyze the resulting shift in modification balance and functional outcomes

• Modification-specific interactome analysis: Identify proteins that specifically interact with acetylated versus methylated RELA using modified peptide pulldowns combined with mass spectrometry .

What are the most common causes of false negative results when using Mono-Methyl-RELA (K314/K315) antibodies and how can they be addressed?

False negative results may stem from several sources:

• Loss of methylation during sample preparation:

  • Solution: Include methyltransferase inhibitors (e.g., 5mM nicotinamide) and demethylase inhibitors in all buffers

  • Use rapid extraction protocols at 4°C to preserve labile modifications

• Low nuclear abundance of methylated form:

  • Solution: Enrich for nuclear fractions before Western blotting

  • Consider stimulating cells with appropriate agonists that induce RELA translocation and methylation

• Competition with other modifications:

  • Solution: Pre-treat samples with phosphatases if phosphorylation interferes with antibody binding

  • Use cell models with HDAC inhibitors to reduce competing acetylation

• Antibody storage and handling issues:

  • Solution: Avoid repeated freeze-thaw cycles

  • Store antibody in small aliquots at -80°C

• Epitope masking by protein-protein interactions:

  • Solution: Include 0.1% SDS or other mild denaturants in IP buffer

  • Consider sonication or other gentle disruption methods

• Degradation of methylated RELA by ubiquitin-proteasome system:

  • Solution: Treat cells with proteasome inhibitors (e.g., MG132) before sample collection .

How can researchers ensure reproducibility when quantifying changes in RELA K314/K315 mono-methylation levels across experimental conditions?

To ensure reproducible quantification:

• Standardized sample preparation:

  • Use consistent cell numbers and lysis conditions

  • Process all samples in parallel

  • Include methylation stabilizing agents (e.g., methyltransferase/demethylase inhibitors)

• Loading controls:

  • Normalize to total RELA levels using validated anti-RELA antibodies

  • Include technical replicates with varying loading amounts to ensure linearity of signal

• Quantification method standardization:

  • Use digital imaging systems with linear dynamic range

  • Avoid saturated signals which prevent accurate quantification

  • Apply consistent background subtraction methods

• Reference standards:

  • Include in vitro methylated recombinant RELA as a positive control

  • Create standard curves with known quantities of methylated peptides

• Statistical rigor:

  • Perform at least three biological replicates

  • Apply appropriate statistical tests (paired t-tests, ANOVA)

  • Report both fold-changes and absolute values when possible

• Validation with orthogonal methods:

  • Complement Western blot data with ELISA or mass spectrometry

  • Consider using a second antibody against the same modification from different vendors .

What potential cross-reactivity issues might affect data interpretation when using Mono-Methyl-RELA (K314/K315) antibodies, and how can these be controlled for?

Potential cross-reactivity concerns include:

• Recognition of similar methylated motifs in other proteins:

  • Control: Perform immunoprecipitation followed by mass spectrometry to identify all bound proteins

  • Validate with RELA knockout cells to confirm specificity

• Different methylation states (di/tri-methylation):

  • Control: Test antibody against synthetic peptides with different methylation states

  • Include competitive binding assays with differently methylated peptides

• Recognition of acetylated K314/K315:

  • Control: Compare signal patterns with acetyl-specific antibodies

  • Use HDAC inhibitors to increase acetylation and determine if this affects methylation signal

• Methylation at adjacent or similar RELA sites (e.g., K310):

  • Control: Test against RELA with K310R mutation but wild-type K314/K315

  • Compare with antibodies specific for other methylation sites

• Species cross-reactivity variations:

  • Control: Validate in multiple species if performing comparative studies

  • Align sequences across species to identify potential epitope differences

Definitive controls include:

• Peptide competition assays with both target and non-target peptides

• CRISPR/Cas9-generated K314R/K315R RELA mutant cell lines as negative controls

• Testing in multiple cell lines with varied RELA expression levels .

How does mono-methylation of RELA at K314/K315 contribute to NF-κB signaling dynamics in different cellular contexts?

Mono-methylation of RELA at K314/K315 regulates NF-κB signaling through several mechanisms:

• Protein stability regulation: The mono-methylation serves as a recognition signal for WSB1/2 E3 ubiquitin ligases, targeting chromatin-bound methylated RELA for ubiquitination and subsequent degradation. This creates a feedback mechanism to limit sustained NF-κB activation .

• Context-dependent transcriptional effects:

  • In inflammatory conditions: Methylation may serve as a checkpoint to prevent hyperactivation

  • In cancer: Aberrant methylation patterns may contribute to constitutive NF-κB activation

  • In immune cells: Methylation modulates the duration and intensity of NF-κB-driven gene expression

• Integration with other signaling pathways:

  • Crosstalk with WD40-domain containing proteins suggests integration with other cellular processes

  • Computational modeling has revealed structural similarities to interactions between methylated histones and reader domains, suggesting evolutionary conservation of methylation-based signaling mechanisms .

Future investigations should employ cell-type specific methyltransferase manipulation combined with chromatin immunoprecipitation sequencing (ChIP-seq) using the Mono-Methyl-RELA (K314/K315) antibody to map genome-wide binding patterns under different stimulation conditions.

What methodological advances are needed to better understand the interplay between different RELA post-translational modifications, including K314/K315 mono-methylation?

Several methodological advances would significantly enhance our understanding:

• Single-cell modification mapping: Developing techniques to measure multiple PTMs on RELA simultaneously at single-cell resolution would reveal cell-to-cell heterogeneity and modification crosstalk.

• Live-cell methylation sensors: Engineered FRET-based sensors to monitor RELA methylation dynamics in real-time could reveal temporal and spatial regulation.

• Advanced mass spectrometry approaches:

  • Top-down proteomics to maintain intact protein analysis rather than peptide fragments

  • Improved sensitivity to detect low-abundance modified forms

  • Quantitative multiplexed approaches to monitor multiple modifications simultaneously

• CRISPR-based modification-specific reporters: Engineer cells with modification-specific luminescent or fluorescent reporters to monitor methylation dynamics.

• Structural biology advancements:

  • Cryo-EM structures of methylated RELA bound to different interaction partners

  • Hydrogen-deuterium exchange mass spectrometry to map conformational changes induced by methylation

• Computational frameworks: Develop predictive models of modification crosstalk based on kinetic parameters of the enzymes responsible for adding and removing different modifications .

How might advances in understanding RELA K314/K315 mono-methylation inform therapeutic approaches targeting NF-κB in inflammatory diseases and cancer?

Advances in understanding RELA K314/K315 mono-methylation offer several therapeutic possibilities:

• Targeted degradation approaches:

  • Compounds that enhance WSB1/2 recognition of methylated RELA could increase targeted degradation

  • PROTAC (PROteolysis TArgeting Chimera) technology could be adapted to recognize methylated RELA specifically

• Methyltransferase inhibitors/activators:

  • Once the responsible methyltransferase is identified, small molecule inhibitors could be developed

  • Tissue-specific delivery systems could target methylation machinery in specific disease contexts

• Reader domain antagonists:

  • Small molecules disrupting the interaction between methylated K314/K315 and its reader proteins

  • Peptidomimetics that compete for binding to methylated RELA

• Combination therapy strategies:

  • Synergistic approaches targeting both methylation and other modifications (e.g., acetylation inhibitors)

  • Sequential modulation of different modifications to reset aberrant signaling

• Biomarker development:

  • The Mono-Methyl-RELA (K314/K315) antibody could be used to develop diagnostic assays

  • Methylation levels could predict responsiveness to NF-κB-targeting therapies

Specific examples based on current research include potential adaptation of technologies similar to those used for the anti-BCMA antibody-drug conjugate GSK2857916, which has shown promising results in multiple myeloma by targeting specific cell surface proteins . Similar approaches could be developed targeting pathways downstream of aberrant RELA methylation.