Phospho-NFKB2 (S865) Antibody

What is Phospho-NFKB2 (S865) Antibody and what does it detect?

Phospho-NFKB2 (S865) Antibody is a polyclonal antibody specifically designed to recognize NFKB2 (p100) when phosphorylated at serine residue 865. This antibody is typically developed by immunizing rabbits with a synthetic peptide derived from human NFκB-p100 surrounding the phosphorylation site of S865 . The antibody is critical for studying the non-canonical NF-κB pathway, where phosphorylation at S865 serves as a key regulatory step in the processing of p100 to the active p52 subunit. This site is located within the NF-κB-inducing kinase (NIK)-responsive domain of the p100 protein and is absolutely conserved in vertebrates from humans to fish .

What applications can Phospho-NFKB2 (S865) Antibody be used for?

Based on the product specifications, Phospho-NFKB2 (S865) Antibody can be employed in multiple research applications:

These applications enable researchers to investigate the phosphorylation status of NFKB2 at S865 in various experimental systems . The versatility of this antibody makes it valuable for both qualitative and quantitative analyses of non-canonical NF-κB pathway activation.

What species reactivity does the Phospho-NFKB2 (S865) Antibody demonstrate?

Most commercially available Phospho-NFKB2 (S865) antibodies demonstrate reactivity with:

• Human

• Mouse

• Rat

Some products may also have predicted reactivity with additional species based on sequence homology, though this requires validation before experimental use . When selecting an antibody for your research, it's essential to verify the species compatibility, especially when working with non-human model systems.

How should Phospho-NFKB2 (S865) Antibody be stored to maintain optimal activity?

For optimal preservation of antibody activity, storage recommendations include:

• Store at -20°C or -80°C upon receipt

• Avoid repeated freeze-thaw cycles which can compromise antibody integrity

• The antibody is typically provided in liquid form in PBS containing 50% glycerol, 0.5% BSA, and 0.02% sodium azide, which helps maintain stability during storage

Following these storage guidelines will help maintain the antibody's specificity and sensitivity over an extended period, ensuring reliable experimental results.

What controls should be included when using Phospho-NFKB2 (S865) Antibody?

Proper controls are essential for accurate interpretation of results with Phospho-NFKB2 (S865) Antibody:

Positive controls:

• Cells treated with known activators of the non-canonical NF-κB pathway

• Recombinant phosphorylated peptide (if available)

Negative controls:

• Unstimulated cells (baseline phosphorylation)

• Phosphatase-treated samples to verify phospho-specificity

• NFKB2 knockout samples or S865A mutant cells (if available)

• Peptide competition assays using the phosphorylated immunogenic peptide

Technical controls:

• Loading controls for Western blotting (β-actin, GAPDH)

• Nuclear/cytoplasmic fractionation markers when assessing subcellular localization

• Antibodies against total NFKB2 to normalize phosphorylation signals

The importance of controls is highlighted by studies showing variability in antibody specificity among different NF-κB antibodies, including batch-to-batch variations .

How can I differentiate between specific and non-specific binding when using this antibody?

To distinguish between specific and non-specific binding:

• Optimize blocking conditions: Use appropriate blocking agents (BSA, normal serum) to reduce non-specific interactions.

• Peptide competition: Pre-incubate the antibody with:

  • Phosphorylated S865 peptide (should block specific binding)

  • Non-phosphorylated S865 peptide (should not affect specific binding)

• Phosphatase treatment: Samples treated with lambda phosphatase should show reduced or absent signal compared to untreated samples.

• Titration experiments: Test multiple antibody dilutions to identify the optimal concentration that maximizes specific signal while minimizing background.

• Signal validation across techniques: Confirm findings using complementary methods (e.g., IF results should be validated by Western blotting).

Research has demonstrated that even widely used NF-κB antibodies can exhibit inappropriate cross-reactivity, emphasizing the importance of thorough validation .

What are the key considerations for using Phospho-NFKB2 (S865) Antibody in immunofluorescence studies?

When optimizing immunofluorescence protocols:

• Fixation method: Use 4% paraformaldehyde to preserve phospho-epitopes; avoid methanol fixation which can disrupt phosphorylation.

• Permeabilization: Gentle permeabilization with 0.1-0.3% Triton X-100 is typically effective.

• Antibody dilution: Start with manufacturer's recommended dilution (typically 1:200-1:1000) and adjust as needed.

• Blocking: Extensive blocking (1-2 hours) with 5% normal serum or BSA can reduce background.

• Signal validation: Compare patterns between stimulated and unstimulated cells to confirm specificity.

• Co-localization studies: Consider dual staining with total NFKB2 antibody to assess the proportion of phosphorylated protein.

• High-resolution imaging: Techniques like confocal microscopy can provide detailed information on subcellular localization .

What is the biological significance of NFKB2 phosphorylation at S865?

Phosphorylation of NFKB2 at S865 plays a crucial role in the non-canonical NF-κB signaling pathway:

• S865 is located in the NIK-responsive domain of the p100 protein, adjacent to other critical phosphorylation sites (S866 and S870) .

• These phosphorylation events create a recognition motif for the SCF-βTrCP ubiquitin ligase complex.

• This leads to polyubiquitination of p100 at K855, which targets the C-terminal portion for proteasomal processing.

• The processing generates the active p52 subunit, allowing formation of transcriptionally active dimers (predominantly p52/RelB) that regulate genes involved in:

  • Lymphoid organ development

  • B-cell maturation

  • Immune responses

  • Cell survival

The critical importance of this phosphorylation site is highlighted by the finding that a D865G mutation in NFKB2 results in autosomal-dominant B-cell deficiency with alopecia due to impaired processing of p100 to p52 .

How does phosphorylation at S865 relate to other post-translational modifications of NFKB2?

Phosphorylation at S865 functions within a coordinated network of post-translational modifications:

• Sequential phosphorylation: S865 phosphorylation occurs in proximity to S866 and S870, which are also phosphorylated by NIK and IKKα. These modifications likely occur in a coordinated manner and may be interdependent .

• Ubiquitination trigger: The phosphorylation events at S865, S866, and S870 collectively create a recognition motif for SCF-βTrCP ubiquitin ligase, leading to K855 polyubiquitination .

• Hierarchy of modifications: As noted in research on NF-κB, post-translational modifications often occur in a hierarchical manner, with phosphorylation serving as the initial event that enables subsequent modifications .

• Relationship to processing: These modifications collectively regulate the limited proteasomal processing of p100 to p52, a key step in non-canonical NF-κB pathway activation.

Understanding this network of modifications is essential for interpreting the significance of S865 phosphorylation in different experimental contexts.

What stimuli or treatments can induce phosphorylation of NFKB2 at S865 in cellular models?

While the search results don't explicitly list stimuli specific for NFKB2 S865 phosphorylation, activation of the non-canonical NF-κB pathway typically occurs through these ligands:

• Lymphotoxin β-receptor (LTβR) agonists

• B-cell activating factor (BAFF)

• CD40 ligand

• RANKL (Receptor activator of nuclear factor kappa-Β ligand)

• TWEAK (TNF-related weak inducer of apoptosis)

These ligands activate the pathway by stabilizing NIK, which then cooperates with IKKα to phosphorylate NFKB2/p100 at multiple sites including S865.

Experimental considerations:

• Include appropriate time course analysis (non-canonical pathway activation is typically slower than canonical pathway)

• Cell type-specific responses may vary

• Use positive controls such as known inducers of the non-canonical pathway

• Monitor multiple readouts of pathway activation to confirm specificity

How does the specificity of Phospho-NFKB2 (S865) Antibody compare to other phospho-specific antibodies targeting the NF-κB pathway?

When comparing phospho-specific antibodies, researchers should consider:

• Cross-reactivity concerns: Studies have demonstrated that many commercially available NF-κB antibodies show inappropriate cross-reactivity . A study examining p65 antibodies found variable specificity across different test models.

• Batch variation: Research has shown that antibody specificity can vary between batches of the same catalog number, resulting in contradictory findings between studies .

• Epitope recognition: Phospho-specific antibodies must distinguish between phosphorylated and non-phosphorylated forms of the protein, adding another layer of specificity requirements.

• Target distinction: When studying NF-κB signaling, it's important to recognize that different antibodies target distinct subunits and phosphorylation sites (e.g., phospho-p65 at S529/S536 vs. phospho-NFKB2 at S865), each with unique biological functions .

To properly evaluate specificity, researchers should perform:

• Western blots with appropriate positive and negative controls

• Phosphatase treatment controls

• Peptide competition assays

• Validation in knockout/knockdown systems when available

Can Phospho-NFKB2 (S865) Antibody be used to monitor treatment response in cellular models of inflammation or cancer?

Phospho-NFKB2 (S865) Antibody can effectively monitor treatment responses in disease models:

• Pathway-specific readout: Changes in S865 phosphorylation provide direct insight into drug effects on the non-canonical NF-κB pathway, which is implicated in various inflammatory conditions and cancers .

• Quantitative analysis approaches:

  • Western blotting with densitometry

  • ELISA-based quantification

  • Flow cytometry for single-cell analysis

  • HTRF (Homogeneous Time Resolved Fluorescence) for high-throughput screening

• Imaging-based approaches: High-resolution microscopy can reveal changes in the subcellular localization of phosphorylated NFKB2 following treatment .

• Experimental design considerations:

  • Establish baseline kinetics of S865 phosphorylation

  • Include time-course analyses (different compounds may affect the pathway with different kinetics)

  • Use multiple readouts of pathway activity (phosphorylation, processing, nuclear translocation, target gene expression)

  • Normalize phospho-signals to total NFKB2 levels

What are the implications of the D865G mutation on NFKB2 phosphorylation detection?

The D865G mutation in NFKB2 has significant implications for both biological function and antibody detection:

• Location and effect: The mutation is located immediately adjacent to the critical S866 phosphorylation site in the NIK-responsive domain .

• Clinical significance: This mutation has been identified in patients with autosomal-dominant B-cell deficiency with alopecia .

• Molecular impact: The D865G substitution likely disrupts the recognition sequence for NIK/IKKα kinases, affecting phosphorylation at nearby sites including S866 and potentially S865 itself .

• Detection challenges: For antibody-based detection:

  • The D865G mutation may alter the epitope recognized by the Phospho-NFKB2 (S865) antibody

  • This could result in false-negative results in patients carrying this mutation

  • Additional controls are necessary when studying samples with potential mutations in this region

• Functional consequence: The mutation results in impaired processing of p100 to p52, leading to an IκB-like action that inhibits NF-κB-dependent responses .

When working with clinical samples or studying NFKB2 mutations, researchers should consider these implications for accurate interpretation of phosphorylation status.

How can imaging flow cytometry be adapted for studying NFKB2 phosphorylation and localization?

Imaging flow cytometry combines the quantitative power of flow cytometry with the spatial resolution of microscopy and can be adapted for NFKB2 studies:

• Simultaneous assessment: This technique allows for concurrent analysis of phosphorylation status and subcellular localization, as demonstrated in studies of NF-κB p65 phosphorylation .

• Protocol considerations:

  • Fixation: Use 4% paraformaldehyde to preserve phospho-epitopes

  • Permeabilization: Optimize conditions to maintain cellular architecture while allowing antibody access

  • Antibody combinations: Co-stain with DAPI for nuclear identification, total NFKB2 antibody, and phospho-specific antibody

  • Controls: Include unstimulated cells, stimulated cells, and phosphatase-treated samples

• Analysis parameters:

  • Nuclear translocation can be quantified using similarity scores between DAPI and protein signals

  • Phosphorylation intensity can be measured in specific cellular compartments

  • Single-cell resolution allows identification of responding subpopulations

• Experimental applications:

  • Kinetic studies of phosphorylation and translocation

  • Inhibitor screening with quantitative readouts

  • Analysis of heterogeneous responses in mixed cell populations

This approach provides significant advantages over traditional biochemical methods by preserving spatial information while maintaining quantitative capabilities and statistical power .

Why might I observe inconsistent results with Phospho-NFKB2 (S865) Antibody across experiments?

Several factors can contribute to inconsistent results:

• Antibody batch variation: Research has demonstrated that different batches of the same antibody can show variable specificity . Consider validating each new lot received.

• Phosphorylation lability: Phosphorylation is highly dynamic and sensitive to experimental conditions. Ensure samples are:

  • Collected quickly

  • Processed in the presence of phosphatase inhibitors

  • Maintained at cold temperatures during processing

• Sample preparation variables:

  • Cell density effects on baseline signaling

  • Serum factors activating pathways

  • Stress responses during harvesting

• Technical factors:

  • Variations in transfer efficiency (Western blotting)

  • Incomplete permeabilization (IF/IHC)

  • Antibody degradation due to improper storage

• Biological variability:

  • Cell cycle-dependent phosphorylation

  • Confluency-dependent signaling

  • Microenvironmental influences

To minimize these issues:

• Standardize all protocols rigorously

• Process all comparative samples simultaneously

• Include appropriate controls in each experiment

• Consider pooling antibodies from different lots for critical experiments

How can I improve signal detection when using Phospho-NFKB2 (S865) Antibody in Western blotting?

To enhance signal detection in Western blotting:

• Sample preparation optimization:

  • Use potent phosphatase inhibitors in lysis buffers

  • Maintain cold temperatures throughout processing

  • Consider enrichment techniques (e.g., immunoprecipitation) for low-abundance phosphoproteins

• Technical considerations:

  • Use PVDF membranes (often superior for phospho-epitopes)

  • Optimize transfer conditions (lower methanol percentage may help)

  • Consider wet transfer for larger proteins like p100 (110 kDa)

• Blocking optimization:

  • Use 5% BSA rather than milk (milk contains phosphatases)

  • Consider commercial blocking buffers specifically designed for phospho-detection

• Antibody incubation:

  • Longer incubation times (overnight at 4°C)

  • Optimize antibody concentration through titration

  • Consider signal enhancers compatible with phospho-detection

• Detection system:

  • Use high-sensitivity ECL substrates

  • Consider fluorescent secondary antibodies for better quantification

  • Longer exposure times may be necessary for weak signals

If signal remains weak, consider alternative approaches such as the Phos-tag gel system, which can enhance separation of phosphorylated proteins.