SPIRE1 Antibody

What is SPIRE1 protein and what cellular functions does it serve?

SPIRE1 (Protein spire homolog 1) belongs to the family of Wiskott-Aldrich homology region-2 (WH2) proteins. It functions as an actin nucleation factor, specifically associated with the slow-growing pointed end of new actin filaments . SPIRE1 works in conjunction with FMN2 (Formin-2) to promote the assembly of nuclear actin filaments in response to DNA damage. This process facilitates the movement of chromatin and repair factors, enabling efficient DNA repair mechanisms . Understanding this protein's function provides context for experimental design when utilizing SPIRE1 antibodies in research applications focused on cytoskeletal dynamics and DNA damage response pathways.

What applications are SPIRE1 antibodies validated for in research settings?

SPIRE1 antibodies have been validated for multiple research applications with specific optimization parameters:

Each application requires specific optimization based on sample type and experimental conditions . Researchers should conduct preliminary titration experiments to determine optimal antibody concentrations for their specific experimental systems.

What are the technical specifications of commercially available SPIRE1 antibodies?

The commercially available SPIRE1 antibody (catalog #11295-1-AP) has the following specifications:

These specifications are essential for determining antibody compatibility with specific experimental designs and protocols .

How should I optimize antigen retrieval for SPIRE1 immunohistochemistry?

Effective antigen retrieval is critical for successful SPIRE1 detection in fixed tissues. The recommended protocol includes:

• Primary retrieval method: Use TE buffer at pH 9.0 with heat-induced epitope retrieval (pressure cooker or microwave heating)

• Alternative method: Citrate buffer at pH 6.0 may be used if primary method yields suboptimal results

• Incubation time: Optimize between 20-30 minutes at high temperature

• Cooling period: Allow 20 minutes gradual cooling to room temperature

• Washing: Perform 3x5 minute washes in PBS before proceeding to blocking step

These conditions have been validated specifically for human lung cancer tissue samples but should be optimized for other tissue types . Proper antigen retrieval significantly impacts staining intensity and specificity when working with SPIRE1 antibodies in fixed tissue specimens.

What controls should I include when using SPIRE1 antibodies in experimental procedures?

Rigorous experimental design requires appropriate controls when working with SPIRE1 antibodies:

Including these controls enables proper interpretation of results and troubleshooting of experimental issues. For studies involving SPIRE1's role in DNA damage response, additional controls showing induced DNA damage (e.g., γH2AX staining) should be considered to establish experimental context.

How can I optimize SPIRE1 antibody dilutions for different experimental applications?

Determining optimal antibody dilution requires systematic titration for each application:

• For IHC applications:

  • Begin with recommended range (1:50-1:500)

  • Prepare serial dilutions (e.g., 1:50, 1:100, 1:200, 1:500)

  • Apply to serial sections of positive control tissue

  • Evaluate signal-to-noise ratio and staining pattern at each dilution

  • Select dilution with strongest specific signal and minimal background

• For Western blot applications:

  • Test dilutions based on antibody sensitivity and protein abundance

  • Include appropriate loading controls

  • Quantify signal intensity using digital image analysis

  • Ensure signal remains in linear detection range

• For immunofluorescence applications:

  • Consider autofluorescence of tissue/cells when selecting dilutions

  • Test fixation methods that preserve epitope accessibility

  • Include counterstains for subcellular landmarks

Each experimental system requires optimization as antibody performance may vary with sample type and preparation method .

How can I use SPIRE1 antibodies to investigate DNA damage response mechanisms?

SPIRE1's involvement in nuclear actin filament assembly during DNA damage response can be investigated through:

• DNA damage induction protocols:

  • Treat cells with genotoxic agents (e.g., etoposide, hydroxyurea)

  • Apply UV or ionizing radiation at controlled doses

  • Verify damage induction via γH2AX staining

• Co-localization studies:

  • Perform dual immunofluorescence with SPIRE1 antibody and:

    • DNA damage markers (γH2AX, 53BP1)

    • Nuclear actin (with appropriate probes)

    • FMN2 (known SPIRE1 partner in damage response)

  • Analyze using confocal microscopy and quantitative co-localization metrics

• Temporal dynamics analysis:

  • Establish time-course experiments after damage induction

  • Fix cells at defined intervals (15min, 30min, 1h, 2h, 4h, etc.)

  • Quantify SPIRE1 nuclear localization, intensity, and pattern changes

  • Correlate with DNA repair progression markers

This approach can reveal how SPIRE1 contributes to the orchestration of nuclear actin assembly during DNA repair processes, as suggested by previous studies .

What approaches can I use to study post-translational modifications of SPIRE1?

Investigating post-translational modifications (PTMs) of SPIRE1 requires specialized techniques:

• Detection of phosphorylation:

  • Immunoprecipitate SPIRE1 using general antibodies

  • Probe with phospho-specific antibodies (anti-pSer, anti-pThr)

  • Alternatively, treat immunoprecipitates with phosphatase and observe mobility shifts

  • Employ Phos-tag gels for enhanced separation of phosphorylated species

• PTM induction experiments:

  • Expose cells to DNA damage (known to activate many kinase pathways)

  • Compare SPIRE1 PTM status before and after treatment

  • Use kinase inhibitors to identify responsible signaling pathways

• Mass spectrometry approaches:

  • Immunoprecipitate SPIRE1 from cells under different conditions

  • Process for MS analysis using PTM-oriented protocols

  • Analyze data using specialized database approaches for antibody research

The multiple observed molecular weights of SPIRE1 (50-60 kDa and 95 kDa) suggest potential post-translational modifications or alternative splicing events that could be functionally significant .

How can SPIRE1 antibodies be adapted for proteomics approaches?

Integrating SPIRE1 antibodies into proteomics workflows enables comprehensive analysis of protein interactions and modifications:

• Immunoprecipitation-mass spectrometry (IP-MS):

  • Use SPIRE1 antibodies for pull-down experiments

  • Process immunoprecipitates for MS analysis

  • Implement appropriate database searching strategies

  • Consider the limitations of current database sizes for comprehensive antibody identification

• Database considerations:

  • Ensure SPIRE1 sequence variants are represented in search databases

  • Balance database size with false discovery considerations

  • Consider that "larger database sizes increase analysis time" and can affect peptide detection rates

• Sample preparation optimization:

  • For SPIRE1 antibody detection, use whole plasma rather than depleted plasma samples

  • This approach yields higher detection rates compared to depleted samples

• Control samples:

  • Include negative controls (e.g., brain tissue samples have minimal antibody presence)

  • This helps distinguish genuine antibody peptides from false positives

By incorporating these methodological considerations, researchers can effectively study SPIRE1 and its interacting partners using advanced proteomics approaches.

Why might I observe different molecular weights for SPIRE1 in Western blot analysis?

The discrepancy between calculated (64 kDa) and observed molecular weights (50-60 kDa and 95 kDa) of SPIRE1 can be attributed to several factors:

• Post-translational modifications:

  • Phosphorylation may alter electrophoretic mobility

  • Other modifications (glycosylation, ubiquitination) could contribute to higher molecular weight bands

• Alternative splicing:

  • SPIRE1 may exist in multiple splice variants

  • Different variants would present distinct molecular weights

• Protein complexes:

  • Incomplete sample denaturation could result in detection of SPIRE1-containing complexes

  • These would appear as higher molecular weight bands (potentially around 95 kDa)

• Protein degradation:

  • Proteolytic cleavage during sample preparation may generate smaller fragments

  • Use of protease inhibitors and appropriate sample handling can minimize this issue

When interpreting Western blot results, researchers should be aware of these possible explanations for the observed molecular weight patterns .

How can I minimize background staining when using SPIRE1 antibodies in immunohistochemistry?

High background can compromise data interpretation in SPIRE1 immunohistochemistry. Implementing these methodological refinements can improve signal-to-noise ratio:

• Blocking optimization:

  • Extend blocking time (60 minutes minimum)

  • Test different blocking agents (BSA, normal serum, commercial blockers)

  • Ensure blocking agent is compatible with host species of secondary antibody

• Antibody dilution adjustment:

  • Further dilute primary antibody if background persists despite adequate blocking

  • Consider longer incubation with more dilute antibody (e.g., overnight at 4°C)

• Washing protocol enhancement:

  • Increase number and duration of washing steps

  • Use detergent (0.1% Tween-20) in wash buffers to reduce non-specific binding

  • Ensure complete buffer exchanges between steps

• Endogenous enzyme blocking:

  • For peroxidase-based detection, thoroughly block endogenous peroxidase activity

  • For alkaline phosphatase systems, include levamisole to block endogenous activity

• Tissue-specific considerations:

  • Apply optimized antigen retrieval for human lung cancer tissue (TE buffer pH 9.0)

  • Adjust protocols for tissues with high endogenous biotin (if using biotin-based detection)

Systematic optimization of these parameters will significantly improve SPIRE1 detection specificity in immunohistochemical applications.

How should I interpret SPIRE1 localization patterns in immunofluorescence experiments?

SPIRE1's subcellular localization provides functional insights, particularly in the context of DNA damage response:

• Normal conditions (without DNA damage):

  • Expect predominantly cytoplasmic localization

  • Potential association with cytoskeletal structures

  • Possible vesicular/endosomal pattern (diffuse or punctate)

• After DNA damage induction:

  • Look for increased nuclear localization

  • Potential co-localization with DNA damage foci

  • Association with nuclear actin structures

  • Co-localization with FMN2 (functional partner)

• Quantitative assessment:

  • Measure nuclear/cytoplasmic intensity ratios

  • Quantify co-localization with damage markers using Pearson's or Manders' coefficients

  • Track temporal changes following damage induction

• Cell-type specific variations:

  • Consider differentiation state and cell cycle phase

  • Tumor cells may show altered localization patterns compared to normal cells

Understanding these localization patterns is essential for interpreting SPIRE1's dynamic role in nuclear actin assembly during DNA damage response .

How can SPIRE1 antibodies be utilized in cancer research applications?

SPIRE1's potential roles in cancer biology can be investigated using antibody-based approaches:

• Expression profiling:

  • Analyze SPIRE1 expression across cancer types using tissue microarrays

  • Correlate expression with clinical parameters and outcomes

  • Validated in human lung cancer tissue samples

• Functional studies in cancer models:

  • Investigate SPIRE1's role in cancer cell migration (related to actin dynamics)

  • Explore its DNA damage response function in the context of therapy resistance

  • Study potential interactions with oncogenic signaling pathways

• Methodological considerations:

  • Optimize antigen retrieval specifically for cancer tissue types

  • Consider tumor heterogeneity when interpreting staining patterns

  • Use multiplexed approaches to correlate with established cancer markers

• Therapeutic implications:

  • Investigate whether SPIRE1 expression correlates with response to DNA-damaging therapies

  • Explore potential as a biomarker for treatment selection

These approaches leverage SPIRE1 antibodies to investigate potential roles in cancer biology, building on established connections to DNA damage response pathways .

How can mass spectrometry approaches be optimized for SPIRE1 antibody research?

Advanced mass spectrometry techniques offer powerful tools for antibody research when properly optimized:

• Database considerations:

  • Create appropriately sized databases containing SPIRE1 sequence variants

  • Balance database size to minimize false discovery rates while maintaining coverage

  • Understand that "larger database sizes (DB5-6) increase analysis time" and can affect peptide identification

• Sample type selection:

  • Use blood plasma rather than depleted plasma for antibody detection

  • Blood plasma samples yield significantly higher detection rates of both known (UniProt) and novel antibody peptides compared to depleted samples

  • Brain tissue can serve as negative control due to minimal antibody presence

• Peptide identification strategy:

  • Select peptides commonly present in antibodies for database creation

  • This approach "minimizes search time and the false discovery rate"

  • Balance between database coverage and practical search parameters

• Classification approaches:

  • Apply machine learning models (e.g., random forest) to distinguish sample types

  • Include both known antibody peptides and newly found antibody peptides as features

  • This combined approach improves classification performance for disease states

These methodological refinements enable more effective discovery and characterization of antibodies using mass spectrometry-based proteomics approaches.

What are the considerations for using SPIRE1 antibodies in super-resolution microscopy?

Super-resolution microscopy offers unprecedented insights into SPIRE1's subcellular organization:

• Sample preparation optimization:

  • Test different fixation protocols to preserve actin structures while maintaining epitope accessibility

  • Consider using smaller detection probes (Fab fragments, nanobodies) for improved resolution

  • Optimize buffer conditions to reduce background fluorescence

• Technique-specific considerations:

  • For STORM/PALM: Select appropriate photoswitchable fluorophores for SPIRE1 detection

  • For STED: Ensure fluorophore stability under depletion laser conditions

  • For SIM: Optimize signal-to-noise ratio through appropriate exposure settings

• Multi-channel imaging strategies:

  • Combine SPIRE1 labeling with actin probes to visualize nucleation events

  • Include DNA damage markers for functional studies

  • Design compatible fluorophore combinations with minimal spectral overlap

• Quantitative analysis approaches:

  • Implement cluster analysis to evaluate SPIRE1 distribution patterns

  • Apply molecule counting techniques to assess local concentration

  • Use drift correction and fiducial markers for precise co-localization studies

These methodological considerations enable nanoscale visualization of SPIRE1's role in actin nucleation and DNA damage response, providing insights inaccessible through conventional microscopy.