KEGG: spo:SPBC1105.07c
STRING: 4896.SPBC1105.07c.1
SPBC1105.07c is a protein-coding gene in Schizosaccharomyces pombe (fission yeast) that encodes a nuclear pore associated protein, specifically a predicted Thp1-Sac3 complex subunit . This protein is significant for research because it plays a role in nuclear pore complex function, which is essential for nucleocytoplasmic transport. Understanding the function and regulation of nuclear pore proteins provides insights into fundamental cellular processes such as gene expression regulation, mRNA export, and nuclear organization. The antibody against this protein enables researchers to study its localization, expression levels, and interactions with other proteins in various experimental conditions.
SPBC1105.07c antibody can be utilized in multiple experimental applications for studying the corresponding protein in S. pombe. Common applications include Western blotting for protein expression analysis, immunoprecipitation for protein-protein interaction studies, immunohistochemistry and immunofluorescence for localization studies, chromatin immunoprecipitation (ChIP) for DNA-protein interaction analysis, and flow cytometry for quantitative measurements in cell populations. When selecting experimental applications, researchers should first validate the antibody for their specific application, as antibody performance can vary substantially between different techniques . For optimal results, follow the validation procedures outlined in antibody literature, including assessment of specificity using knockout or knockdown controls.
Proper validation of SPBC1105.07c antibody is critical for generating reliable research data. Follow these methodological steps:
Test for specificity: Compare antibody performance in wild-type S. pombe strains versus strains with SPBC1105.07c deletion or knockdown. Any signal detected in knockout strains indicates non-specific binding .
Evaluate sensitivity: Determine the minimum detectable amount of target protein by testing the antibody against varying concentrations of purified SPBC1105.07c protein or cell lysates with known expression levels .
Assess reproducibility: Perform replicate experiments using the same antibody lot on different days and by different operators. Additionally, test antibodies from different lots to evaluate lot-to-lot consistency .
Include appropriate controls: Use positive controls (samples known to express SPBC1105.07c) and negative controls (samples without the target protein) in each experiment.
Optimize experimental conditions: Determine optimal antibody concentration, incubation times, and buffer compositions for your specific application.
This systematic validation approach ensures that experimental results will be reliable and reproducible, which is essential for publication-quality research.
Detecting low-abundance variants of SPBC1105.07c requires careful optimization of your experimental protocol. Implement these advanced strategies:
Signal amplification techniques: Consider using tyramide signal amplification (TSA) or similar approaches that can enhance detection sensitivity by 10-100 fold compared to standard detection methods.
Sample enrichment: Perform subcellular fractionation to isolate nuclear membrane components where SPBC1105.07c is predominantly localized, thereby increasing the relative concentration of your target protein.
Optimize protein extraction: For nuclear pore complex proteins, standard extraction buffers may be insufficient. Use specialized extraction buffers containing appropriate detergents (e.g., 0.5-1% NP-40 or Triton X-100) and salt concentrations (300-500 mM NaCl) to efficiently solubilize membrane-associated nuclear pore proteins.
Quantitative Western blotting: Implement fluorescence-based Western blotting with standards of known concentration to establish a calibration curve for precise quantification of low-abundance proteins .
Consider proximity ligation assay (PLA): This technique can detect protein-protein interactions with single-molecule sensitivity, useful for studying low-abundance interacting partners of SPBC1105.07c.
The optimal antibody dilution should be determined empirically through titration experiments, comparing signal-to-noise ratios across a range of concentrations. Remember that using excessive antibody can lead to nonspecific binding, while too little may result in false-negative results .
When facing conflicting results with SPBC1105.07c antibody across different experimental systems, implement this systematic troubleshooting approach:
Antibody evaluation: Verify antibody specificity using orthogonal methods. Compare results from different antibody clones targeting distinct epitopes of SPBC1105.07c. Differences in epitope accessibility may explain discrepancies between applications like Western blotting (denatured proteins) versus immunoprecipitation (native conformation) .
Experimental design analysis: Examine differences in experimental conditions (buffer compositions, fixation methods, incubation times) that might affect antibody performance. Document all experimental variables systematically.
Strain and genetic background considerations: S. pombe strains may have subtle genetic differences affecting SPBC1105.07c expression or localization. Sequence verify your strains to ensure they match reference genomes.
Post-translational modifications: SPBC1105.07c may undergo modifications (phosphorylation, ubiquitination, etc.) that affect antibody recognition. Use phosphatase treatment or other modification-specific approaches to determine if this contributes to conflicting results.
Cross-validation with tagged proteins: Generate strains expressing epitope-tagged SPBC1105.07c and compare results between antibody detection and tag detection to resolve discrepancies.
Multi-method verification: Implement at least three independent methods to study the protein (e.g., Western blot, mass spectrometry, and fluorescence microscopy) to build a consensus view of SPBC1105.07c biology.
For publication-quality research, always report all validation steps and data discrepancies transparently, following the guidelines for antibody validation outlined in current best practices .
Differentiating between old (maternal) and newly synthesized SPBC1105.07c protein requires specialized techniques that combine antibody detection with protein age discrimination:
Recombination-induced tag exchange (RITE): This technique allows tracking of old and new proteins through an inducible epitope tag switch. As demonstrated with other yeast proteins like Spc110, RITE can be adapted for SPBC1105.07c by integrating a cassette behind the gene that switches between different epitope tags (e.g., GFP to mRFP or Flag to V5) upon induction . The maternal protein retains the original tag while newly synthesized protein incorporates the new tag, allowing differential detection with tag-specific antibodies.
TimeSTAMP (Time-Specific Tag for Age Measurement of Proteins): This method uses a drug-dependent protease to cleave a tag from newly synthesized proteins. By combining this with SPBC1105.07c antibody detection, you can distinguish protein populations by age.
Pulse-chase experiments with amino acid labeling: Perform metabolic labeling with stable isotope-labeled amino acids (SILAC) followed by mass spectrometry to differentiate pre-existing from newly synthesized proteins. This can be combined with immunoprecipitation using SPBC1105.07c antibody for targeted analysis.
Photoconvertible fluorescent protein fusions: Create SPBC1105.07c fusions with proteins like Dendra2 that change emission spectra after photoactivation. After photoconversion, track old (converted) versus new (unconverted) protein pools using fluorescence microscopy.
This approach was successfully applied to study the distribution of maternal and newly synthesized Spc110 in yeast spindle pole bodies, revealing that at late anaphase, maternal Spc110 was predominantly located at the bud spindle pole body . Similar approaches could elucidate the dynamics of SPBC1105.07c incorporation into nuclear pore complexes during cell division.
Implementing comprehensive controls in SPBC1105.07c immunoprecipitation experiments is critical for generating reliable and interpretable data:
Input control: Always set aside a portion (typically 5-10%) of your starting material before immunoprecipitation to verify the presence and amount of target protein in your sample.
Negative controls:
Isotype control: Use an irrelevant antibody of the same isotype to identify non-specific binding to the antibody or beads.
No-antibody control: Process samples with beads alone to identify proteins that bind non-specifically to the bead matrix.
Knockout/knockdown control: Use lysates from strains with SPBC1105.07c deletion or depletion to confirm antibody specificity .
Positive controls:
Known interaction partners: Include detection of established SPBC1105.07c interacting proteins to verify successful immunoprecipitation.
Recombinant protein: Spike in purified SPBC1105.07c protein as a reference standard.
Reciprocal immunoprecipitation: If studying protein-protein interactions, confirm results by performing reverse immunoprecipitation using antibodies against the putative interaction partner.
Competitive peptide blocking: Pre-incubate the antibody with the immunizing peptide to demonstrate binding specificity.
Sequential immunoprecipitation: For complex protein assemblies, perform serial immunoprecipitations to distinguish direct from indirect interactions.
For quantitative analyses, incorporate isotope-labeled reference standards or implement label-free quantification approaches with appropriate statistical analysis. This comprehensive control strategy ensures that identified interactions are specific to SPBC1105.07c and not experimental artifacts.
Studying SPBC1105.07c phosphorylation requires a multifaceted experimental approach combining antibody-based detection with functional analysis:
Phosphorylation site identification:
Phospho-specific antibodies: If available, use antibodies that specifically recognize phosphorylated residues of SPBC1105.07c.
Mass spectrometry: Perform immunoprecipitation with SPBC1105.07c antibody followed by mass spectrometry to identify phosphorylation sites. This approach has successfully identified phosphosites in other yeast proteins like Spc110 .
Phosphatase treatment: Compare untreated samples with phosphatase-treated samples in Western blots to confirm the presence of phosphorylated forms.
Kinase identification:
Kinase inhibitor screening: Treat cells with specific kinase inhibitors and assess changes in SPBC1105.07c phosphorylation.
Kinase deletion/mutation: Analyze SPBC1105.07c phosphorylation in yeast strains with deletions or mutations in candidate kinases.
In vitro kinase assays: Test potential kinases directly using purified components.
Functional analysis:
Phosphomimetic and non-phosphorylatable mutants: Generate S. pombe strains expressing SPBC1105.07c with serine/threonine to alanine mutations (preventing phosphorylation) or to aspartate/glutamate mutations (mimicking phosphorylation).
Cell cycle synchronization: Analyze SPBC1105.07c phosphorylation across different cell cycle stages, as phosphorylation is often cell cycle-dependent, similar to what has been observed for Spc110 .
Phenotypic analysis: Examine cellular phenotypes (growth rates, nuclear morphology, mRNA export) in phosphorylation mutants.
Interaction dynamics:
Phosphorylation-dependent binding partners: Compare interactomes of wild-type versus phosphorylation mutant SPBC1105.07c using immunoprecipitation followed by mass spectrometry.
When interpreting results, consider that phosphorylation events may be hierarchical, with certain sites requiring prior phosphorylation of other sites, similar to what has been observed in other nuclear proteins in yeast .
To comprehensively analyze SPBC1105.07c localization throughout the cell cycle, implement these methodological approaches:
Cell synchronization strategies:
Nitrogen starvation and release: Synchronize S. pombe cells by nitrogen starvation followed by refeeding.
Hydroxyurea block: Arrest cells in early S phase.
cdc25 temperature-sensitive mutants: Achieve G2/M arrest at restrictive temperature.
Lactose gradient centrifugation: Physically separate cells based on size/cell cycle stage.
Immunofluorescence microscopy:
Co-localization with cell cycle markers: Use antibodies against known cell cycle stage-specific proteins alongside SPBC1105.07c antibody.
Nuclear pore complex co-staining: Include antibodies against stable nuclear pore components as reference points.
Optimized fixation protocols: Test multiple fixation methods (methanol, paraformaldehyde, combined approaches) as nuclear pore proteins can be sensitive to fixation conditions.
Super-resolution microscopy: Implement techniques like STORM or SIM to achieve nanometer-scale resolution of nuclear pore structures.
Live-cell imaging:
Fluorescent protein tagging: Create SPBC1105.07c-GFP fusions that preserve protein function.
Photobleaching experiments: Perform FRAP (Fluorescence Recovery After Photobleaching) to analyze protein dynamics at different cell cycle stages, similar to approaches used for Spc110 .
4D imaging: Capture Z-stacks over time to track dynamic changes in localization.
Biochemical fractionation:
Cell cycle-staged fractionation: Isolate nuclear envelope fractions from synchronized cells.
Quantitative Western blotting: Measure relative abundance in different cellular compartments.
Quantitative analysis:
Automated image analysis: Develop pipelines to quantify signal intensity and distribution patterns.
Statistical comparison: Apply appropriate statistical tests to compare localization patterns across cell cycle stages.
This comprehensive approach will yield spatiotemporal information about SPBC1105.07c dynamics that can be correlated with functional studies of nuclear pore complex assembly and disassembly during cell division.
When encountering western blot inconsistencies with SPBC1105.07c antibody, implement this systematic troubleshooting approach:
Sample preparation optimization:
Nuclear protein extraction: As SPBC1105.07c is a nuclear pore complex protein, ensure complete nuclear lysis using specialized buffers containing appropriate detergents and salt concentrations.
Protease inhibitors: Use fresh, complete protease inhibitor cocktails to prevent degradation.
Phosphatase inhibitors: Include phosphatase inhibitors if studying phosphorylated forms.
Denaturing conditions: Test different sample heating temperatures and times, as nuclear pore complex proteins can be sensitive to aggregation.
Technical optimization:
Gel percentage: Adjust acrylamide percentage to optimally resolve SPBC1105.07c (predicted molecular weight).
Transfer conditions: Test different transfer methods (wet, semi-dry), buffer compositions, and times.
Membrane selection: Compare PVDF and nitrocellulose membranes for optimal signal-to-noise ratio.
Blocking agents: Test different blocking solutions (milk, BSA, commercial blockers) as some may contain proteins that cross-react with the antibody.
Antibody optimization:
Signal development:
Detection method comparison: Compare ECL, fluorescent, and infrared detection systems.
Exposure time optimization: Capture multiple exposure times to ensure linearity of signal.
Quantitative assessment:
Use loading controls: Include multiple loading controls (e.g., histone H3 for nuclear fractions).
Implement internal standards: Include purified protein standards for quantitative comparisons.
If multiple bands are observed, determine if they represent degradation products, post-translational modifications, or splice variants by comparing to predicted molecular weights and using appropriate controls. Document all optimized conditions meticulously for reproducibility.
Managing cross-reactivity in immunofluorescence studies with SPBC1105.07c antibody requires careful optimization and validation strategies:
Antibody validation:
Genetic controls: Compare staining patterns in wild-type versus SPBC1105.07c knockout or knockdown strains to identify non-specific signals .
Absorption controls: Pre-incubate antibody with purified antigen to block specific binding sites, leaving only non-specific interactions visible.
Multiple antibodies: Use antibodies targeting different epitopes of SPBC1105.07c to confirm specificity of localization patterns.
Sample preparation optimization:
Fixation method comparison: Test multiple fixation protocols as they significantly impact epitope accessibility and preservation of nuclear architecture.
Permeabilization optimization: Adjust detergent type and concentration to ensure antibody access to nuclear pore complexes without disrupting structure.
Antigen retrieval: Implement epitope unmasking techniques if standard protocols yield weak signals.
Staining protocol adjustments:
Extended washing: Increase number and duration of washes to remove non-specific antibody.
Blocking optimization: Test different blocking agents (normal serum, BSA, casein) at various concentrations.
Sequential immunolabeling: For multi-color immunofluorescence, perform sequential rather than simultaneous antibody incubations.
Signal amplification with care: If using amplification methods, include additional controls to ensure specificity is maintained.
Advanced approaches:
Super-resolution microscopy: Techniques like STORM or STED provide higher resolution to distinguish specific from non-specific signals.
FRET analysis: For co-localization studies, implement Förster resonance energy transfer to confirm protein proximities at molecular scale.
Correlative light and electron microscopy: Combine immunofluorescence with electron microscopy for ultrastructural confirmation of localization.
Quantitative validation:
Line scan analysis: Perform intensity profile measurements across cellular structures.
Co-localization coefficients: Calculate Pearson's or Mander's coefficients with known nuclear pore markers.
Remember that the optimal antibody concentration for immunofluorescence may differ from that used in Western blotting. Signal-to-noise ratio should be the primary metric for determining optimal conditions .
Analyzing changes in SPBC1105.07c under stress conditions requires robust experimental design and careful data interpretation:
Experimental design considerations:
Stress condition standardization: Establish reproducible protocols for applying stressors (oxidative stress, heat shock, nutrient deprivation, DNA damage).
Time course analysis: Monitor changes at multiple time points after stress induction to capture dynamic responses.
Dose-response relationships: Test multiple intensities of stress to distinguish threshold effects from graded responses.
Recovery assessment: Include post-stress recovery periods to determine reversibility of changes.
Quantitative expression analysis:
Western blotting with internal standards: Include calibration curves with purified proteins for absolute quantification.
qRT-PCR: Correlate protein changes with mRNA levels to distinguish transcriptional from post-transcriptional regulation.
Protein half-life determination: Implement cycloheximide chase experiments to assess if stress affects protein stability.
Localization analysis:
Digital image analysis: Apply consistent thresholding and quantification parameters across all conditions.
Subcellular fractionation: Complement microscopy with biochemical fractionation to measure distribution changes.
Nuclear envelope integrity controls: Include markers of nuclear membrane integrity to distinguish true localization changes from nuclear disruption.
Functional correlation:
Phenotypic assays: Correlate SPBC1105.07c changes with functional outcomes (growth rates, nuclear transport efficiency).
Genetic interaction studies: Compare stress responses in wild-type versus strains with mutations in related pathway components.
Protein-protein interaction dynamics: Assess how stress affects SPBC1105.07c interactions using co-immunoprecipitation or proximity labeling.
Statistical analysis and visualization:
Appropriate statistical tests: Apply ANOVA with post-hoc tests for multi-condition comparisons.
Visualization tools: Present data with heat maps or radar plots to capture multi-dimensional changes.
Machine learning approaches: For complex datasets, implement clustering or dimension reduction techniques to identify patterns.
When interpreting results, consider that changes in nuclear pore complex proteins often reflect adaptive responses to maintain nuclear homeostasis under stress. Compare SPBC1105.07c responses to those of other nuclear pore components to determine if changes are specific or part of a coordinated nuclear pore complex response.
Proximity labeling offers powerful approaches for mapping SPBC1105.07c interaction networks within the native cellular environment:
BioID/TurboID adaptation for yeast:
Generate fusion constructs: Create SPBC1105.07c-BioID2 or SPBC1105.07c-TurboID fusions that maintain proper protein localization and function.
Optimize biotin supplementation: Determine optimal biotin concentration and incubation time for S. pombe.
Validation by microscopy: Confirm biotinylation pattern matches expected nuclear pore localization using fluorescent streptavidin.
Controlled expression: Use native promoter or regulatable systems to prevent artifacts from overexpression.
APEX2 proximity labeling:
Create SPBC1105.07c-APEX2 fusions: Design constructs with appropriate linkers to maintain enzyme activity.
Optimize labeling conditions: Determine minimal H₂O₂ exposure time that yields sufficient labeling without cellular damage.
Spatiotemporal control: Implement rapid labeling approaches to capture dynamic interactions at specific cell cycle stages.
Sample processing and analysis:
Stringent purification: Implement denaturing conditions during streptavidin purification to eliminate non-covalent interactions.
Sequential elution: Use biotin elution for standard BioID, or on-bead digestion for comprehensive identification.
Quantitative proteomics: Implement SILAC, TMT, or label-free quantification to compare interaction profiles across conditions.
Control subtraction: Use appropriate controls (BioID/TurboID alone, unrelated nuclear protein fusions) to identify specific interactions.
Verification and functional characterization:
Orthogonal validation: Confirm key interactions using co-immunoprecipitation or yeast two-hybrid assays.
Domain mapping: Create truncation mutants to determine interaction interfaces.
Functional genetics: Assess phenotypes of interaction partner deletions or mutations on nuclear pore complex assembly and function.
Network analysis:
Integration with existing datasets: Compare proximity labeling results with published nuclear pore complex interactomes.
Network visualization: Implement tools like Cytoscape for interaction network representation.
GO term enrichment: Identify biological processes enriched among interaction partners.
This approach will provide a comprehensive view of the SPBC1105.07c protein neighborhood within the nuclear pore complex, potentially revealing novel functional associations and regulatory mechanisms.
Investigating SPBC1105.07c's role in nuclear transport during specialized cellular processes requires tailored experimental approaches:
Meiosis-specific analysis:
Synchronous meiosis induction: Utilize established protocols (nitrogen starvation followed by refeeding) to synchronize S. pombe meiotic progression.
Stage-specific sampling: Collect samples at defined meiotic stages (pre-meiotic S phase, prophase I, metaphase I, anaphase I, metaphase II, anaphase II, spore formation).
Meiosis-specific mutants: Compare SPBC1105.07c dynamics in wild-type versus mutants defective in specific meiotic processes.
Nuclear transport cargo tracking: Monitor movement of meiosis-specific cargoes (e.g., transcription factors critical for sporulation) in relation to SPBC1105.07c function.
Specialized transport assays:
Fluorescent reporter systems: Implement nuclear import/export reporters with regulatable expression.
Single-molecule tracking: Use photoactivatable fluorescent protein fusions to track individual cargo molecules.
Selective permeabilization: Adapt semi-permeabilized cell assays for reconstituting transport in vitro.
Microinjection approaches: For larger cells or specific cargoes, develop microinjection techniques to introduce labeled substrates.
Structure-function analysis:
Domain deletion/mutation studies: Create targeted mutations in functional domains of SPBC1105.07c and assess effects on transport.
Inducible protein depletion: Implement auxin-inducible degron (AID) system for rapid SPBC1105.07c depletion during specific cellular processes.
Chimeric proteins: Swap domains between SPBC1105.07c and related proteins to identify critical functional regions.
Advanced imaging approaches:
FRAP/FLIP analysis: Measure nucleocytoplasmic transport kinetics in wild-type versus SPBC1105.07c mutant cells.
Single-plane illumination microscopy: Implement light sheet techniques for extended live imaging with minimal photodamage.
Correlative light-electron microscopy: Combine fluorescence and electron microscopy to examine nuclear pore ultrastructure.
Specific cellular conditions:
Nutrient stress response: Analyze transport dynamics during nitrogen or glucose starvation.
DNA damage response: Examine how genotoxic stress affects SPBC1105.07c function using radiomimetic drugs or UV irradiation.
Cell quiescence: Study transport in G0-arrested cells.
This multifaceted approach will reveal how SPBC1105.07c contributes to the adaptation of nuclear transport machinery during specialized cellular processes, potentially uncovering context-specific functions beyond its role in vegetative growth.
Integrating computational approaches with experimental data provides powerful insights into SPBC1105.07c structure-function relationships:
Structural prediction and analysis:
Homology modeling: Identify structural homologs of SPBC1105.07c in related organisms and generate models using tools like AlphaFold or SWISS-MODEL.
Domain architecture analysis: Define functional domains through sequence analysis tools (InterPro, Pfam) and validate experimentally.
Disorder prediction: Identify intrinsically disordered regions that may mediate dynamic interactions using predictors like PONDR or IUPred.
Molecular dynamics simulations: Explore conformational flexibility and potential interaction interfaces.
Experimental structure validation:
Targeted mutagenesis: Design mutations based on structural predictions and assess functional consequences.
Limited proteolysis: Map domain boundaries experimentally and compare with in silico predictions.
Hydrogen-deuterium exchange mass spectrometry: Identify structured versus flexible regions and validate computational models.
Cross-linking mass spectrometry: Determine spatial proximity of amino acid residues to constrain structural models.
Interaction surface prediction:
Interface prediction algorithms: Apply tools like SPPIDER or PredUs to identify potential protein-protein interaction surfaces.
Electrostatic analysis: Calculate surface charge distributions to predict interaction propensities.
Conservation mapping: Identify evolutionarily conserved surfaces that may mediate functionally important interactions.
Docking simulations: Model interactions with known partners and validate experimentally.
Functional annotation integration:
Phosphorylation site prediction: Use tools like NetPhos to predict potential phosphorylation sites and validate experimentally.
Post-translational modification mapping: Integrate mass spectrometry data on modifications with structural models.
Evolutionary analysis: Perform comparative genomics across fungal species to identify conserved functional motifs.
Network-based function prediction: Integrate protein interaction data with structural information to predict functional roles.
Integrated data visualization and analysis:
Structure-function correlation: Map experimental data (mutation effects, interaction sites, modifications) onto the structural model.
Integrative modeling platforms: Use tools like IMP (Integrative Modeling Platform) to combine diverse experimental constraints with computational models.
Machine learning approaches: Apply supervised learning to predict functional consequences of mutations based on structural features.
This integrated approach creates a feedback loop between computational prediction and experimental validation, progressively refining understanding of how SPBC1105.07c structure determines its function within the nuclear pore complex.