The protein SPAC14C4.10c is an uncharacterized protein from the fission yeast Schizosaccharomyces pombe . S. pombe serves as a model organism to study eukaryotic molecular and cellular biology . SPAC14C4.10c is encoded by an open reading frame (ORF) located on cosmid C14C4 of chromosome 1 in S. pombe .
SPAC14C4.10c is also known as Spr18 (SMC partner of rad18) . Spr18 is related to the structural maintenance of chromosomes (SMC) protein family . SMC proteins, such as Rad18, typically have ATP-binding domains at their N- and C-termini, with two coiled-coil domains separated by a hinge in the middle . Spr18 is a heterodimeric partner of Rad18, an essential gene involved in repairing DNA damage caused by ionizing radiation and in tolerating UV-induced DNA damage in S. pombe .
Rad18 is part of a high-molecular-weight complex that includes at least six other proteins . Spr18 is the largest of these proteins and is likely Rad18's heterodimeric partner . The N-terminal ATP-binding domain of Rad18 is essential for its functions, and a mutation near the C-terminus can separate its repair and essential functions .
The heterotrimeric G protein beta subunit Gnr1 is related to SPAC14C4.10c . It has a protein sequence that spans from 1 to 399 amino acids .
| Property | Value |
|---|---|
| NCBI Gene ID | 2539303 |
| UniProt ID | O59762 |
| Protein Size (# AA) | 399 |
| Predicted Species Reactivity | Schizosaccharomyces pombe |
| Product Format | Liquid |
| Application | WB, ELISA |
| Reconstitution and Storage | The shelf life is related to many factors, storage state, buffer ingredients, storage temperature and the stability of the protein itself. Generally, the shelf life of liquid form is 6 months at -20C/-80C. The shelf life of lyophilized form is 12 months at -20C/-80C. Repeated freezing and thawing is not recommended. Store working aliquots at 4C for up to one week. |
| Purity | Greater than 85% as determined by SDS-PAGE. |
| Storage Buffer | Tris-based buffer, 50% glycerol |
| Protein Range | 1-399 |
| Protein Name | heterotrimeric G protein beta subunit Gnr1 |
KEGG: spo:SPAC14C4.10c
STRING: 4896.SPAC14C4.10c.1
The Uncharacterized protein C14C4.10c is a protein encoded by the SPAC14C4.10c gene in Schizosaccharomyces pombe 972h- (fission yeast). It is classified as "uncharacterized" because its biological function has not been fully determined through experimental validation. The protein consists of 534 amino acids and is identified by the UniProt ID O13717 . While its precise role remains unknown, the protein sequence data is available in public databases, enabling researchers to make predictions about its potential functions using comparative genomics and bioinformatics approaches. Structural predictions suggest it may be a membrane protein, but definitive characterization requires experimental evidence from biochemical and genetic studies.
SPAC14C4.10c can be accessed across multiple databases using the following identifiers:
The genomic information for this protein indicates it contains two introns in its coding sequence, which is consistent with the eukaryotic gene structure typically found in S. pombe. Researchers should be aware that proper splicing verification is essential when working with recombinant expression, as the gene structure contains typical 5′- and 3′-splice consensus elements (GTAAGTA and TAG) . When designing experiments with this gene, these introns must be considered, especially when expressing the protein in prokaryotic systems that lack splicing machinery.
Multiple expression systems can be employed for the recombinant production of SPAC14C4.10c, each with distinct advantages and considerations:
| Expression System | Advantages | Considerations | Applications |
|---|---|---|---|
| E. coli | Rapid growth, high yield, low cost | Lacks eukaryotic post-translational modifications; potential improper folding | Initial functional studies, antibody production |
| Yeast (S. cerevisiae) | Similar to native environment, proper folding | Lower yield than E. coli; longer production time | Structural studies, functional assays |
| Insect cells | Advanced eukaryotic PTMs, proper folding | Higher cost, technical complexity | Interaction studies, structural analysis |
| Mammalian cells | Most sophisticated PTMs | Highest cost, lowest yield, most complex | Functional studies requiring mammalian modifications |
Several fusion tags can enhance the expression, solubility, and purification of recombinant SPAC14C4.10c:
| Fusion Tag | Size (kDa) | Function | Recommended Use Case |
|---|---|---|---|
| His-Tag | 0.8-2.0 | Metal affinity purification | Initial purification strategy; works under denaturing conditions |
| FLAG-Tag | 1.0 | Immunoaffinity purification | High-purity preparations, mild elution conditions |
| MBP | 42.5 | Solubility enhancement | Increasing solubility of difficult-to-express proteins |
| GST | 26 | Solubility and affinity purification | Functional studies with potential for pull-down assays |
| GFP | 27 | Fluorescent tracking | Localization studies, folding quality control |
| TrxA | 12 | Solubility enhancement | Proteins with numerous cysteines |
The choice of tag should be guided by the downstream applications and the protein's characteristics . For instance, if SPAC14C4.10c proves difficult to express in soluble form, MBP or TrxA tags may be beneficial. For localization studies, GFP fusion would be advantageous. Multiple constructs with different tags should be tested in parallel to determine optimal expression conditions. Researchers should also consider the potential impact of the tag on protein function and include appropriate controls with tag-cleaved protein in functional assays.
Purification of recombinant SPAC14C4.10c requires a strategic approach based on protein characteristics and fusion tags:
Initial assessment: Begin with small-scale expression trials to determine optimal conditions (temperature, induction time, inducer concentration).
Solubility screening: Test various lysis buffers with different detergents if the protein has predicted membrane domains.
Purification strategy development:
For His-tagged constructs: Use IMAC (Immobilized Metal Affinity Chromatography) with gradient elution
For GST-tagged constructs: Apply GSH-agarose affinity chromatography
For FLAG-tagged constructs: Utilize anti-FLAG immunoaffinity chromatography
Secondary purification: Implement size exclusion chromatography (SEC) or ion exchange chromatography for higher purity.
Quality control: Verify purity by SDS-PAGE and protein identity by Western blot or mass spectrometry .
For membrane proteins, special considerations include using mild detergents (DDM, CHAPS) throughout purification. Protein purity should be determined by SDS-PAGE, and quantity by Bradford/BCA/A280 assays . Researchers should optimize buffer conditions (pH, salt concentration, additives) to maintain protein stability and function throughout purification. Additionally, if the protein tends to aggregate, the addition of glycerol (5-10%) or specific stabilizing agents may improve yield and quality.
A systematic approach to characterizing SPAC14C4.10c function could include:
Bioinformatic analysis:
Sequence homology searches against characterized proteins
Domain and motif identification
Secondary structure prediction
Evolutionary conservation analysis
Genetic approaches:
Gene knockout/knockdown studies in S. pombe
Phenotypic analysis of mutant strains
Complementation studies
Synthetic lethality screens
Biochemical characterization:
Subcellular localization using GFP-fusion or immunostaining
Protein-protein interaction studies (Y2H, BioID, co-IP)
Post-translational modification analysis
Enzymatic activity assays based on bioinformatic predictions
High-throughput approaches:
RNA-seq to identify genes affected by SPAC14C4.10c deletion
Proteomics to identify interacting partners
Metabolomics to identify affected metabolic pathways
This multi-faceted approach, combining computational predictions with experimental validation, increases the likelihood of successfully determining the protein's function . Researchers should develop a hypothesis-driven experimental plan while remaining open to unexpected findings. Incorporating the scientific process framework, as outlined in student-scientist project models, can help maintain methodological rigor throughout the characterization process .
Several complementary techniques can help identify potential binding partners:
| Technique | Principle | Advantages | Limitations |
|---|---|---|---|
| Yeast Two-Hybrid (Y2H) | Protein interaction reconstitutes transcription factor | High-throughput, in vivo | High false positive rate, binary interactions only |
| Affinity Purification-MS | Co-purification of interacting proteins | Identifies protein complexes, quantitative | May miss transient interactions, requires good antibodies |
| BioID/TurboID | Proximity-based biotinylation | Captures transient interactions, works in native environment | Spatial resolution limited, may identify proximal non-interactors |
| FRET/BRET | Energy transfer between fluorophores | Real-time, in vivo dynamics | Technically challenging, requires protein engineering |
| Protein Arrays | In vitro binding to arrayed proteins | High-throughput, controlled conditions | Misses context-dependent interactions |
These approaches should be used in combination for cross-validation . For membrane proteins like SPAC14C4.10c (based on sequence analysis), specialized techniques such as split-ubiquitin Y2H or MYTH (membrane yeast two-hybrid) may be more appropriate. Researchers should validate identified interactions using reciprocal co-immunoprecipitation or functional assays. Computational predictions of protein-protein interactions based on co-expression, co-evolution, or structural modeling can help prioritize candidates for experimental validation.
CRISPR-Cas9 provides powerful approaches for studying SPAC14C4.10c function in S. pombe:
Complete gene knockout:
Design sgRNAs targeting the 5' region of the coding sequence
Include a selection marker for efficient screening
Create a clean deletion by removing the entire coding sequence
Domain-specific mutagenesis:
Introduce point mutations in predicted functional domains
Use homology-directed repair with donor templates containing desired mutations
Generate a panel of mutants affecting different protein regions
Endogenous tagging:
C- or N-terminal fusion with fluorescent proteins for localization studies
Addition of affinity tags for interaction studies
Introduction of inducible degrons for temporal control of protein levels
CRISPRi for conditional knockdown:
Use catalytically dead Cas9 (dCas9) fused to repressors
Enable titratable repression to study dosage effects
Create conditional phenotypes in essential genes
For S. pombe specifically, researchers should optimize transformation protocols and sgRNA design based on S. pombe codon usage and PAM preferences . Phenotypic analysis of CRISPR-edited strains should include growth rates under various conditions, cell morphology, cell cycle progression, and stress responses. Complementation with wild-type protein can confirm phenotype specificity, while rescue experiments with orthologs from other species can provide evolutionary insights.
Multi-omics data integration provides a comprehensive approach to inferring SPAC14C4.10c function:
Transcriptomics integration:
Analyze differential gene expression in knockout/knockdown cells
Identify co-expressed genes across conditions
Compare expression patterns with genes of known function
Proteomics integration:
Map protein-protein interaction networks
Identify post-translational modifications
Analyze protein abundance changes in different conditions
Metabolomics integration:
Detect metabolic changes in mutant strains
Identify accumulated or depleted metabolites
Map affected metabolic pathways
Integration strategies:
Pathway enrichment analysis across multiple -omics datasets
Network analysis to identify functional modules
Machine learning approaches to identify patterns across datasets
Researchers should implement data integration tools like Cytoscape, DAVID, or specialized multi-omics platforms to visualize and analyze relationships across datasets . When interpreting results, consideration should be given to both direct and indirect effects of SPAC14C4.10c perturbation. Time-course experiments can help distinguish primary from secondary effects. Validation of key findings using targeted approaches remains essential despite the comprehensive nature of -omics data.
Bioinformatic approaches offer valuable insights into potential functions of uncharacterized proteins:
Sequence-based analysis:
PSI-BLAST for detecting distant homologs
HMMER for identifying conserved domains
PROSITE for motif recognition
Disorder prediction (IUPred, PONDR)
Structure-based prediction:
Ab initio modeling (Rosetta, QUARK)
Homology modeling (SWISS-MODEL, Phyre2)
AlphaFold2 for accurate structure prediction
Active site prediction based on structural features
Evolutionary analysis:
Phylogenetic profiling to identify co-evolving genes
Evolutionary rate analysis to identify functional constraints
Synteny analysis to detect conserved genomic context
Functional inference methods:
Gene Ontology enrichment of similar proteins
Protein-protein interaction network analysis
Text mining of scientific literature
Integrated function prediction platforms (SIFTER, FunFams)
When applying these methods to SPAC14C4.10c, researchers should consider that the protein's uncharacterized status may indicate either unique functions or distant relationships to known proteins . Predictions should be treated as hypotheses to guide experimental design rather than definitive functional assignments. Confidence scores provided by prediction algorithms should be carefully evaluated, and consensus approaches using multiple tools often yield more reliable predictions.
When faced with contradictory data about SPAC14C4.10c function, researchers should:
Evaluate methodological differences:
Compare experimental conditions (media, temperature, strain backgrounds)
Assess technique limitations and specificity
Examine statistical power and reproducibility
Consider biological complexity:
Protein multifunctionality and context-dependent functions
Redundancy and compensatory mechanisms
Indirect effects versus direct functions
Reconciliation strategies:
Design experiments to directly test competing hypotheses
Implement orthogonal techniques to validate findings
Control for strain background effects through backcrossing
Perform epistasis analysis with related genes
Documentation and reporting:
Transparently report contradictory findings
Discuss possible explanations for discrepancies
Present evidence supporting and opposing each interpretation
When working with uncharacterized proteins like SPAC14C4.10c, contradictions often reflect incomplete understanding rather than experimental errors . Researchers should embrace this complexity while systematically narrowing down potential functions. Collaborative approaches involving labs with different expertise can help resolve contradictions through complementary experimental strategies. Finally, researchers should remain open to the possibility that SPAC14C4.10c may have multiple distinct functions depending on cellular context or environmental conditions.
Robust experimental design for SPAC14C4.10c studies requires appropriate controls:
| Control Type | Purpose | Implementation |
|---|---|---|
| Empty vector control | Controls for vector effects | Transform cells with expression vector lacking insert |
| Tag-only control | Controls for tag effects | Express tag alone without SPAC14C4.10c |
| Catalytic mutant | Validates enzymatic activity | If activity is predicted, mutate putative catalytic residues |
| Related protein control | Provides specificity context | Express characterized protein from same family |
| Wild-type rescue | Confirms phenotype specificity | Complement knockout with wild-type gene |
For interaction studies, researchers should include both positive controls (known interacting proteins) and negative controls (proteins unlikely to interact) . When performing localization studies, co-staining with established organelle markers provides essential reference points. For functional assays, dose-response relationships and time-course analyses strengthen causal inferences. Additionally, researchers should include technical replicates to assess method reliability and biological replicates to account for natural variation, adhering to the scientific process framework utilized in academic research training .
Cross-species comparison of SPAC14C4.10c orthologs presents several challenges:
Ortholog identification issues:
Low sequence conservation in rapidly evolving proteins
Presence of paralogs complicating one-to-one relationships
Gene duplication and loss events across lineages
Functional divergence considerations:
Neofunctionalization after duplication events
Adaptation to species-specific cellular environments
Changes in interaction partners across species
Technical challenges:
Different expression systems required for different species
Varying genetic manipulation tools across model organisms
Species-specific post-translational modifications
Analytical approaches:
Reciprocal BLAST for initial ortholog identification
Synteny analysis to confirm genomic context conservation
Complementation assays to test functional conservation
Researchers should use multiple sequence alignment tools specialized for distantly related sequences (e.g., MUSCLE, T-Coffee) and consider structure-based alignments when sequence similarity is low . Phylogenetic analysis should include appropriate outgroups and use models that account for varying evolutionary rates across protein regions. When testing functional conservation, expression of orthologs in the S. pombe background can directly assess complementation of SPAC14C4.10c deletion phenotypes, providing strong evidence for functional equivalence despite sequence divergence.
Investigating post-translational modifications (PTMs) of SPAC14C4.10c requires specialized approaches:
PTM prediction and targeting:
Computational prediction of likely modification sites
Conservation analysis of putative modification motifs
Literature review of modifications in related proteins
Experimental detection methods:
Mass spectrometry-based proteomics (MS/MS, PTM-specific enrichment)
Western blotting with PTM-specific antibodies
Radioactive labeling (e.g., 32P for phosphorylation)
Chemical labeling strategies (e.g., biotin switch for nitrosylation)
Functional significance assessment:
Site-directed mutagenesis of modified residues
Temporal analysis during cell cycle or stress responses
Inhibitor studies targeting specific modifying enzymes
In vitro enzymatic assays with modified and unmodified protein
PTM dynamics studies:
Quantitative proteomics across conditions
Pulse-chase experiments to determine modification turnover
Correlation with protein activity, localization, or interactions
For membrane proteins like SPAC14C4.10c may be, specialized extraction and enrichment protocols are required to maintain PTMs during preparation . When designing mutagenesis studies, researchers should consider both phosphomimetic (e.g., S to D/E) and non-phosphorylatable (e.g., S to A) mutations to assess functional impacts. Integration of PTM data with structural information can provide insights into how modifications might alter protein conformation, interaction surfaces, or enzymatic activity, contributing to a more complete understanding of SPAC14C4.10c regulation and function.
SPAC14C4.10c research provides an excellent framework for student training in molecular biology and biochemistry:
Project structure for undergraduate research:
Begin with bioinformatic analysis and hypothesis generation
Progress to recombinant protein expression and purification
Advance to functional characterization based on predictions
Culminate in integrative data analysis and presentation
Implementation of research training framework:
Assessment strategies:
Timeline structure:
This structure aligns with proven student-scientist curriculum models that integrate inquiry-based research experiences with professional development activities . Research on uncharacterized proteins like SPAC14C4.10c is particularly valuable for training as it emphasizes the discovery process, teaches students to deal with ambiguity, and models real scientific investigation rather than cookbook laboratory exercises.
Publications characterizing SPAC14C4.10c should include comprehensive data sets:
Sequence and structural information:
Complete sequence with accession numbers
Domain architecture diagrams
Structural models or experimental structures
Evolutionary conservation analysis
Expression and purification details:
Full construct designs including tags and linkers
Expression conditions optimization data
Purification strategy with yield and purity assessment
Stability and storage condition evaluations
Functional characterization:
Phenotypic analysis of deletion/knockdown strains
Localization data with appropriate controls
Interaction partner identification and validation
Biochemical activity assays with statistical analysis
Supporting data formats:
Representative images of key findings
Quantitative data in table format
Statistical analysis details
Raw data availability statement
Following the NIH guidelines for data tables in research publications ensures comprehensive reporting . Researchers should prepare tables that clearly present both positive and negative results, avoiding publication bias. For S. pombe-specific work, adherence to the community's gene and protein nomenclature standards is essential. Additionally, researchers should consider depositing raw data in appropriate repositories (e.g., ProteomeXchange for proteomics data, GEO for transcriptomics) to enhance reproducibility and enable meta-analyses.