Recombinant Schizosaccharomyces pombe Protein lunapark homolog (SPCC1620.07c)

What is the SPCC1620.07c gene and its protein product?

SPCC1620.07c is a protein-coding gene from Schizosaccharomyces pombe (fission yeast) that encodes the protein lunapark homolog. The gene has been assigned Entrez Gene ID 2538940 and produces the mRNA transcript NM_001023456.2, which translates to the protein product NP_588465.1 . The full-length protein consists of 334 amino acids with a specific sequence that includes multiple functional domains. As a model organism, S. pombe provides valuable insights due to its cellular properties that share features with human cells, making this protein potentially relevant for comparative studies with mammalian homologs .

What are the optimal storage conditions for recombinant SPCC1620.07c protein?

Recombinant SPCC1620.07c protein is typically supplied in a Tris-based buffer with 50% glycerol, specifically optimized for this protein's stability . For short-term use, working aliquots can be stored at 4°C for up to one week. For extended storage, the protein should be kept at -20°C, while long-term preservation is best achieved at -80°C . Importantly, repeated freeze-thaw cycles should be avoided as they can compromise protein integrity and function. When preparing experiments, it is advisable to create single-use aliquots to prevent degradation from multiple freeze-thaw events.

What expression systems are typically used for producing recombinant SPCC1620.07c?

While the search results don't specify the expression system used for the commercially available SPCC1620.07c protein, recombinant proteins from S. pombe are commonly expressed in either bacterial systems (E. coli), yeast systems (including S. pombe itself or S. cerevisiae), or insect cell systems. Each expression system offers distinct advantages depending on the research application. For functional studies requiring post-translational modifications similar to the native protein, expression in S. pombe itself might be preferable, while bacterial expression may yield higher quantities suitable for structural studies. When selecting an expression system, researchers should consider the downstream applications and whether post-translational modifications are critical for the protein's function.

How can researchers verify the identity and purity of recombinant SPCC1620.07c?

Verification of recombinant SPCC1620.07c identity and purity typically involves multiple analytical methods. SDS-PAGE can be used to confirm the molecular weight (approximately 37.5 kDa based on the amino acid sequence provided) . Western blotting with antibodies specific to either the protein itself or to any fusion tags can verify identity. Mass spectrometry provides the most definitive confirmation of protein identity through peptide fingerprinting. For purity assessment, size exclusion chromatography or high-performance liquid chromatography (HPLC) can be employed. Additionally, functional assays specific to lunapark proteins should be considered to verify not just the protein's presence but its biological activity.

What is known about the function of lunapark homolog in S. pombe compared to other organisms?

The lunapark protein family is generally involved in endoplasmic reticulum (ER) network formation and maintenance across various organisms. In S. pombe specifically, the lunapark homolog encoded by SPCC1620.07c likely plays a role in ER morphology regulation, though detailed functional characterization in this organism appears limited based on the available search results.

Comparative studies between S. pombe and other model organisms are particularly valuable since S. pombe shares more common features with humans than S. cerevisiae does, including gene structures and chromatin dynamics . The significant evolutionary distance between S. pombe and S. cerevisiae suggests that conserved processes between both yeasts are likely to be conserved in mammals as well. Therefore, investigating lunapark function in S. pombe provides an opportunity to understand evolutionary conservation of ER network regulation mechanisms.

What experimental approaches can be used to study SPCC1620.07c function in vivo?

Several experimental approaches can be employed to study SPCC1620.07c function in vivo, leveraging S. pombe's genetic tractability:

• Gene Deletion/Disruption: Creating SPCC1620.07c knockout strains to observe phenotypic effects, similar to approaches used for studying php2 gene function in S. pombe .

• Fluorescent Tagging: Generating strains expressing fluorescently tagged lunapark to visualize its localization and dynamics in living cells.

• Conditional Expression Systems: Employing regulatable promoters to control SPCC1620.07c expression for studying dose-dependent effects.

• Point Mutations: Introducing specific mutations to identify functional domains and critical residues.

• Synthetic Genetic Interactions: Performing genetic crosses with other mutant strains to identify genetic interactions, potentially revealing functional pathways.

• Chromatin Immunoprecipitation (ChIP): If lunapark has nuclear functions, ChIP can identify DNA binding sites or chromatin interactions, similar to approaches used for studying chromatin-associated proteins in S. pombe .

S. pombe's advantages as a model system make these approaches particularly powerful, as its cellular properties and genetic manipulability facilitate comprehensive functional characterization.

How might SPCC1620.07c interact with other proteins in S. pombe cellular pathways?

Based on studies of lunapark proteins in other organisms, SPCC1620.07c likely participates in protein complexes involved in ER morphogenesis. Potential experimental approaches to identify interaction partners include:

• Co-immunoprecipitation (Co-IP): Using antibodies against tagged SPCC1620.07c to pull down protein complexes, followed by mass spectrometry identification.

• Yeast Two-Hybrid Screening: Employing S. pombe or S. cerevisiae two-hybrid systems to identify direct protein interactions.

• Proximity Labeling: Using BioID or APEX2 fusions to identify proximal proteins in living cells.

• Genetic Interaction Mapping: Performing systematic genetic crosses with deletion/mutation libraries to identify functional relationships.

The transmembrane domains and zinc finger motifs in the lunapark protein sequence suggest potential for both membrane integration and protein or nucleic acid interactions. The presence of CCAAT-binding transcription factor complexes in S. pombe, which regulate mitochondrial function , raises the possibility of functional connections between lunapark and mitochondrial dynamics or functions, particularly at ER-mitochondria contact sites.

What are the challenges in structural characterization of recombinant SPCC1620.07c?

The structural characterization of recombinant SPCC1620.07c presents several challenges:

• Membrane Protein Properties: Lunapark proteins typically contain transmembrane domains, making them difficult to solubilize while maintaining native conformation.

• Protein Stability: The amino acid sequence contains multiple regions predicted to be intrinsically disordered, which may hinder crystallization.

• Expression and Purification: Obtaining sufficient quantities of properly folded protein with correct post-translational modifications may require optimization of expression systems.

• Structural Techniques Selection: Different regions of the protein may require different structural biology approaches:

  • X-ray crystallography for ordered domains

  • NMR for flexible regions

  • Cryo-EM for larger assembled complexes

• Functional Validation: Ensuring that any structural information obtained correlates with functional properties in vivo.

To address these challenges, researchers might consider expressing individual domains separately, employing fusion partners to enhance solubility, or using detergent screening to identify optimal conditions for membrane domain solubilization.

What are the optimal conditions for functional assays with recombinant SPCC1620.07c?

Functional assays for recombinant SPCC1620.07c should be designed based on its predicted roles in ER morphology and membrane dynamics. Optimal conditions typically include:

Buffer Composition:

• pH 7.0-7.5 (physiological range for S. pombe)

• 150 mM NaCl (for ionic strength)

• 1-5 mM MgCl₂ (for potential enzymatic activities)

• 1 mM DTT or 5 mM β-mercaptoethanol (reducing agents to maintain cysteine residues)

In vitro Membrane Interaction Assays:

• Liposome composition should mimic ER membranes (higher phosphatidylcholine content)

• Temperature maintained at 30°C (optimal for S. pombe proteins)

• Addition of GTP or ATP if energy-dependent processes are suspected

For functional comparisons between different protein preparations, standardized activity assays should be developed, potentially measuring membrane tubulation, network formation, or binding to known interaction partners.

How can researchers generate specific antibodies against SPCC1620.07c for immunological studies?

Generating specific antibodies against SPCC1620.07c requires careful antigen design and validation:

• Antigen Selection:

  • Analyze the protein sequence to identify unique, surface-exposed epitopes

  • Consider using either the full-length recombinant protein or synthetic peptides corresponding to unique regions

  • Avoid transmembrane domains as they are typically poor immunogens

• Immunization Strategy:

  • Use purified recombinant SPCC1620.07c with the amino acid sequence provided in the search results

  • Consider KLH or BSA conjugation for peptide antigens

  • Follow standard immunization protocols with adjuvants appropriate for the selected animal model

• Validation Tests:

  • Western blot against recombinant protein and S. pombe cell lysates

  • Immunoprecipitation efficiency testing

  • Immunofluorescence in wild-type vs. knockout strains

  • Pre-adsorption controls with immunizing antigen

• Cross-Reactivity Assessment:

  • Test against lysates from related species to determine specificity

  • Perform epitope mapping to confirm antibody binding regions

The specific amino acid sequence of SPCC1620.07c provided in search result can guide epitope selection, focusing on unique regions to minimize cross-reactivity with other S. pombe proteins.

What comparative approaches can be used to study evolutionary conservation of lunapark function?

Studying the evolutionary conservation of lunapark function requires systematic comparative approaches:

• Sequence Analysis:

  • Multiple sequence alignment of lunapark homologs from diverse species

  • Identification of conserved domains and motifs

  • Phylogenetic analysis to trace evolutionary relationships

• Complementation Studies:

  • Express SPCC1620.07c in S. cerevisiae or mammalian lunapark mutants to test functional complementation

  • Similar approaches have been successful with other S. pombe proteins, as demonstrated by the functional complementation of S. cerevisiae hap2 mutant with S. pombe php2

• Domain Swap Experiments:

  • Create chimeric proteins with domains from different species to identify functionally critical regions

  • Test these chimeras in appropriate knockout/mutant backgrounds

• Conserved Interaction Network Mapping:

  • Compare protein interaction networks across species using orthologous bait and prey proteins

  • Identify core conserved interactions versus species-specific ones

This comparative approach leverages S. pombe's position as an evolutionary intermediate between higher eukaryotes and S. cerevisiae, as S. pombe shares more common features with humans including gene structures and chromatin dynamics .

How should researchers interpret subcellular localization patterns of SPCC1620.07c?

When interpreting subcellular localization of SPCC1620.07c in S. pombe, researchers should consider:

• Expected ER Localization Patterns:

  • Lunapark proteins typically localize to ER tubule junctions

  • In S. pombe, the ER network has distinct characteristics compared to other yeasts

• Colocalization Analysis:

  • Compare with known ER markers (e.g., Sey1, Rtn1)

  • Quantify colocalization using Pearson's or Mander's coefficients

  • Analyze in different cell cycle stages (S. pombe's cell cycle is particularly well-characterized)

• Dynamic Studies:

  • FRAP (Fluorescence Recovery After Photobleaching) to assess protein mobility

  • Time-lapse imaging during cell cycle progression or stress conditions

• Interpretation Framework:

• Artifacts Consideration:

  • Tag-induced mislocalization

  • Overexpression effects

  • Fixation artifacts in immunofluorescence

S. pombe's rod shape and predictable growth pattern make it particularly suitable for quantitative image analysis of protein localization .

What are common pitfalls in protein-protein interaction studies with SPCC1620.07c and how to overcome them?

Protein-protein interaction studies with membrane proteins like SPCC1620.07c present several challenges:

• False Negatives in Yeast Two-Hybrid:

  • Membrane proteins often fail to properly localize to the nucleus

  • Solution: Use split-ubiquitin or membrane-based two-hybrid systems specifically designed for membrane proteins

• Detergent-Induced Artifacts in Co-IP:

  • Harsh detergents can disrupt genuine interactions

  • Solution: Screen multiple mild detergents (digitonin, DDM, CHAPS) at different concentrations

• Overexpression Effects:

  • Non-physiological interactions due to protein abundance

  • Solution: Use endogenous tagging approaches or controlled expression systems

• Cross-Linking Artifacts:

  • Non-specific cross-linking can suggest false interactions

  • Solution: Titrate cross-linker concentrations and include appropriate controls

• Troubleshooting Decision Tree:

• Validation Framework:

  • Confirm interactions by multiple independent methods

  • Demonstrate biological relevance through functional assays

  • Map interaction domains through truncation experiments

How can researchers address solubility and stability issues with recombinant SPCC1620.07c?

Addressing solubility and stability issues with recombinant SPCC1620.07c requires systematic optimization:

• Expression System Selection:

  • If bacterial expression yields insoluble protein, consider eukaryotic systems

  • S. pombe expression may provide native-like modifications

• Fusion Tag Optimization:

  • Test solubility-enhancing tags (MBP, SUMO, GST)

  • Compare N-terminal versus C-terminal tag placement

• Buffer Optimization Matrix:

• Domain-Based Approach:

  • Express soluble domains separately

  • Design constructs based on secondary structure predictions

• Co-expression Strategies:

  • Co-express with known binding partners

  • Include chaperones to assist folding

• Stability Monitoring:

  • Develop thermal shift assays to quantify stability improvements

  • Monitor activity retention over time under different conditions

For the specific amino acid sequence provided , analysis of hydrophobicity profiles can guide construct design by identifying transmembrane regions that might require special solubilization strategies.

How might SPCC1620.07c function be integrated with S. pombe cell cycle regulation?

S. pombe has been instrumental in cell cycle research , offering opportunities to investigate potential connections between lunapark function and cell cycle regulation:

• Cell Cycle-Dependent Regulation:

  • Analyze SPCC1620.07c expression and protein levels throughout the cell cycle

  • Examine post-translational modifications in synchronized cultures

  • Study localization patterns in different cell cycle phases

• ER Dynamics During Cell Division:

  • The ER undergoes significant remodeling during mitosis

  • SPCC1620.07c may play roles in ER inheritance or reestablishment

• Potential Functional Connections:

• Integration with Known Cell Cycle Regulators:

  • Test genetic interactions with cell cycle mutants (cdc mutants)

  • Investigate effects of cell cycle arrest on SPCC1620.07c function

S. pombe's well-characterized cell cycle and the availability of numerous cell cycle mutants make it an ideal system for investigating these potential functional connections .

What roles might SPCC1620.07c play in stress response pathways in S. pombe?

The ER is a major sensor and responder to cellular stress, suggesting potential roles for SPCC1620.07c in stress response:

• ER Stress Response:

  • Investigate SPCC1620.07c expression during ER stress (tunicamycin treatment, DTT)

  • Examine knockout phenotypes under stress conditions

  • Test genetic interactions with known UPR components

• Oxidative Stress Connection:

  • The zinc finger motifs in lunapark may function as redox sensors

  • Test redox-dependent changes in protein function or localization

• Systematic Stress Response Analysis:

• Comparative Analysis:

  • Compare SPCC1620.07c stress functions with those of homologs in other organisms

  • S. pombe provides a valuable evolutionary perspective between mammals and S. cerevisiae

• Systems Biology Approach:

  • Genome-wide screens for genetic interactions under stress conditions

  • Transcriptome analysis of knockout strains during stress response

This research direction leverages S. pombe's robust stress response pathways and their relevance to human cellular stress mechanisms .