Recombinant Vitis vinifera CASP-like protein GSVIVT00013434001 (GSVIVT00013434001)

What is the molecular structure of GSVIVT00013434001 and how does it compare to other CASP-like proteins?

GSVIVT00013434001 belongs to the CASP-like (CASPL) protein family, characterized by four transmembrane spans. Based on structural analyses of CASP proteins, it likely forms a membrane scaffold similar to other CASPLs. The protein contains transmembrane domains that are highly conserved across plant species, with the second extracellular loop (EL2) showing significant conservation while the first extracellular loop (EL1) typically exhibits lower conservation .

In membrane localization experiments, CASPLs demonstrate high stability in their membrane domains, which suggests that GSVIVT00013434001 likely forms a stable transmembrane scaffold. The protein would be expected to localize to the plasma membrane, as demonstrated with other CASP-like proteins such as ClCASPL from watermelon .

How can I determine if GSVIVT00013434001 contains the conserved nine-amino acid signature found in other CASP proteins?

To determine if GSVIVT00013434001 contains the conserved nine-amino acid signature (ESLPFFTQF) found in some CASP proteins, implement the following methodological approach:

• Perform a multiple sequence alignment of GSVIVT00013434001 with confirmed CASP proteins that possess this signature

• Specifically examine the first extracellular loop (EL1) region where this signature is typically located

• Use alignment tools such as Clustal Omega or MUSCLE for the analysis

• Confirm findings through site-directed mutagenesis experiments

The presence of this signature could indicate functional similarity to CASPs found in spermatophytes, which are specifically involved in endodermal function. Its absence might suggest divergent functionality more similar to general CASPLs found across broader plant lineages .

What are the predicted post-translational modifications of GSVIVT00013434001?

While specific post-translational modifications of GSVIVT00013434001 have not been directly characterized in the literature, analysis of CASP-like proteins suggests several potential modifications:

Experimental validation of these predictions would require mass spectrometry analysis of purified protein, with and without phosphatase treatment, combined with site-directed mutagenesis of predicted modification sites .

What is the tissue-specific expression pattern of GSVIVT00013434001 in Vitis vinifera?

Based on expression patterns observed for other CASP-like proteins, GSVIVT00013434001 likely shows tissue-specific expression that corresponds to its physiological function. Studies of orthologous CASP-like proteins demonstrate that promoter analysis using reporter genes (such as GUS or fluorescent proteins) can effectively map expression patterns.

For example, the Arabidopsis ortholog AtCASPL4C1 is widely expressed across various organs and is inducible under cold stress conditions . To determine the specific expression pattern of GSVIVT00013434001:

• Clone the 2kb upstream region of GSVIVT00013434001

• Create a promoter-reporter fusion construct (using GUS or fluorescent protein)

• Transform Vitis vinifera tissues or use heterologous expression in Arabidopsis

• Analyze tissue sections at different developmental stages and under various stress conditions

This approach would provide a comprehensive understanding of when and where GSVIVT00013434001 is expressed in grapevine tissues .

How can I verify the subcellular localization of GSVIVT00013434001?

To verify the subcellular localization of GSVIVT00013434001, implement this methodological workflow:

• Create a C-terminal or N-terminal fusion with a fluorescent protein (GFP, mCherry)

• Express the fusion protein in:

  • Heterologous systems (tobacco leaves via Agrobacterium-mediated transformation)

  • Vitis vinifera cell suspensions

  • Arabidopsis as a model system

• Analyze using confocal microscopy alongside appropriate membrane markers

• Perform co-localization experiments with known plasma membrane markers

• Conduct cellular fractionation followed by Western blot analysis as biochemical confirmation

Based on findings from other CASP-like proteins, GSVIVT00013434001 would be expected to localize to the plasma membrane. For example, ClCASPL-GFP from watermelon was found to localize in the plasma membrane , suggesting that GSVIVT00013434001 would behave similarly .

What experimental design would best determine if GSVIVT00013434001 functions in stress response?

To determine if GSVIVT00013434001 functions in stress response, particularly cold stress as suggested by studies of orthologous proteins, implement the following experimental design:

This multi-faceted approach would provide robust evidence for stress response function. The experimental design should include at least three biological replicates and appropriate statistical analysis. Based on findings for AtCASPL4C1, which showed altered cold tolerance when knocked out , you might expect GSVIVT00013434001 to similarly influence stress responses in grapevine .

How should I design experiments to investigate protein-protein interactions involving GSVIVT00013434001?

To investigate protein-protein interactions involving GSVIVT00013434001, follow this comprehensive experimental approach:

• In vitro methods:

  • Pull-down assays using purified recombinant GSVIVT00013434001

  • Co-immunoprecipitation from plant extracts using specific antibodies

• In vivo methods:

  • Yeast two-hybrid screening against a Vitis vinifera cDNA library

  • Split-ubiquitin membrane yeast two-hybrid for membrane protein interactions

  • Bimolecular Fluorescence Complementation (BiFC) in planta

  • Förster Resonance Energy Transfer (FRET) analysis

• Mass spectrometry approaches:

  • Proximity-dependent biotin identification (BioID)

  • Tandem affinity purification coupled with mass spectrometry

Given that CASP proteins form membrane domains and interact with lignin polymerization machinery in Arabidopsis , focus on investigating interactions with cell wall modification enzymes and other membrane proteins. This approach will help determine if GSVIVT00013434001 participates in similar protein complexes in grapevine .

What variables must be controlled when analyzing the effects of GSVIVT00013434001 overexpression in transgenic plants?

When analyzing the effects of GSVIVT00013434001 overexpression in transgenic plants, the following variables must be carefully controlled:

Based on studies of other CASP-like proteins, particular attention should be paid to growth parameters, flowering time, and stress responses, as these were significantly altered in AtCASPL4C1 knockout lines . This comprehensive approach ensures reliable data interpretation and minimizes experimental artifacts .

How can CRISPR-Cas9 genome editing be optimized for studying GSVIVT00013434001 function in Vitis vinifera?

Optimizing CRISPR-Cas9 genome editing for studying GSVIVT00013434001 function in Vitis vinifera requires addressing several grape-specific challenges:

• sgRNA design considerations:

  • Target conserved regions within exons, particularly in the transmembrane domains

  • Design multiple sgRNAs targeting different exons

  • Verify specificity against the Vitis vinifera genome to minimize off-target effects

  • Optimize for grapevine codon usage

• Delivery method optimization:

  • Agrobacterium-mediated transformation of embryogenic calli

  • Protoplast transformation for initial validation

  • Ribonucleoprotein (RNP) complex delivery to reduce off-target effects

• Selection and verification:

  • Design PCR-based screening for detecting indels

  • Implement T7 endonuclease assay or TIDE analysis

  • Sequence verification of mutations

  • RT-qPCR and Western blot confirmation of knockout

• Phenotypic analysis:

  • Focus on stress tolerance parameters based on findings with AtCASPL4C1

  • Examine growth rate, biomass, and flowering time

  • Analyze membrane domain formation using fluorescent markers

This methodical approach will help overcome the difficulties of grapevine transformation while providing robust functional data on GSVIVT00013434001 .

What are the most appropriate heterologous expression systems for producing recombinant GSVIVT00013434001 for structural studies?

For structural studies of recombinant GSVIVT00013434001, consider these heterologous expression systems, each offering specific advantages:

For membrane proteins like GSVIVT00013434001, insect cell or plant-based expression systems often provide better structural integrity. Since transmembrane domains are crucial for CASP protein function , careful detergent selection during purification is essential to maintain the native conformation. Consider implementing Styrene Maleic Acid Lipid Particles (SMALPs) for membrane extraction to preserve the lipid environment .

How might comparative genomics inform the evolution of GSVIVT00013434001 function across plant species?

Comparative genomics provides valuable insights into the evolution of GSVIVT00013434001 function through these methodological approaches:

• Phylogenetic analysis:

  • Construct phylogenetic trees including CASP and CASPL proteins from diverse plant species

  • Map the emergence of key functional domains, particularly the nine-amino acid signature (ESLPFFTQF) found in spermatophyte CASPs

  • Examine selection pressure on different protein domains using dN/dS ratios

• Synteny analysis:

  • Investigate genomic context conservation around GSVIVT00013434001 orthologs

  • Identify co-evolved gene clusters that might indicate functional relationships

• Domain architecture comparison:

  • Analyze conservation of transmembrane domains and loop regions

  • Identify lineage-specific insertions/deletions that might confer specialized functions

• Expression pattern evolution:

  • Compare expression profiles of orthologs across species

  • Identify regulatory element conservation or divergence

Based on existing research, CASP-like proteins are found across all major divisions of land plants and green algae, with CASP proteins proper (containing the nine-amino acid signature) appearing more recently in spermatophytes . This evolutionary trajectory suggests that GSVIVT00013434001 might represent an adaptation specific to vascular plants, potentially related to specialized membrane domain formation or stress response functions .

What are common pitfalls when expressing membrane proteins like GSVIVT00013434001 in heterologous systems?

When expressing membrane proteins like GSVIVT00013434001 in heterologous systems, researchers frequently encounter these challenges and solutions:

For CASP-like proteins specifically, mutagenesis studies have shown that certain conserved residues in transmembrane domains (such as the Asp residue in TM3) may be essential for correct protein folding . Therefore, preserving these critical residues during construct design is essential .

How can I resolve data inconsistencies when comparing GSVIVT00013434001 knockout phenotypes with overexpression studies?

Resolving data inconsistencies between knockout and overexpression studies requires a systematic troubleshooting approach:

• Verify genetic modifications:

  • Confirm knockout is complete through genomic PCR, RT-PCR, and Western blotting

  • Quantify overexpression levels across independent lines

  • Ensure no compensatory expression of homologous genes

• Address dosage effects:

  • Generate and analyze multiple independent transgenic lines with varying expression levels

  • Create an expression gradient using inducible promoters

  • Consider dominant-negative effects in overexpression lines

• Examine developmental timing:

  • Conduct time-course analyses to distinguish immediate vs. long-term effects

  • Implement tissue-specific or inducible systems to bypass developmental adaptations

• Control for genetic background:

  • Use identical background for both knockout and overexpression

  • Perform complementation tests to confirm phenotype causality

• Consider protein interactions:

  • Overexpression may sequester interacting partners

  • Knockout may destabilize protein complexes

Based on studies of AtCASPL4C1, knockout lines showed opposite phenotypes to overexpression lines regarding cold tolerance , suggesting a negative regulatory role. Similar opposing effects might be expected with GSVIVT00013434001, where inconsistencies could actually reflect biological reality rather than experimental error .

What strategies can overcome challenges in analyzing membrane domain formation by GSVIVT00013434001?

Analyzing membrane domain formation by GSVIVT00013434001 presents unique challenges that can be addressed through these specialized approaches:

• Advanced microscopy techniques:

  • Super-resolution microscopy (STORM, PALM) to visualize domains below diffraction limit

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

  • Single-particle tracking to analyze dynamic behavior

  • Total Internal Reflection Fluorescence (TIRF) microscopy for improved membrane visualization

• Membrane isolation strategies:

  • Detergent-resistant membrane fractionation

  • Density gradient centrifugation to isolate membrane microdomains

  • Atomic Force Microscopy of isolated membranes

• Protein-lipid interaction analysis:

  • Lipidomics of membrane domains containing GSVIVT00013434001

  • In vitro reconstitution with defined lipid compositions

  • Lipid binding assays to identify specific interactions

• Functional probes for domain integrity:

  • Fluorescent lipid analogs to test barrier function

  • Electrophysiology measurements across membranes

  • Protein diffusion analyses using photo-switchable fluorescent proteins

CASP proteins form membrane scaffolds that can restrict diffusion of other membrane components . Therefore, measuring the diffusion barriers created by GSVIVT00013434001 would provide functional evidence of domain formation, similar to how the Casparian strip membrane domain restricts diffusion in plant endodermis .