Recombinant Arabidopsis thaliana C2 domain-containing protein At1g53590 (NTMC2T6.1)

What is Arabidopsis thaliana C2 domain-containing protein At1g53590 (NTMC2T6.1)?

NTMC2T6.1 is a protein encoded by the At1g53590 gene in Arabidopsis thaliana, also known as C2 domain-containing protein At1g53590. It belongs to the N-terminal-TM-C2 domain type 6 protein family. This protein contains 751 amino acids and is characterized by the presence of C2 domains, which are calcium-dependent membrane-targeting modules found in many cellular proteins involved in signal transduction or membrane trafficking. The UniProt accession number for this protein is Q93XX4, and it is also referred to as C2D61_ARATH in some databases .

What is the structural composition of NTMC2T6.1?

NTMC2T6.1 is a full-length protein (1-751 amino acids) containing C2 domains. The protein sequence begins with "MESSLIHHIIIVLLLLWFISSLNRSHAFFYFLALIYLYLVHER..." and continues through to the C-terminus. The C2 domain is a structural motif of approximately 130 amino acids that functions as a calcium-dependent membrane-targeting module in many proteins involved in signal transduction and membrane trafficking. The protein contains multiple phosphorylation sites, particularly on serine residues, which are important for its regulation and function .

What post-translational modifications have been identified for NTMC2T6.1?

Several phosphorylation sites have been identified in NTMC2T6.1 through various studies. These include:

These phosphorylation events are likely involved in regulating the protein's function, potentially in response to various cellular signals or environmental stresses .

How can I effectively express and purify recombinant NTMC2T6.1 for functional studies?

For optimal expression and purification of recombinant NTMC2T6.1, consider the following methodological approach:

• Expression System: E. coli is an established system for expressing this protein. Use an N-terminal His-tag for efficient purification.

• Expression Construct: Clone the full-length coding sequence (1-751 amino acids) into a prokaryotic expression vector with an appropriate promoter and His-tag.

• Protein Purification Protocol:

  • Lyse cells in Tris/PBS-based buffer (pH 8.0)

  • Perform affinity chromatography using Ni-NTA resin

  • Elute with imidazole

  • Conduct size exclusion chromatography to enhance purity

  • Concentrate the protein and add 6% trehalose for stability

  • Lyophilize if long-term storage is needed

• Reconstitution and Storage:

  • Reconstitute lyophilized protein in deionized sterile water to 0.1-1.0 mg/mL

  • Add glycerol to a final concentration of 50% for optimal stability

  • Store working aliquots at 4°C for up to one week

  • For long-term storage, keep at -20°C/-80°C and avoid repeated freeze-thaw cycles

What methods are recommended for studying the phosphorylation dynamics of NTMC2T6.1?

To investigate the phosphorylation dynamics of NTMC2T6.1, researchers should implement a multi-faceted approach:

• Phospho-specific antibodies: Develop antibodies against the known phosphorylation sites (S432, S434, S435, S483, S524, S539, S544, S546, S548, S579, S584) to monitor site-specific phosphorylation under different conditions.

• Mass spectrometry analysis: Perform liquid chromatography-tandem mass spectrometry (LC-MS/MS) after tryptic digestion to identify and quantify phosphorylation sites.

• In vitro kinase assays: Identify the kinases responsible for phosphorylating NTMC2T6.1 using recombinant protein and candidate kinases.

• Phosphomimetic mutations: Create phosphomimetic (S to D/E) and phospho-null (S to A) mutations at key sites to study their functional significance.

• Phosphoproteomics: Conduct differential phosphoproteomic analysis under various stress conditions (salt, drought, ABA treatment) to analyze phosphorylation dynamics in response to environmental stimuli .

What role does NTMC2T6.1 play in plant stress responses?

Based on studies of C2 domain proteins in Arabidopsis and related species, NTMC2T6.1 likely plays a role in abiotic stress responses. Research on related C2 domain proteins (such as GmC2-148 in soybean) has demonstrated significant functions in stress tolerance mechanisms:

• Salt and drought stress responses: C2 domain proteins enhance tolerance to salt and drought stresses.

• Physiological adaptations: Plants with elevated expression of C2 domain proteins show:

  • Delayed leaf rolling under stress conditions

  • Higher proline content (an osmoprotectant)

  • Lower levels of reactive oxygen species (H₂O₂, O₂⁻)

  • Reduced malondialdehyde (MDA) content, indicating less oxidative damage to cell membranes

• Transcriptional regulation: C2 domain proteins appear to influence the expression of several abiotic stress-related marker genes, including COR47, NCDE3, NAC11, WRKY13, DREB2A, MYB84, bZIP44, and KIN1.

• Subcellular localization: NTMC2T6.1 and related proteins are likely localized to the cell membrane, where they may participate in signaling cascades or membrane stabilization during stress conditions .

How can I analyze the functional conservation of NTMC2T6.1 across different plant species?

To investigate the functional conservation of NTMC2T6.1 across plant species, implement the following comprehensive research strategy:

• Phylogenetic analysis:

  • Identify homologs in other plant species using bioinformatic tools (BLAST, HMMER)

  • Construct phylogenetic trees to visualize evolutionary relationships

  • Use tools like MEGA7.0 with 1,000 bootstrap replicates for robust phylogenetic analysis

• Structure-function analysis:

  • Compare domain architectures using CDD, Pfam, and SMART databases

  • Analyze conservation of key functional residues, especially in C2 domains

  • Examine conservation of phosphorylation sites identified in NTMC2T6.1

• Expression pattern comparison:

  • Compare tissue-specific expression patterns of homologs across species

  • Analyze expression changes in response to abiotic stresses (salt, drought, ABA)

• Functional complementation:

  • Express NTMC2T6.1 homologs from different species in Arabidopsis mutants

  • Test whether homologs can rescue the mutant phenotype

  • Quantify stress tolerance parameters (proline content, ROS levels, MDA content)

What approaches can be used to investigate the subcellular localization of NTMC2T6.1?

To determine the subcellular localization of NTMC2T6.1, consider these methodological approaches:

• Fluorescent protein fusion constructs:

  • Generate N- and C-terminal GFP/YFP/RFP fusions with NTMC2T6.1

  • Express in Arabidopsis protoplasts or transgenic plants

  • Visualize using confocal microscopy

  • Co-localize with established organelle markers

• Immunolocalization:

  • Develop specific antibodies against NTMC2T6.1

  • Perform immunofluorescence on fixed plant cells

  • Use gold-labeled secondary antibodies for electron microscopy

• Biochemical fractionation:

  • Isolate subcellular fractions (membrane, cytosol, nucleus)

  • Detect NTMC2T6.1 using Western blotting

  • Compare distribution under normal and stress conditions

• Calcium-dependent localization:

  • Since C2 domains often mediate calcium-dependent membrane binding, analyze localization in the presence of calcium chelators or ionophores

  • Use live-cell imaging to capture dynamic translocation events

How should I design experiments to identify interaction partners of NTMC2T6.1?

For comprehensive identification of NTMC2T6.1 interaction partners, implement a multi-pronged approach:

• Yeast two-hybrid screening:

  • Use NTMC2T6.1 as bait against an Arabidopsis cDNA library

  • Verify positive interactions with targeted yeast two-hybrid assays

  • Create domain deletion variants to map interaction domains

• Co-immunoprecipitation (Co-IP):

  • Express epitope-tagged NTMC2T6.1 in Arabidopsis

  • Perform Co-IP followed by mass spectrometry

  • Validate interactions by reverse Co-IP with candidate partners

• Bimolecular Fluorescence Complementation (BiFC):

  • Fuse NTMC2T6.1 and candidate partners to complementary fragments of a fluorescent protein

  • Express in plant cells and visualize reconstituted fluorescence

  • Map interaction domains through deletion constructs

• Proximity-dependent biotin identification (BioID):

  • Fuse NTMC2T6.1 to a biotin ligase

  • Express in planta and identify biotinylated proteins by mass spectrometry

  • This approach captures transient and weak interactions

• Protein arrays:

  • Probe plant protein arrays with purified NTMC2T6.1

  • Verify interactions using in vitro binding assays

  • Test calcium-dependence of interactions

What methods can be used to study the promoter activity and regulation of NTMC2T6.1 expression?

To investigate the promoter activity and expression regulation of NTMC2T6.1, employ these methodological approaches:

• Promoter sequence analysis:

  • Extract the 1,500 bp upstream region from the ATG start codon

  • Analyze using tools like PLACE to identify cis-acting elements related to abiotic stresses

  • Compare with promoters of other stress-responsive genes

• Promoter-reporter constructs:

  • Clone the NTMC2T6.1 promoter upstream of reporter genes (GUS, LUC)

  • Generate transgenic Arabidopsis lines

  • Analyze reporter activity in different tissues and under various stress conditions

• Chromatin immunoprecipitation (ChIP):

  • Identify transcription factors that bind to the NTMC2T6.1 promoter

  • Perform ChIP-seq to map binding sites at genome-wide scale

  • Validate binding with electrophoretic mobility shift assays (EMSA)

• Expression analysis under stress conditions:

  • Expose plants to various stresses (drought, salt, ABA, high temperature)

  • Collect samples at different time points (0, 1, 2, 4, 8, 12, and 24 h)

  • Perform RT-qPCR to quantify expression changes

  • Correlate expression with physiological responses

How can I analyze the evolutionary relationship of NTMC2T6.1 with other C2 domain proteins?

To analyze evolutionary relationships between NTMC2T6.1 and other C2 domain proteins:

• Sequence retrieval and alignment:

  • Download protein sequences of C2 domain proteins from Phytozome database

  • Retrieve HMM profiles of the C2 domain (PF00168)

  • Perform multiple sequence alignment using ClustalW2

  • Focus on conserved residues within the C2 domain

• Phylogenetic tree construction:

  • Use MEGA7.0 to build trees using the neighbor-joining method

  • Apply 1,000 bootstrap replicates for statistical confidence

  • Analyze clustering patterns to identify evolutionarily related groups

• Gene structure comparison:

  • Compare exon-intron structures of C2 domain genes

  • Analyze intron phases and positions

  • Identify structural variations that correspond to functional divergence

• Domain architecture analysis:

  • Use MEME to identify conserved motifs

  • Compare domain organizations across different C2 proteins

  • Correlate domain architecture with functional specialization

• Synteny and duplication analysis:

  • Map C2 domain genes on chromosomes

  • Use MCScanX to analyze gene duplication events

  • Investigate the contribution of duplication to functional diversification

What bioinformatic tools are most appropriate for predicting the functional domains of NTMC2T6.1?

For comprehensive prediction and analysis of NTMC2T6.1 functional domains, utilize these bioinformatic tools and approaches:

• Domain identification:

  • Conserved Domain Database (CDD) for identifying known functional domains

  • Pfam for family-specific domain annotation

  • SMART for architecture-based domain prediction

  • InterProScan for integrated domain analysis

• Structural prediction:

  • AlphaFold or RoseTTAFold for 3D structure prediction

  • PyMOL or UCSF Chimera for structural visualization

  • PredictProtein for secondary structure analysis

  • MODELLER for homology modeling if structural templates exist

• Functional site prediction:

  • NetPhos for phosphorylation site prediction

  • ELM for linear motif identification

  • PredictNLS for nuclear localization signal detection

  • PredictNES for nuclear export signal identification

• Membrane interaction analysis:

  • TMHMM for transmembrane domain prediction

  • MemBrain for membrane-interacting regions

  • PPM server for protein-membrane interaction modeling

  • OPM database for comparative analysis with known membrane proteins

How do I interpret phosphoproteomic data for NTMC2T6.1 in the context of plant stress responses?

When interpreting phosphoproteomic data for NTMC2T6.1 in the context of stress responses, follow these analytical steps:

• Comparative phosphorylation profiling:

  • Compare phosphorylation patterns under normal versus stress conditions

  • Quantify changes in phosphorylation at specific sites (S432, S434, S435, S483, S524, S539, S544, S546, S548, S579, S584)

  • Correlate phosphorylation changes with stress intensity and duration

• Kinase prediction and networks:

  • Use tools like NetworKIN to predict responsible kinases

  • Construct kinase-substrate networks to identify signaling pathways

  • Analyze co-regulated phosphoproteins for pathway enrichment

• Structure-function correlation:

  • Map phosphorylation sites on predicted 3D structure

  • Assess proximity to functional domains, especially C2 domains

  • Evaluate potential impact on protein-membrane or protein-protein interactions

• Integration with transcriptomic data:

  • Correlate phosphorylation changes with expression of stress-responsive genes

  • Analyze expression of genes encoding interaction partners

  • Identify feedback loops between phosphorylation events and transcriptional regulation

• Physiological correlation:

  • Link phosphorylation patterns to physiological parameters (proline content, ROS levels)

  • Compare with phosphorylation patterns of known stress-responsive proteins

  • Establish temporal relationships between phosphorylation events and stress responses

What are the most promising research areas for understanding NTMC2T6.1 function in plant biology?

The most promising research directions for elucidating NTMC2T6.1 function include:

• Stress signaling integration: Investigating how NTMC2T6.1 integrates multiple stress signals (drought, salt, ABA) and contributes to cross-talk between different stress response pathways.

• Calcium signaling dynamics: Exploring the calcium-dependent membrane binding properties of NTMC2T6.1 and how calcium oscillations affect its localization and function.

• Phosphorylation-dependent regulatory networks: Mapping the kinases and phosphatases that regulate NTMC2T6.1 and how its phosphorylation status affects downstream targets.

• Membrane dynamics and vesicular trafficking: Examining the role of NTMC2T6.1 in membrane reorganization during stress and potential involvement in vesicular trafficking.

• Crop improvement applications: Translating knowledge from Arabidopsis to crop species by identifying and characterizing NTMC2T6.1 orthologs in economically important plants, potentially enhancing their stress resilience .

How can CRISPR-Cas9 technology be applied to study NTMC2T6.1 function in Arabidopsis?

CRISPR-Cas9 technology offers powerful approaches for investigating NTMC2T6.1 function:

• Gene knockout studies:

  • Design sgRNAs targeting exonic regions of NTMC2T6.1

  • Generate complete knockout mutants

  • Analyze phenotypic consequences under normal and stress conditions

  • Assess changes in stress-responsive gene expression

• Domain-specific mutations:

  • Create precise mutations in C2 domains using base editing

  • Target calcium-binding residues to disrupt function

  • Engineer phospho-null or phosphomimetic mutations at key sites

• Promoter editing:

  • Modify cis-regulatory elements in the NTMC2T6.1 promoter

  • Analyze effects on expression patterns under different conditions

  • Identify critical regulatory regions for stress responsiveness

• Tagging for live-cell imaging:

  • Insert fluorescent protein tags at the endogenous locus

  • Maintain native expression levels and regulation

  • Perform live-cell imaging to track dynamics under stress

• Multiplexed editing:

  • Simultaneously target NTMC2T6.1 and related C2 domain genes

  • Overcome functional redundancy issues

  • Create combinatorial mutants to reveal synthetic phenotypes