SHMT2 Antibody

What is SHMT2 and why is it significant in cancer research?

SHMT2 (serine hydroxymethyltransferase 2, mitochondrial) catalyzes the conversion of serine to glycine with concurrent production of 5,10-methylenetetrahydrofolate, an essential intermediate for purine biosynthesis . This enzyme plays critical roles in:

• One-carbon metabolism essential for cellular biosynthetic processes

• Mitochondrial thymidylate biosynthesis pathway (preventing uracil accumulation in mtDNA)

• Mitochondrial translation through production of 5,10-methylenetetrahydrofolate

• Deubiquitination of target proteins as component of the BRISC complex

Selection criteria should be based on your experimental requirements:

Monoclonal Antibodies (e.g., 67980-1-Ig, E7F4Q):

• Provide higher specificity for single epitopes

• Offer excellent lot-to-lot consistency

• Typically used when reproducibility across experiments is critical

• Example: Mouse monoclonal 67980-1-Ig shows high specificity with WB dilutions up to 1:50000

Polyclonal Antibodies (e.g., 11099-1-AP, ab224427):

• Recognize multiple epitopes, potentially providing higher sensitivity

• May detect SHMT2 in various conformational states

• Better for applications like IHC where antigen retrieval may affect epitope structure

• Example: Rabbit polyclonal ab224427 performs well across WB, IHC-P, and ICC applications

What are the validated methodologies for SHMT2 antibody-based detection in tissue samples?

Immunohistochemistry protocols for SHMT2 detection require specific optimization:

• Antigen Retrieval Methods:

  • Primary recommendation: TE buffer (pH 9.0)

  • Alternative method: Citrate buffer (pH 6.0)

• Validated Tissue Types:

  • Normal tissues: Human liver, brain, lymph node, duodenum

  • Cancer tissues: Human lung adenocarcinoma, breast cancer, cervical cancer, colon cancer

• Interpretation Guidelines:

  • SHMT2 typically shows mitochondrial localization

  • Elevated SHMT2 expression observed in tissues with high oxidative metabolism (liver, brain)

  • Comparative analysis shows significantly higher expression in various cancer tissues versus matched normal tissues

How can SHMT2 expression be reliably quantified in Western blotting experiments?

Step-by-step methodology:

• Sample Preparation:

  • Use RIPA buffer with protease inhibitors for total protein extraction

  • For mitochondrial-specific analysis, perform mitochondrial fraction isolation

• Electrophoresis Considerations:

  • Expected molecular weight: 52-56 kDa

  • Validated positive controls: HEK-293, HeLa, HepG2, Jurkat cells

• Transfer and Detection:

  • Efficient transfer time: 60-90 minutes at 100V for proteins in this molecular weight range

  • Blocking: 5% non-fat milk or BSA in TBST (1 hour at room temperature)

  • Primary antibody incubation: Overnight at 4°C with optimized dilution (1:1000-1:6000 recommended for most SHMT2 antibodies)

• Quantification Methods:

  • Use housekeeping controls appropriate for subcellular fraction (β-actin for total lysate; VDAC/COX IV for mitochondrial fractions)

  • Analyze band intensities using ImageJ or similar software

  • Calculate relative expression using densitometric analysis normalized to loading controls

How does SHMT2 correlate with immune infiltration in cancer, and which methodologies best demonstrate this relationship?

Research has established significant correlations between SHMT2 expression and tumor-infiltrating lymphocytes in lung adenocarcinoma :

Analytical Approaches:

• Bioinformatic Analysis:

  • Use TIMER database (https://cistrome.shinyapps.io/timer/) to analyze correlations between SHMT2 expression and immune infiltration across cancer types

  • Apply TISIDB database to investigate relationships between SHMT2 and specific immune cell populations

• Experimental Validation:

  • Perform multiplex immunofluorescence with SHMT2 antibodies and immune cell markers

  • Conduct flow cytometry on dissociated tumor samples to correlate SHMT2 levels with immune populations

Key Findings:
The relationship between SHMT2 expression and tumor-infiltrating lymphocytes in LUAD suggests potential immunomodulatory functions, which could inform immunotherapy approaches .

What strategies can resolve cross-reactivity issues when using SHMT2 antibodies in multi-protein detection systems?

When encountering cross-reactivity challenges:

• Antibody Selection Strategies:

  • Choose epitope-specific antibodies targeting non-conserved regions between SHMT1 and SHMT2

  • Consider monoclonal antibodies with validated specificity (e.g., E7F4Q)

  • For multi-protein detection, select antibodies raised in different host species to enable simultaneous detection

• Validation Approaches:

  • Implement SHMT2 knockdown/knockout controls to confirm specificity

  • Use recombinant SHMT2 protein as a positive control

  • Perform peptide competition assays to confirm epitope specificity

• Optimization Techniques:

  • Adjust antibody concentration to minimize non-specific binding

  • Modify blocking conditions (5% BSA may reduce background compared to milk for some applications)

  • Increase washing stringency with higher salt concentrations in TBST

How can researchers effectively detect SHMT2 in mitochondrial fractions while preserving native protein complexes?

SHMT2 functions within a tetrameric complex providing one-carbon units for cellular biosynthesis . To analyze these complexes:

Recommended Protocol:

• Gentle Mitochondrial Isolation:

  • Use sucrose gradient centrifugation rather than detergent-based methods

  • Maintain samples at 4°C throughout processing

  • Add protease inhibitors to prevent complex degradation

• Native Complex Analysis:

  • Employ Blue Native PAGE to preserve protein-protein interactions

  • Use mild detergents (digitonin 0.5-1%) for solubilization

  • Apply non-denaturing conditions during sample preparation

• Detection Methods:

  • Transfer to PVDF membranes using specialized native transfer conditions

  • Probe with validated SHMT2 antibodies (1:1000-1:5000 dilution)

  • Consider two-dimensional electrophoresis (BN-PAGE followed by SDS-PAGE) to resolve complex components

• Co-immunoprecipitation:

  • Use anti-SHMT2 antibodies validated for IP applications (e.g., E7F4Q at 1:50 dilution)

  • Analyze co-precipitated proteins to identify complex components

What are the most effective methods to validate SHMT2 antibody specificity?

A comprehensive validation approach includes:

• Genetic Validation:

  • SHMT2 knockdown/knockout using siRNA or CRISPR-Cas9

  • Overexpression of tagged SHMT2 constructs

  • Multiple published studies have used these approaches to validate antibody specificity

• Biochemical Validation:

  • Peptide competition assays using the immunizing peptide

  • Pre-adsorption tests with recombinant SHMT2 protein

  • Testing across multiple cell lines with known SHMT2 expression patterns

• Cross-Platform Validation:

  • Confirm findings using orthogonal detection methods (WB, IHC, IF)

  • Compare results from different antibody clones targeting distinct epitopes

  • Correlation of protein detection with mRNA expression data

How can researchers distinguish between SHMT1 and SHMT2 isoforms in experimental systems?

Distinguishing between these closely related isoforms requires specific methodological approaches:

• Antibody Selection:

  • Choose antibodies targeting N-terminal regions where sequence divergence is greatest between isoforms

  • Antibodies such as ABIN2782502 target SHMT2-specific N-terminal peptide sequences

• Subcellular Fractionation:

  • SHMT2 is primarily mitochondrial, while SHMT1 is cytosolic

  • Perform proper subcellular fractionation followed by Western blotting

  • Use compartment-specific markers to verify fraction purity (e.g., VDAC for mitochondria, GAPDH for cytosol)

• Molecular Approaches:

  • RT-qPCR with isoform-specific primers

  • Mass spectrometry analysis of tryptic peptides unique to each isoform

  • Immunofluorescence with co-localization studies using mitochondrial markers

• Experimental Controls:

  • Include recombinant SHMT1 and SHMT2 proteins as specificity controls

  • Use cell lines with known differential expression of SHMT1/SHMT2

What strategies are recommended for optimizing immunohistochemical detection of SHMT2 in formalin-fixed tissues?

Optimizing IHC protocols for SHMT2 detection requires systematic approach:

• Antigen Retrieval Optimization:

  • Compare heat-induced epitope retrieval methods:

    • Primary recommendation: TE buffer pH 9.0

    • Alternative: Citrate buffer pH 6.0

  • Test multiple retrieval times (10-30 minutes)

• Antibody Dilution Series:

  • Test serial dilutions (starting recommendations):

    • Polyclonal antibodies: 1:250-1:1000

    • Monoclonal antibodies: 1:650-1:2600

  • Include positive control tissues with known SHMT2 expression (liver, colon cancer)

• Detection System Selection:

  • For low expression: Use signal amplification systems (e.g., TSA)

  • For standard detection: HRP-polymer systems offer good signal-to-noise ratio

  • For multiplex studies: Consider fluorescent secondary antibodies

• Validation Controls:

  • Include isotype controls at equivalent concentrations

  • Use tissues with known differential expression (normal vs. cancer)

  • Consider peptide blocking controls for polyclonal antibodies

How can SHMT2 antibodies be utilized to investigate metabolic reprogramming in cancer?

SHMT2 plays crucial roles in cancer metabolic pathways:

• Methodological Approaches:

  • Combine SHMT2 immunodetection with metabolic flux analysis

  • Correlate SHMT2 expression with serine/glycine metabolism markers

  • Use dual-staining approaches to co-localize SHMT2 with mitochondrial metabolic enzymes

• Technical Considerations:

  • For tissue analysis: Multiplex IHC/IF with metabolic markers

  • For cell culture: Correlate SHMT2 expression with metabolite profiling

  • For clinical samples: Combine tissue analysis with patient metabolomics data

• Research Applications:

  • Investigate SHMT2's role in providing one-carbon units for nucleotide synthesis

  • Analyze SHMT2 expression in hypoxic tumor regions where its activity becomes critical

  • Examine SHMT2-dependent metabolic vulnerabilities as potential therapeutic targets

What experimental design best demonstrates SHMT2's role as a prognostic biomarker in lung adenocarcinoma?

Based on evidence showing SHMT2 as a potential prognostic biomarker in LUAD :

Recommended Experimental Design:

• Patient Cohort Analysis:

  • Select statistically meaningful cohort size with adequate follow-up data

  • Stratify patients based on clinical parameters (stage, treatment, etc.)

  • Perform tissue microarray analysis with validated SHMT2 antibodies

• Expression Analysis Methods:

  • Quantitative IHC scoring (H-score or Allred system)

  • Digital pathology with automated quantification

  • Correlation with SHMT2 mRNA expression data

• Statistical Analysis Approaches:

  • Kaplan-Meier survival analysis with log-rank test for significance

  • Multivariate Cox proportional hazard regression to assess independent prognostic value

  • Hazard ratio calculation with 95% confidence intervals

• Validation Strategy:

  • Validate findings in independent patient cohorts

  • Correlate with other established biomarkers

  • Perform subgroup analysis based on molecular subtypes