PME12 Antibody
Description
Introduction to PME12 Antibody
PME12 Antibody targets the PME12 protein, a member of the pectin methylesterase family that regulates pectin esterification status in plant cell walls. Pectin modification influences cell wall rigidity and pathogen interaction dynamics . PME12 is implicated in plant immunity, as its expression is upregulated during pathogen challenges .
Pathogen Response and Immune Function
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Upregulation During Infection: PME12 expression increases after inoculation with Pseudomonas syringae (Pma ES4326), as confirmed by qRT-PCR .
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Enhanced Susceptibility in Mutants:
PME Activity Dynamics
| Condition | PME Activity in pme12 Mutants vs. Wild-Type |
|---|---|
| Baseline (no pathogen) | Unaltered |
| Post-Pma ES4326 infection | Increased in 2/3 pme12 alleles |
This indicates compensatory mechanisms or redundancy among PME genes during pathogen response .
Applications in Research
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Immune Pathway Analysis: Identifies PME12's role in cell wall-mediated defense against bacterial pathogens .
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Genetic Interaction Studies: Used to create double/triple mutants (e.g., pme12 pme41) to dissect functional redundancy .
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Activity Assays: Measures total PME activity in plant tissues under pathogen stress .
Limitations and Future Directions
Product Specs
Target Background
Q&A
Basic Research Questions
What methodologies are validated for detecting PME12 autoantibodies in clinical samples?
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Sensitivity: 95% (21/22 anti-PL-12 sera detected)
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Specificity: 100% (0/300 control sera) .
The recombinant antigen is produced via immunological screening of a HeLa cDNA library, followed by purification and validation against autoimmune sera .
What is the clinical relevance of PME12 autoantibodies?
PME12 autoantibodies target alanyl-tRNA synthetase (PL-12) and are strongly associated with idiopathic inflammatory myopathies (e.g., polymyositis). Their detection aids in:
How is the immunoreactive region of PME12 characterized?
Epitope mapping using recombinant PL-12 fragments identified a conformational epitope within aa 730–951, outside the catalytic domain (aa 1–499) . This region is conserved across anti-PL-12 sera, suggesting diagnostic utility despite variability in patient responses.
Advanced Research Questions
How can researchers resolve discrepancies in PME12 detection across methods?
Discrepancies (e.g., ELISA-negative but immunoprecipitation-positive sera) may arise from:
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Low antibody titers near the ELISA cut-off (7,000 U).
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Non-linear epitopes disrupted in recombinant antigens.
Validation strategies: -
Combine ELISA with immunoprecipitation for borderline cases.
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Use synthetic peptides spanning aa 730–951 for epitope confirmation .
What experimental design considerations are critical for epitope mapping studies?
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Antigen fragmentation: Use overlapping recombinant peptides (e.g., GST fusion proteins) to narrow epitope regions .
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Serum selection: Include multiple anti-PL-12 sera to assess epitope conservation (e.g., 3 sera in ).
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Controls: Preabsorb sera with GST or irrelevant proteins to exclude non-specific binding .
How should ELISA cut-offs be optimized for PME12 screening?
| Parameter | Recommendation | Reference |
|---|---|---|
| Cut-off definition | Mean + 3 SD of healthy controls | |
| Validation cohort | 100 healthy, 200 autoimmune (SLE, scleroderma) | |
| Dynamic range | ≥50,000 U for 90% of positive sera |
Data Contradiction Analysis
Why do some PME12-positive sera show weak/no reactivity in ELISA?
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Low-affinity antibodies: May fail to bind immobilized recombinant antigen.
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Post-translational modifications: Native PL-12 in patient sera may carry modifications absent in recombinant proteins.
Mitigation: Augment ELISA with western blotting using native PL-12 extracts .
Methodological Innovations
Can structural proteomics improve PME12 antibody characterization?
Yes. Techniques like hydrogen/deuterium exchange-MS (HDX-MS) and cross-linking-MS can map antibody-antigen interfaces (e.g., applied in therapeutic antibody engineering ). For PME12, these methods could:
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Identify residues critical for self-association or aggregation.
Comparative Data Table
| Method | Sensitivity | Specificity | Throughput | Key Limitation |
|---|---|---|---|---|
| Immunoprecipitation | 100% | 100% | Low | Labor-intensive, requires radiolabeling |
| Recombinant ELISA | 95% | 100% | High | May miss low-titer/ conformational epitopes |
