SOBIR1 Antibody
Description
Role in Immune Signaling
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SOBIR1 Kinase Activity: The antibody confirmed that SOBIR1 phosphorylation is essential for its constitutive immune activity. Studies showed that kinase-active SOBIR1 and BAK1/SERK3 co-receptor are required for immune signaling in A. thaliana and Cf-4/Avr4-mediated resistance in tomato .
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Phosphorylation Dynamics: SOBIR1 phosphorylation is linked to its interaction with BAK1. Co-expression of kinase-dead BAK1 mutants (e.g., D416N) suppresses SOBIR1-mediated immune responses, highlighting their interdependent activation .
Subcellular Localization and Interactions
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Plasma Membrane Microdomains: Immunoblotting revealed two distinct molecular weight forms of SOBIR1 in N. benthamiana, suggesting post-translational modifications. The higher molecular weight form associates with ER-localized proteins like NbRLP1, modulating immune responses .
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CRISPR/Cas9 Validation: The antibody was used to validate SOBIR1 knockout lines in N. benthamiana, demonstrating its necessity for Cf-4/Avr4-triggered hypersensitive response (HR) .
Applications in Plant Immunity Studies
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Western Blot Analysis: The antibody reliably detects SOBIR1 in protein extracts, aiding studies on its expression under pathogen challenge or genetic manipulation .
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Protein-Protein Interaction Studies: Co-immunoprecipitation experiments confirmed SOBIR1’s interaction with RLPs (e.g., Cf-4) and BAK1, elucidating its role in receptor complex activation .
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Functional Characterization: Research using this antibody revealed SOBIR1’s dual role in immunity and development, such as regulating floral organ shedding via endosomal trafficking .
Limitations and Future Directions
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Cross-Reactivity: While effective in A. thaliana and N. benthamiana, reactivity in other species (e.g., soybean) remains predicted and requires validation .
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Phosphorylation-Specific Tools: Current antibodies detect total SOBIR1 but lack specificity for phosphorylated forms, limiting studies on activation dynamics .
Product Specs
Constituents: 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
- AvrPto, a bacterial effector, suppresses SOBIR1-induced cell death in Nicotiana benthamiana. PMID: 28876174
- BAK1 and SOBIR1 interact in planta when BIR1 function is compromised. PMID: 27400831
- SOBIR1 plays a role in both penetration and post-penetration resistance against Magnaporthe oryzae, a fungal pathogen, in Arabidopsis. PMID: 27023441
- Mutations in SOBIR1 suppressed the effects of BAK1 overexpression, highlighting SOBIR1's role as a positive regulator of transmembrane receptors in plants. PMID: 25944825
- SOBIR1 interacts with RLP23, a receptor-like protein. PMID: 24525519
- ER (endoplasmic reticulum) quality control plays a crucial role in the biogenesis of SOBIR1. PMID: 24498907
- The functionality of ReMAX, a receptor-like protein, relies on the presence of SOBIR. PMID: 24384530
- RLP30, BAK1, and SOBIR1/EVR contribute to resistance against necrotrophic fungi. PMID: 24104566
- Studies indicate that SOBIR1/EVR is essential for receptor-like proteins (RLPs)-mediated immunity in plants. PMID: 23716655
- SOBIR1 encodes a receptor-like kinase, functioning as a key regulator in a signal transduction pathway activated in bir1-1 mutants. This pathway constitutively activates defense responses, promoting cell death and disease resistance. PMID: 19616764
Q&A
FAQs for SOBIR1 Antibody in Academic Research
Advanced Research Questions
How to investigate SOBIR1’s role in receptor-like protein (RLP) complex formation?
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Methodology:
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Perform co-immunoprecipitation (Co-IP) with RLPs (e.g., Cf-4, Ve1) in the presence/absence of pathogens. SOBIR1 constitutively associates with RLPs like ELR and requires BAK1/SERK3 for signal amplification .
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Use Förster resonance energy transfer (FRET) or bimolecular fluorescence complementation (BiFC) to visualize SOBIR1-RLP interactions in planta .
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Critical consideration: SOBIR1 stability depends on RLP interaction; monitor protein turnover via cycloheximide chase assays .
How to resolve contradictory data on SOBIR1’s dual role in immunity and cell death?
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Context-dependent analysis:
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Experimental design: Use tissue-specific promoters or inducible systems (e.g., dexamethasone) to titrate SOBIR1 expression levels and separate immunity from cell death .
How to study SOBIR1 phosphorylation dynamics during immune signaling?
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Tools:
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Challenge: Phosphorylation status may vary by subcellular localization (e.g., plasma membrane microdomains vs. endocytosed vesicles) .
Data Tables
Table 1: SOBIR1 Antibody Performance Across Species
| Species | Confirmed Reactivity | Predicted Reactivity | Observed MW (kDa) |
|---|---|---|---|
| A. thaliana | Yes | N/A | 71 |
| N. benthamiana | Yes | N/A | 71 |
| S. lycopersicum | No | Yes | – |
| G. max | No | Yes | – |
Table 2: SOBIR1 Functional Interactions in Pathogen Immunity
Methodological Recommendations
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For subcellular localization studies, use Airyscan confocal microscopy to track SOBIR1 microdomains on the plasma membrane and their coordination with ER remodeling .
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In kinase activity assays, combine in vitro kinase assays (SOBIR1-KD + ATP) with in vivo phosphoproteomics to map phosphorylation sites .
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For contradictory phenotypes, employ tissue-specific CRISPR-Cas9 knockouts to bypass pleiotropic effects of constitutive sobir1 mutations .
