BRI1 Antibody
Description
Introduction to BRI1 Antibody
The BRI1 antibody (AS12 1859) is a polyclonal antibody produced in rabbits using a synthetic peptide derived from the Arabidopsis thaliana BRI1 protein (Uniprot: O22476, TAIR: AT4G39400) . It is affinity-purified for high specificity and primarily used to detect BRI1 in Western blot (WB) and immunoprecipitation (IP) assays. BRI1 is a plasma membrane-localized leucine-rich repeat receptor-like kinase (LRR-RLK) critical for BR perception and signal transduction .
3.1. Protein Detection and Quantification
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Western Blot Analysis: The antibody detects BRI1 in microsomal protein extracts, confirming its expression and post-translational modifications. For example, it identified BRI1 ubiquitination in studies exploring BR-induced receptor degradation .
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Subcellular Localization: Immunoblots using this antibody demonstrated BRI1’s plasma membrane localization and its reduced endocytosis in pub12pub13 mutants .
3.2. Post-Translational Modification Studies
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Phosphorylation: The antibody helped characterize BRI1’s autophosphorylation on serine, threonine, and tyrosine residues (e.g., Tyr-831, Thr-880, Thr-1049) .
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Ubiquitination: It detected ubiquitinated BRI1 in assays examining PUB12/PUB13 E3 ligase-mediated receptor degradation .
3.3. Interaction Studies
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Co-Immunoprecipitation (Co-IP): The antibody co-precipitated BRI1 with its coreceptor BAK1 and E3 ligases like PUB13, revealing BR-induced complex formation .
4.1. BRI1 Kinase Activity
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The antibody confirmed BRI1’s role as a dual-specificity kinase through in vitro assays, showing phosphorylation on tyrosine residues (e.g., Tyr-956, Tyr-1072) in addition to serine/threonine residues .
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Mutational studies (e.g., bri1-101 kinase domain mutant) revealed reduced kinase activity, impacting BR signaling .
4.2. Regulatory Mechanisms
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Ubiquitination and Stability: BRI1 antibody-based assays showed that PUB12/PUB13 E3 ligases promote BRI1 ubiquitination, while deubiquitinating enzymes UBP12/UBP13 stabilize it .
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Ligand-Induced Changes: BL (brassinolide) treatment increased BRI1-PUB13 association and phosphorylation, as demonstrated via IP-WB workflows .
Table 1: BRI1 Phosphorylation Sites Identified Using the Antibody
Technical Considerations
Product Specs
Target Background
- Identification of 83 novel BRI1 point mutations, including nine exhibiting an allelic series of bri1 phenotypes ranging from subtle to severe morphological alterations. PMID: 28461403
- Signaling specificity between pathways may be attributed to the spatial separation of FLS2 and BRI1, along with their associated signaling components, within distinct plasma membrane nanodomains. PMID: 28262094
- PP2A regulatory B subunits mediate BRI1 binding and dephosphorylation; PP2A subcellular localization dictates substrate selection and its effects on BR signaling. PMID: 26517938
- Compromised brassinosteroid signaling in *zea mays bri1* (zmbri1) RNA interference transgenic lines, evidenced by reduced brassinolide response and altered BR marker gene expression. PMID: 26162429
- Brassinosteroid (BR) promotes BRI1 partitioning into functional membrane microdomains to activate BR signaling. PMID: 25896454
- Brassinosteroid hormone receptor BRI1 internalization and vacuolar targeting are regulated by ubiquitination. PMID: 25608221
- Complex differential regulation of BRI1 expression influences receptor distribution and abundance, modulating brassinosteroid signaling. PMID: 24488524
- Endocytosis of the leucine-rich repeat receptor kinase, brassinosteroid insensitive1 (BRI1), is AP-2 dependent. PMID: 23975899
- BRI1-mediated signaling is amenable to mathematical modeling to elucidate the spatial and temporal dynamics of signal transduction cascades in plants. PMID: 23421559
- Multiple brassinosteroid signaling kinases (BSKs) interact with and are phosphorylated by BRI1. PMID: 23496207
- BRI1 receptor occupancy is correlated with root growth. PMID: 22802611
- A missense mutation in the Arabidopsis *bri1 suppressor 3* (*ebs3*) gene suppresses the dwarf phenotype of *bri1-9*, which arises from ER retention and ERAD of BRI1. PMID: 22733738
- Development of a novel assay for recombinant BRI1 transphosphorylation activity, suggesting a potential link between Ca2+ and BR signaling. PMID: 22309147
- BRI1-GFP fluorescence lifetime imaging (FLTI) as a non-invasive probe for analyzing long-distance brassinolide signaling in Arabidopsis seedlings. PMID: 21617383
- Serine-891 autophosphorylation is a BRI1 deactivation mechanism inhibiting BR signaling *in vivo*. PMID: 22184234
- BRI1 mutation can enhance photosynthesis and leaf growth/vascularization, suggesting approaches to improve whole-plant carbon assimilation and growth. PMID: 21795582
- Quantification of BRI1-GFP fusion protein under its native promoter. PMID: 21617031
- X-ray diffraction analysis of the *Arabidopsis thaliana* BRI1 ligand-binding domain at 2.5 Å resolution. PMID: 21666665
- Crystal structures of BRI1(LRR) in free and brassinolide-bound forms. PMID: 21666666
- Identification of a new *bri1* allele, *bri1-120*, with an uncharacterized mutation site. PMID: 21219661
- Phosphorylation of a key tyrosine within a membrane-targeting motif releases BKI1 into the cytosol upon ligand perception by BRI1. PMID: 21289069
- *bri1-R1* compensates for *bri1-5*-induced protein-folding abnormalities, restoring receptor accumulation and cell surface delivery. PMID: 20457881
- *bri1-9* mutant exhibits enhanced cold resistance compared to BRI1-overexpressing transgenic plants and wild-type. PMID: 20053182
- Brassinosteroids bind directly to the 94 amino acids of ID-LRR22 in BRI1's extracellular domain, defining a novel steroid hormone binding domain. PMID: 15650741
- BRI1 is a component of the Arabidopsis SOMATIC EMBRYOGENESIS RECEPTOR-LIKE KINASE1 protein complex. PMID: 16473966
- BKI1, a negative regulator of brassinosteroid signaling, interacts with BRI1. BKI1 is a BRI1 kinase substrate, limiting BRI1 interaction with its co-receptor BAK1, thus preventing BRI1 activation. PMID: 16857903
- Attenuated brassinosteroid signaling enhances FLC expression and delays flowering. PMID: 17611230
- *bri1-301*, despite severely impaired kinase activity, retains partial function in regulating plant growth and development. PMID: 18332904
- Identification of three homologous brassinosteroid (BR)-signaling kinases (BSK1, BSK2, and BSK3), phosphorylated by BRI1 and activating downstream BR signal transduction. PMID: 18653891
