PHYA Antibody
Description
Introduction to PHYA Antibody
PHYA Antibody refers to antibodies specifically targeting phytochrome A (PHYA), a photoreceptor protein critical for mediating plant responses to light. PHYA is a light-labile type I phytochrome predominantly involved in far-red (FR) and red (R) light signaling, regulating processes such as de-etiolation, flowering, and photomorphogenesis . Antibodies against PHYA are widely used to study its expression, localization, and post-translational modifications in plant systems, particularly in Arabidopsis thaliana .
Immunogen and Reactivity
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Immunogen: Synthetic peptides or recombinant proteins derived from conserved regions of PHYA. For example, the Agrisera antibody (AS07 220) uses a KLH-conjugated peptide from Arabidopsis PHYA (UniProt: P14712) .
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Cross-reactivity: Validated in Arabidopsis thaliana, tobacco, and peanut . Other variants, such as the Cepham Life Sciences antibody (P34752), target phytase A (PHYA) from Aspergillus niger .
Conformational Sensitivity
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PHYA exists in two interconvertible forms: the R light–absorbing Pr form and the FR light–absorbing Pfr form. Monoclonal antibodies like mAP20 and mAR07 show preferential binding to Pr and Pfr conformations, respectively .
Light-Dependent Phosphorylation and Degradation
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PHYA mediates rapid R light–induced phosphorylation of downstream signaling components like FAR-RED ELONGATED HYPOCOTYL1 (FHY1) and FHY1-LIKE (FHL), which regulate PHYA nuclear accumulation .
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Phosphorylation of FHY1 is R/FR reversible and dependent on PHYA activity .
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Ubiquitylation of PHYA at lysine residues (K65, K92, K143, K206, K603, K942) facilitates its proteasomal degradation under light conditions .
Hinge Region Mutations and Functional Impacts
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Mutations in the hinge region (e.g., S590A, T593A, S602A) disrupt PHYA phosphorylation, reducing its ability to interact with COP1-SPA complexes and impairing photomorphogenesis .
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Phosphorylated PHYA forms are critical for FR light responses; mutants lacking phosphorylation (e.g., phyA-105, phyA-300D) exhibit defective light signaling .
Interaction with Signaling Partners
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PHYA directly binds FHY1/FHL via its Pfr form, promoting their nuclear translocation .
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PHYA inhibits COP1–SPA1 interactions in a light-dependent manner, modulating HY5 protein levels and photomorphogenesis .
Applications of PHYA Antibodies
Product Specs
Constituents: 50% Glycerol, 0.01M PBS, pH 7.4
Target Background
Phytochrome A (phyA) is a regulatory photoreceptor existing in two forms: the Pr form absorbing maximally in the red region of the spectrum and the Pfr form absorbing maximally in the far-red region. The photoconversion of Pr to Pfr triggers various morphogenetic responses, while the reconversion of Pfr to Pr cancels these responses. Pfr controls the expression of numerous nuclear genes, including those encoding the small subunit of ribulose-bisphosphate carboxylase, chlorophyll A/B binding protein, protochlorophyllide reductase, rRNA, etc. It also negatively regulates its own gene expression. PhyA plays a role in regulating flowering time. In red light conditions, phyA can phosphorylate FHY1 and possibly FHL, inactivating their co-shuttling to the nucleus. PhyA regulates phototropic responses both in the nucleus (e.g., hypocotyl elongation and cotyledon opening under high-irradiance conditions and seed germination under very-low-fluence conditions) and in the cytoplasm (e.g., negative gravitropism in blue light and red-enhanced phototropism).
- phyA modulates the abundance and activity of key regulatory transcription factors in a tissue-autonomous fashion. PMID: 27027866
- Research suggests that lysine 206 is the primary site for rapid ubiquitination and protein degradation of Arabidopsis phytochrome A. PMID: 26314334
- Phytochrome-mediated degradation of PIF1 prevents excessive activation of photomorphogenesis. PMID: 25009301
- PHYA, but not PHYB, is crucial for fine-tuning the chlorophyll biosynthetic pathway in response to partial shading. PMID: 24604733
- Nuclear FHY1 can function independently of phyA or in association with phyA to activate the expression of distinct target genes. PMID: 25071219
- phytochrome A plays a significant role in Arabidopsis seed germination. PMID: 23292879
- Distinct structural modules, each contributing different properties to phyA, are assembled on the phyA molecule. PMID: 22843485
- A hypothesis proposes that the identified amino acid substitution leads to structural changes manifested as altered signaling and phenotype displayed by the phyA-5 mutant (which exhibits reduced binding affinity to FHY1/FHL). PMID: 22516823
- phyA controls the stability of cry2. PMID: 22739826
- The truncated PHYA406 proteins inactivate COP1 in the nuclei in a light-independent manner. PMID: 22498774
- Nuclear phyA accelerates phototropism. In the fhy1 fhl mutant, where phyA remains in the cytosol, phototropic bending is slower than in the wild type. PMID: 22374392
- The PHYA amino-terminal extension domain plays a role in regulating the nuclear import of PHYA. PMID: 21969386
- Hypomethylation at a specific CG site in exon 1 is consistently associated with the release of phyA' epiallele silencing. PMID: 22466452
- A role for mesophyll-specific phyA in blue-light-dependent regulation of anthocyanin levels and novel roles for individual phy isoforms in the regulation of anthocyanin accumulation under red illumination are reported. PMID: 21455024
- Research unravels the mechanism underlying the shift of the phyA action peak from red to far-red light, showing that it relies on specific molecular interactions rather than intrinsic changes to phyA's spectral properties. PMID: 21884939
- The dracula 1 (dra1) mutant, which showed no avoidance of shade for the PHYB::LUC response, resulted from a mutation in the PHYA gene. PMID: 21398429
- Reversible activation and repression of phyA expression by darkness and light, respectively, are accompanied by reversible changes in H3 and H4 modifications of the phyA locus. PMID: 21317377
- The phyA N-terminal fragment is imported into the nucleus in a light-dependent manner. Deletion of the C-terminal domain of phyA compromises light-induced degradation of phyA in a compartmentalization-independent fashion. PMID: 21169346
- phyA without a nuclear localization or export signal sequence is localized exclusively in the cytoplasm in darkness. Rapid nuclear entry is observed after exposure to both red and far-red light. PMID: 20739301
- phyA regulates wound- and jasmonic acid-mediated JAZ1 degradation. PMID: 20435902
- Data indicate that phyA degradation is significantly slower in the cytoplasm than in the nucleus. PMID: 20473552
- Results suggest that the autophosphorylation of phyA plays a critical role in regulating plant phytochrome signaling through the control of phyA protein stability. PMID: 20203237
- Genetic variations in the PhyA locus of A. thaliana inbred strains and their effects on seedling growth under infrared light are reported. PMID: 15908601
- The potential to manipulate light signal-transduction pathways to minimize lodging problems in basmati/aromatic rice and enhance grain productivity is described. PMID: 16136335
- Data suggest that phyA, the 26S proteasome, and the Constitutive Photomorphogenic/De-Etiolated/Fusca proteins are all involved in the light regulation of FHY1 protein abundance during Arabidopsis (Arabidopsis thaliana) seedling development. PMID: 16244150
- PHYC was the most strongly associated locus across 163 strains, suggesting that PHYC alleles are under diversifying selection in A. thaliana. PMID: 16732287
- This study demonstrated that phyA plays a quantitatively dominant role in Rc-induced expression of early response genes in A. thaliana seedlings. PMID: 17076805
- The serine-rich region is involved in the negative regulation of phyA signaling. PMID: 17160561
- Data suggest that phyA may contribute significantly to the regulation of growth and development in daylight-grown plants. PMID: 17346261
- Data showed a transcriptionally suppressed epi-allele of phytochrome A gene (PHYA) methylated only in symmetric CG sites resident in exonic regions, resulting in elongated hypocotyls in seedlings grown under continuous far-red light. PMID: 17931351
- phyA is required for the up-regulation of PEX11b in the light. PMID: 18203870
- The expression levels of polyamine biosynthesis-related genes were transcribed less in the wild type than in phyA seedlings under both light conditions. PMID: 18375607
- Data show that phyA plays a dominant role in regulating the degradation of PIF1 following initial light exposure, and PIF1 interacts with phyA through a novel active phyA binding motif. PMID: 18539749
- FHY1 and FHL function as adaptor proteins facilitating nuclear transport of phyA. PMID: 18670649
- Phytochrome A mediates the localization of phot1 in Arabidopsis. PMID: 18952772
- The G-protein may be involved in the phyA signaling pathway to regulate far-red irradiation-preconditioned cell death of Arabidopsis hypocotyls. PMID: 19160542
- Phytochrome A is required for the phosphorylation of FHY1. PMID: 19208901
- A missense mutation in the PHYA histidine kinase-related domain alters the spectral sensitivity and the persistence of far-red light-induced high-irradiance responses. PMID: 19403732
Q&A
Here’s a structured FAQ for PHYA (Phytochrome A) antibodies tailored to academic research scenarios, incorporating methodological rigor and scientific depth:
Advanced Research Questions
How do I resolve contradictions in PHYA nuclear vs. cytoplasmic localization data?
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Integrated methodology:
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Perform subcellular fractionation followed by Western blotting to isolate nuclear/cytoplasmic compartments .
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Use confocal microscopy with organelle-specific markers (e.g., DAPI for nuclei, ER-Tracker for cytoplasm) .
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Analyze phosphorylation status: PHYA nuclear translocation is often phosphorylation-dependent .
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What strategies improve PHYA antibody cross-reactivity in non-model plant species?
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Computational and experimental:
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Perform epitope mapping (e.g., phage display) to identify conserved regions across species .
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Use chimeric antibodies with species-matched Fc domains to enhance compatibility (e.g., Arabidopsis PHYA antibody reformatted for rice) .
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Validate via homology modeling (e.g., SWISS-MODEL) to predict antibody-antigen docking .
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How can I assess PHYA conformational changes during photoconversion?
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Biophysical approaches:
Table 1: Promoter Selection for PHYA Transgenic Studies
| Promoter Type | Use Case | Example | Trade-offs |
|---|---|---|---|
| Constitutive (35S) | Overexpression studies | CaMV 35S | May cause pleiotropic effects |
| Inducible (GR/LhG4) | Temporal PHYA activation | Glucocorticoid | Requires dexamethasone application |
| Tissue-specific (Lhcb) | Leaf-specific knockdown | Lhcb1*1 | Limited to photosynthetic tissues |
Table 2: Antibody Validation Techniques
| Technique | Purpose | Sensitivity | Throughput |
|---|---|---|---|
| Western blot | Size confirmation | 1–10 ng | Low |
| ELISA | Quantification | 0.1–1 ng | High |
| Immunoprecipitation | Protein interaction validation | 10–100 ng | Medium |
Data Contradiction Analysis Framework
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Scenario: Discrepancies in PHYA-mediated flowering time results.
