FRO2 interacts with IRT1 and AHA2 in root epidermal cells to form a high-affinity iron uptake complex . Co-immunoprecipitation (Co-IP) experiments confirmed:
Interaction partners:
| Protein | Role | Method |
|---|---|---|
| IRT1 | Fe²⁺ transporter | Co-IP with mCitrine |
| AHA2 | Proton-ATPase (pH regulation) | Split-Ub assay |
This complex enhances iron solubility and uptake efficiency under iron-deficient conditions .
Iron-dependent expression: FRO2 mRNA accumulates under iron starvation but requires low iron for enzymatic activity .
Tissue specificity: Expressed in root epidermal cells and anther filaments, critical for iron delivery to pollen grains .
Transgenic 35S-FRO2 plants show:
Enhanced iron uptake: Improved growth on low-iron media due to elevated Fe³⁺ reductase activity .
Copper reductase activity: FRO2 reduces Cu²⁺ to Cu⁺, though this role remains secondary to iron uptake .