InterPro domain: IPR016605

This group represents a high affinity nitrate transporter component from plants. It includes high-affinity nitrate transporter 3.1 (NRT3.1 or NAR2.1) from Arabidopsis, which acts as a dual component transporter with NTR2 [ 1 , 2 ]. The functional unit for high-affinity nitrate influx may be a tetramer consisting of two subunits each of NRT2.1 and NRT3.1 [ 3 ]. NRT3.1 may be involved in targeting NRT2 proteins to the plasma membrane [ 4 ]. Both NRT2.1 and NRT3.1 are coordinately down-regulated by high external nitrate [ 5 ].

1. High-affinity nitrate transport in roots of Arabidopsis depends on expression of the NAR2-like gene AtNRT3.1. Plant Physiol. 140, 1036-46
2. Characterization of a two-component high-affinity nitrate uptake system in Arabidopsis. Physiology and protein-protein interaction. Plant Physiol. 142, 1304-17
3. Characterization of an intact two-component high-affinity nitrate transporter from Arabidopsis roots. Plant J. 63, 739-48
4. Nitrate signaling and the two component high affinity uptake system in Arabidopsis. Plant Signal Behav 2, 260-2
5. Regulation of the high-affinity NO3- uptake system by NRT1.1-mediated NO3- demand signaling in Arabidopsis. Plant Physiol. 142, 1075-86