How to switch affinity

摘要

To acquire nutrients from their surroundings, cells produce proteins that act as transporters, channels and pumps, creating passages in the plasma membrane through which molecules can pass. Unlike channels, pumps and transporters must undergo conformational changes to transfer substrates across the membrane. In plants, the transporter NRT1.1 (also known as CHL1 or NPF6.3) is essential for cellular uptake of nitrate. Unusually for a transporter, NRT1.1 regulates ion uptake by changing its affinity for nitrate ions depending on the availability of nitrate in the soil. However, the structural basis of this behaviour is not understood. Two articles in this issue provide possible answers, by finally determining structures of NRT1.1 two decades after its identification.