Unlocking the molecular secrets of sodium-coupled transporters

Transmembrane sodium ion gradients provide energy that can be harnessed by so-called ‘secondary transporters’ to drive the translocation of solute molecules into a cell. Decades of intense study has proven the central role that sodium-coupled transporters play in many physiological processes, making them vital targets to treat many serious diseases. Within the last year, several sodium-coupled transporter crystal structures have been reported from different families, showing a remarkable structural conservation between functionally unrelated transporters. In this review we discuss these atomic resolution structures and how they illuminate the mechanistic principles of sodium-coupled transport of solutes across cellular membranes.