The plasma membrane potential is mainly considered as the driving force for ion and nutrient translocation. Using the yeast Saccharomyces cerevisiae as a model organism, we have discovered a novel role of the membrane potential in the organization of the plasma membrane. Within the yeast plasma membrane, two non-overlapping sub-compartments can be visualized. The first one, represented by a net...

There are two classes of glucose transporters involved in glucose homeostasis in the body, the facilitated transporters or uniporters (GLUTs) and the active transporters or symporters (SGLTs). The energy for active glucose transport is provided by the sodium gradient across the cell membrane, the Na(+) glucose cotransport hypothesis first proposed in 1960 by Crane. Since the cloning of SGLT1 in...

Homeostasis of inorganic phosphate (P(i)) and sulphate (Si) is largely achieved by absorption in the mammalian small intestine and by reabsorption in the proximal tubule of the kidney. Under normal physiological conditions, the kidney appears to play the major role in maintaining the extracellular concentration of these anions. In both epithelia, reabsorption of P(i) and to some extent also of ...

One fundamentally important problem for understanding the mechanism of coupling between substrate and H(+) translocation with secondary active transport proteins is the identification and physical localization of residues involved in substrate and H(+) binding. This information is exceptionally difficult to obtain with the Major Facilitator Superfamily (MFS) because of the broad sequence divers...