Sodium-dependent uptake of [H-3]scyllo-inositol by Tetrahymena: Incorporation into phosphatidylinositol, phosphatidylinositol-linked glycans, and polyphosphoinositols

[H-3]Scyllo-inositol was taken up by Tetrahymena cells through a sodium-dep endent pathway wherein unlabeled scyllo- and myo-inositol competed for upta ke. D-Glucose was a competitor of [H-3]myo-inositol uptake, but did not app ear to compete for [H-3]scyllo-inositol uptake. Transport of [H-3]scyllo- a nd [H-3]myo-inositol was inhibited when sodium was removed from the labelin g buffer and by phlorizin, an inhibitor of sodium-dependent transporters. C ytochalasin B, an inhibitor of facilitated glucose transporters, had no sig nificant effect on inositol transport. Internalized [H-3]scyllo-inositol wa s readily incorporated intact into phosphatidylinositol, phosphatidylinosit ol-linked glycans, and polyphosphoinositols. Distribution of [3H]scyllo- an d [H-3]myo-inositol radioactivity into individual polyphosphoinositols was found to differ. (C) 1999 Academic Press.