Involved in the sodium-dependent cotransport of myo-inositol (MI) with a Na(+):MI stoichiometry of 2:1. Exclusively responsible for apical MI transport and absorption in intestine. Can also transport D-chiro-inositol (DCI) but not L-fructose. Exhibits stereospecific cotransport of both D-glucose and D-xylose. May induce apoptosis through the TNF-alpha, PDCD1 pathway. May play a role in the regulation of MI concentration in serum, involving reabsorption in at least the proximal tubule of the kidney. MI transport activity stimulated five-fold under 24 hour hypertonic shock conditions. MI inward currents were gradually inhibited as increasing amounts of phlorizin were added to the superfusion medium. When sodium is replaced by potassium, MI uptake is dramatically reduced and in the presence of L-fucose or D-chiro-inositol (DCI), the specific accumulation of tracer amounts of MI is also reduced. Located on membrane of kidney brush border membrane vesicles (BBMVs) and apical membrane of proximal convoluted tubules. Expressed in brain, lung and kidney. In the kidney, strongly expressed in the cortex, at the luminal side of proximal convoluted tubules and in BBMVs. Weaker expression observed in the medulla (at protein level). Belongs to the sodium:solute symporter (SSF) (TC 2.A.21) family.