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Sodium myo-inositol cotransporter transporters C

Unless otherwise stated all data on this page refer to the human proteins. Gene information is provided for human (Hs), mouse (Mm) and rat (Rn).


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Three different mammalian myo-inositol cotransporters are currently known; two are the Na+-coupled SMIT1 and SMIT2 tabulated below and the third is proton-coupled HMIT (SLC2A13). SMIT1 and SMIT2 have a widespread and overlapping tissue location but in polarized cells, such as the Madin-Darby canine kidney cell line, they segregate to the basolateral and apical membranes, respectively [2]. In the nephron, SMIT1 mediates myo-inositol uptake as a ‘compatible osmolyte’ when inner medullary tubules are exposed to increases in extracellular osmolality, whilst SMIT2 mediates the reabsorption of myo-inositol from the filtrate. In some species (e.g. rat, but not rabbit) apically located SMIT2 is responsible for the uptake of myo-inositol from the intestinal lumen [1].


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Targets of relevance to immunopharmacology are highlighted in blue

SMIT1 (SMIT / SLC5A3) C Show summary »

Target Id 924
Nomenclature SMIT
Systematic nomenclature SLC5A3
Common abbreviation SMIT1
Previous and unofficial names Sodium/myo-inositol cotransporter (SMIT) | solute carrier family 5 (inositol transporter), member 3 | solute carrier family 5 (sodium/myo-inositol cotransporter), member 3 | solute carrier family 5 (inositol transporters)
Genes SLC5A3 (Hs), Slc5a3 (Mm), Slc5a3 (Rn)
Ensembl ID ENSG00000198743 (Hs), ENSMUSG00000089774 (Mm), ENSRNOG00000067988 (Rn)
UniProtKB AC P53794 (Hs), Q9JKZ2 (Mm)
Bioparadigms SLC Tables SLC5A3 (Hs)
Substrates myo-inositol, scyllo-inositol > L-fucose > L-xylose > L-glucose, D-glucose, α-MDG > D-galactose, D-fucose > D-xylose  [5]
phlorizin [4]
Stoichiometry 2 Na+ :1 myo-inositol [5]

SMIT2 (SGLT6 / SLC5A11) C Show summary »


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How to cite this family page

Database page citation:

Sodium myo-inositol cotransporter transporters. Accessed on 21/05/2024. IUPHAR/BPS Guide to PHARMACOLOGY,

Concise Guide to PHARMACOLOGY citation:

Alexander SPH, Fabbro D, Kelly E, Mathie AA, Peters JA, Veale EL, Armstrong JF, Faccenda E, Harding SD, Davies JA et al. (2023) The Concise Guide to PHARMACOLOGY 2023/24: Transporters. Br J Pharmacol. 180 Suppl 2:S374-469.