Na+/myo-inositol cotransporter 2 (Na+/myo-inositol cotransporter 2, Na+/glucose cotransporter KST1, Na+-dependent glucose cotransporter, solute carrier family 5 member 11, SLC5A11, KST1, SLGTX, SMIT2)

Function

• role in the Na+-dependent cotransport of myo-inositol (MI) with a Na+:MI stoichiometry of 2:1
• exclusively responsible for apical myo-inositol transport & absorption in intestine
• also can transport D-chiro-inositol (DCI) but not L-fructose
• exhibits stereospecific cotransport of both D-glucose & D-xylose
• may induce apoptosis through the TNF-alpha, PDCD1 pathway
• may play a role in regulation of myo-inositol concentration in serum, involving reabsorption in proximal renal tubule

Structure

• belongs to the Na+:solute symporter (SSF) (TC 2.A.21) family

Compartment

membrane

Alternative splicing

named isoforms=4

Expression

• highest expression in heart, skeletal muscle, kidney, liver & placenta
• weaker expression in brain, colon, spleen, lung & peripheral blood leukocytes

Pathology

• acts as an autoimmune modifier in systemic lupus erythematosus (SLE) as it is significantly associated with low complement component 4 (C4), anti-Smith antibody, serositis, & alopecia

More general terms

• transmembrane 14e protein
• solute carrier family 5 (SLC5, SLC5A)

Database

• Kegg: http://www.genome.jp/dbget-bin/www_bget?hsa:1155
• UniProt: http://www.uniprot.org/uniprot/Q8WWX8.html