Click here to close
Hello! We notice that you are using Internet Explorer, which is not supported by Xenbase and may cause the site to display incorrectly.
We suggest using a current version of Chrome,
FireFox, or Safari.
J Physiol
2004 Aug 01;558Pt 3:759-68. doi: 10.1113/jphysiol.2004.064311.
Show Gene links
Show Anatomy links
Expression of the sodium-myo-inositol cotransporter SMIT2 at the apical membrane of Madin-Darby canine kidney cells.
Bissonnette P
,
Coady MJ
,
Lapointe JY
.
???displayArticle.abstract???
Myo-inositol is a compatible osmolyte used by cells which are challenged by variations in extracellular osmolarity, as in the renal medulla. In order to accumulate large quantities of this polyol, cells rely on Na(+)-dependent transporters such as SMIT1. We have recently identified a second Na(+)-myo-inositol cotransporter, SMIT2, which presents transport characteristics corresponding to those recently described for the apical membrane of renal proximal tubules. In order to further characterize this transport system, we transfected Madin-Darby canine kidney (MDCK) cells with rabbit SMIT2 cDNA and selected a stable clone with a high expression level. The accumulation of radiolabelled myo-inositol by this cell line is 20-fold larger than that seen in native MDCK cells. The affinity for myo-inositol of MDCK cells transfected with SMIT2 is slightly lower (K(m)= 334 microm) than that found in voltage-clamped Xenopus laevis oocytes expressing SMIT2 (K(m)= 120 microm). Transport studies performed using semipermeable filters showed complete apical targeting of the SMIT2 transporter. This apical localization of SMIT2 was confirmed by transport studies on purified rabbit renal brush border membrane vesicles (BBMVs). Using a purified antibody against SMIT2, we were also able to detect the SMIT2 protein (molecular mass = 66 kDa) in Western blots of BBMVs purified from SMIT2-transfected MDCK cells. SMIT2 activity was also shown to be stimulated 5-fold when submitted to 24 h hypertonic treatment (+200 mosmol l(-1)). The SMIT2-MDCK cell line thus appears to be a promising model for studying SMIT2 biochemistry and regulation.
Barker,
Phosphorylated inositol compounds in beta -cell stimulus-response coupling.
2002,
Pubmed
Berry,
The effect of glucose and galactose toxicity on myo-inositol transport and metabolism in human skin fibroblasts in culture.
1994,
Pubmed
Bissonnette,
Kinetic separation and characterization of three sugar transport modes in Caco-2 cells.
1996,
Pubmed
,
Xenbase
Bissonnette,
Functional expression of tagged human Na+-glucose cotransporter in Xenopus laevis oocytes.
1999,
Pubmed
,
Xenbase
Burg,
Regulation of gene expression by hypertonicity.
1997,
Pubmed
Coady,
Identification of a novel Na+/myo-inositol cotransporter.
2002,
Pubmed
,
Xenbase
Dolhofer,
Enzymatic assay of myo-inositol in serum.
1987,
Pubmed
Einat,
The effects of inositol treatment in animal models of psychiatric disorders.
2001,
Pubmed
Eladari,
pH dependence of Na+/myo-inositol cotransporters in rat thick limb cells.
2002,
Pubmed
Grunewald,
Polarized function of thick ascending limbs of Henle cells in osmoregulation.
2001,
Pubmed
Hager,
Kinetics and specificity of the renal Na+/myo-inositol cotransporter expressed in Xenopus oocytes.
1995,
Pubmed
,
Xenbase
Hammerman,
myo-Inositol transport in renal brush border vesicles and it inhibition by D-glucose.
1980,
Pubmed
Hitomi,
cDNA sequence for rkST1, a novel member of the sodium ion-dependent glucose cotransporter family.
1994,
Pubmed
Karihaloo,
Protein kinase and Ca2+ modulation of myo-inositol transport in cultured retinal pigment epithelial cells.
1997,
Pubmed
Kitamura,
Effects of inhibition of myo-inositol transport on MDCK cells under hypertonic environment.
1997,
Pubmed
Klein,
A method for quantification and correction of proteins after transfer to immobilization membranes.
1995,
Pubmed
Kwon,
Cloning of the cDNa for a Na+/myo-inositol cotransporter, a hypertonicity stress protein.
1992,
Pubmed
,
Xenbase
Larner,
D-chiro-inositol in insulin action and insulin resistance-old-fashioned biochemistry still at work.
2001,
Pubmed
Mato,
Partial structure of an insulin-sensitive glycophospholipid.
1987,
Pubmed
Nestler,
Ovulatory and metabolic effects of D-chiro-inositol in the polycystic ovary syndrome.
1999,
Pubmed
Ostlund,
A stereospecific myo-inositol/D-chiro-inositol transporter in HepG2 liver cells. Identification with D-chiro-[3-3H]inositol.
1996,
Pubmed
Roll,
New human sodium/glucose cotransporter gene (KST1): identification, characterization, and mutation analysis in ICCA (infantile convulsions and choreoathetosis) and BFIC (benign familial infantile convulsions) families.
2002,
Pubmed
Schmolke,
Polyol determination along the rat nephron.
1990,
Pubmed
Silbernagl,
Tubular reabsorption of myo-inositol vs. that of D-glucose in rat kidney in vivo et situ.
2003,
Pubmed
Strange,
Osmoregulatory changes in myo-inositol content and Na+/myo-inositol cotransport in rat cortical astrocytes.
1994,
Pubmed
Takenawa,
myo-Inositol binding and transport in brush border membranes of rat kidney.
1977,
Pubmed
Thompson,
The CLUSTAL_X windows interface: flexible strategies for multiple sequence alignment aided by quality analysis tools.
1997,
Pubmed
Wiese,
Osmotic regulation of Na-myo-inositol cotransporter mRNA level and activity in endothelial and neural cells.
1996,
Pubmed
Winne,
Unstirred layer, source of biased Michaelis constant in membrane transport.
1973,
Pubmed
Yamauchi,
Myo-inositol and betaine transporters regulated by tonicity are basolateral in MDCK cells.
1991,
Pubmed
Yorek,
Wortmannin and LY294002 inhibit myo-inositol accumulation by cultured bovine aorta endothelial cells and murine 3T3-L1 adipocytes.
2000,
Pubmed
van Calker,
The high affinity inositol transport system--implications for the pathophysiology and treatment of bipolar disorder.
2000,
Pubmed
