Amino acid sequence and the cellular location of the Na+-dependent <scp>d</scp>-glucose symporters (SGLT1) in the ovine enterocyte and the parotid acinar cell

Tarpey, Patrick; Wood, I. Stuart; Shirazi-Beechey, Soraya P.; Beechey, R. B.

doi:10.1042/bj3120293

Cited by 40 publications

(37 citation statements)

References 29 publications

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“…The presence of multiple transcripts for SGLT1 is usual, with many species having more than one and some ruminant species having up to 5 (Wood et al 2000). This difference in size appears to be due to variation in the length of the 3' untranslated region (Peng and Lever 1995;Tarpey et al 1995;Wood et al 2000). The results of these studies indicate collectively that SGLT1 is expressed in the equine small intestine and that SGLT1 expression is highest in the proximal intestine and decreases distally.…”

Section: Northern Blot Analysis Of Sglt1 Mrna In Equine Intestinesupporting

confidence: 50%

“…We have shown that glucose and galactose are transported in the equine intestine by a Na + /glucose cotransporter isoform 1 (SGLT1). cDNA encoding SGLT1 has been cloned from the intestinal tissue of various species (Hediger et al 1987;Hediger and Rhoads 1994;Shirazi-Beechey 1995;Tarpey et al 1995;Turk and Wright 1997) and the amino acid sequences have been deduced. The comparison of SGLT1 sequences in various species indicates that this protein is conserved throughout evolution ( Wright 1993;Shirazi-Beechey 1996).…”

Section: Discussionmentioning

confidence: 99%

“…Protein concentration was determined by its ability to bind Coomassie Blue, according to the Bio-Rad assay technique (Tarpey et al 1995). Bovine γ-globulin (1-100 µg protein) was used as the standard.…”

Section: Estimation Of Proteinmentioning

confidence: 99%

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Molecular characterisation of carbohydrate digestion and absorption in equine small intestine

Dyer

Merediz

Salmon

et al. 2002

Equine Veterinary Journal

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SummaryD i e t a ry carbohydrates, when digested and absorbed in the small intestine of the horse, provide a substantial fraction of metabolisable energy. However, if levels in diets exceed the capacity of the equine small intestine to digest and absorb them, they reach the hindgut, cause alterations in micro b i a l populations and the metabolite products and predispose the horse to gastrointestinal diseases. We set out to determine, at the m o l e c u l a r level, the mechanisms, pro p e rt i e s and the site of e x p ression of carbohydrate digestive and absorptive functions of the equine small intestinal brush-border membrane. We have demonstrated that the disaccharidases sucrase, lactase and maltase are expressed diversely along the length of the intestine and D-glucose is transported across the equine intestinal brushb o r d e r membrane by a high aff i n i t y, low capacity, Na + / g l u c o s e c o t r a n s p o rt e r type 1 isoform (SGLT1). The highest rate of t r a n s p o rt is in duodenum > jejunum > ileum. We have cloned and sequenced the cDNA encoding equine SGLT1 and alignment with SGLT1 of other species indicates 85-89% homology at the nucleotide and 84-87% identity at the amino acid levels. We have shown that there is a good corre l a t i o n between levels of functional SGLT1 protein and SGLT1 mRNA abundance along the length of the small intestine. This indicates that the major site of glucose absorption in horses maintained on conventional grass-based diets is in the proximal intestine, and the expression of equine intestinal SGLT1 along the p roximal to distal axis of the intestine is regulated at the level of m R N A abundance. The data presented in this paper a re the first to provide information on the capacity of the equine intestine to digest and absorb soluble carbohydrates and has implications for a better feed management, pharmaceutical intervention and for d i e t a ry supplementation in horses following intestinal re s e c t i o n .

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Section: Northern Blot Analysis Of Sglt1 Mrna In Equine Intestinesupporting

confidence: 50%

Section: Discussionmentioning

confidence: 99%

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Molecular characterisation of carbohydrate digestion and absorption in equine small intestine

Dyer

Merediz

Salmon

et al. 2002

Equine Veterinary Journal

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“…There are many examples of membrane proteins that are basolateral in one cell type and apical in another (RodriguezBoulan & Powell, 1992;Scheiffele et al 1995). For example, the sodium ª_glucose cotransporter, which is located on the lumenal membrane of intestinal epithelial cells, resides on the basolateral domain of the parotid acinar cells (Tarpey et al 1995). It is proposed that the modulation of protein sorting could simply be brought about by inhibition of the cytoplasmic signal by post-translational modifications, which would allow the promiscuous lumenal signal to come into play and redirect the protein to the apical domain (Scheiffele et al 1995).…”

Section: Discussionmentioning

confidence: 99%

Identification and characterization of a monocarboxylate transporter (MCT1) in pig and human colon: its potential to transport l‐lactate as well as butyrate

Ritzhaupt

Wood

Ellis

et al. 1998

The Journal of Physiology

208

170

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Oligonucleotide primers based on the human heart monocarboxylate transporter (MCT1) cDNA sequence were used to isolate a 544 bp cDNA product from human colonic RNA by reverse transcription‐polymerase chain reaction (RT‐PCR). The sequence of the RT‐PCR product was identical to that of human heart MCT1. Northern blot analysis using the RT‐PCR product indicated the presence of a single transcript of 3.3 kb in mRNA isolated from both human and pig colonic tissues. Western blot analysis using an antibody to human MCT1 identified a specific protein with an apparent molecular mass of 40 kDa in purified and well‐characterized human and pig colonic lumenal membrane vesicles (LMV). Properties of the colonic lumenal membrane l‐lactate transporter were studied by the uptake of L‐[U‐14C]lactate into human and pig colonic LMV. l‐lactate uptake was stimulated in the presence of an outward‐directed anion gradient at an extravesicular pH of 5.5. Transport of l‐lactate into anion‐loaded colonic LMV appeared to be via a proton‐activated, anion exchange mechanism. l‐lactate uptake was inhibited by pyruvate, butyrate, propionate and acetate, but not by Cl− and SO42−. The uptake of l‐lactate was inhibited by phloretin, mercurials and α‐cyano‐4‐hydroxycinnamic acid (4‐CHC), but not by the stilbene anion exchange inhibitors, 4,4′‐diisothiocyanostilbene‐2,2′‐disulphonic acid (DIDS) and 4‐acetamido‐4′‐isothiocyanostilbene‐2,2′‐disulphonic acid (SITS). The results indicate the presence of a MCT1 protein on the lumenal membrane of the colon that is involved in the transport of l‐lactate as well as butyrate across the colonic lumenal membrane. Western blot analysis showed that the abundance of this protein decreases in lumenal membrane fractions isolated from colonic carcinomas compared with that detected in the normal healthy colonic tissue.

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“…The supernatant was centrifuged at 30 000 g for 30 min and the resultant pellet was resuspended in a buffer containing 300 mM mannitol, 20 mM HEPES/Tris, pH 7.4, 0.02% NaN 3 , and made homogeneous with a Hamilton syringe. The protein concentration of membranes was determined by its ability to bind Coomassie blue according to the Bio-Rad assay technique (Tarpey et al, 1995).…”

Section: Preparation Of Post-nuclear Membrane Fractions From Colonic mentioning

confidence: 99%

Molecular changes in the expression of human colonic nutrient transporters during the transition from normality to malignancy

et al. 2002

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Healthy colonocytes derive 60 -70% of their energy supply from short-chain fatty acids, particularly butyrate. Butyrate has profound effects on differentiation, proliferation and apoptosis of colonic epithelial cells by regulating expression of various genes associated with these processes. We have previously shown that butyrate is transported across the luminal membrane of the colonic epithelium via a monocarboxylate transporter, MCT1. In this paper, using immunohistochemistry and in situ hybridisation histochemistry, we have determined the profile of MCT1 protein and mRNA expression along the crypt to surface axis of healthy human colonic tissue. There is a gradient of MCT1 protein expression in the apical membrane of the cells along the crypt-surface axis rising to a peak in the surface epithelial cells. MCT1 mRNA is expressed along the cryptsurface axis and is most abundant in cells lining the crypt. Analysis of healthy colonic tissues and carcinomas using immunohistochemistry and Western blotting revealed a significant decline in the expression of MCT1 protein during transition from normality to malignancy. This was reflected in a corresponding reduction in MCT1 mRNA expression, as measured by Northern analysis. Carcinoma samples displaying reduced levels of MCT1 were found to express the high affinity glucose transporter, GLUT1, suggesting that there is a switch from butyrate to glucose as an energy source in colonic epithelia during transition to malignancy. The expression levels of MCT1 in association with GLUT1 could potentially be used as determinants of the malignant state of colonic tissue.

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Amino acid sequence and the cellular location of the Na+-dependent d-glucose symporters (SGLT1) in the ovine enterocyte and the parotid acinar cell

Cited by 40 publications

References 29 publications

Molecular characterisation of carbohydrate digestion and absorption in equine small intestine

Molecular characterisation of carbohydrate digestion and absorption in equine small intestine

Identification and characterization of a monocarboxylate transporter (MCT1) in pig and human colon: its potential to transport l‐lactate as well as butyrate

Molecular changes in the expression of human colonic nutrient transporters during the transition from normality to malignancy

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