Sodium-glucose cotransporters display sodium- and phlorizin-dependent water permeability

被引:35
作者
Loike, JD
Hickman, S
Kuang, KY
Xu, M
Cao, L
Vera, JC
Silverstein, SC
Fischbarg, J
机构
[1] COLUMBIA UNIV, DEPT PHYSIOL & CELLULAR BIOPHYS, ROVER LAB, NEW YORK, NY 10032 USA
[2] COLUMBIA UNIV, DEPT OPHTHALMOL, NEW YORK, NY 10032 USA
[3] MEM SLOAN KETTERING CANC CTR, PROGRAM MOL BIOL, NEW YORK, NY 10021 USA
来源
AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY | 1996年 / 271卷 / 05期
关键词
channels; osmotic permeability; Xenopus laevis oocytes; phloretin; sodium-glucose transporter 1;
D O I
10.1152/ajpcell.1996.271.5.C1774
中图分类号
Q2 [细胞生物学];
学科分类号
071009 ; 090102 ;
摘要
Expression of Na+-glucose cotransporters of the SGLT-1 type by Xenopus laevis oocytes increased the osmotic water permeability (P-f) of oocytes by a factor of 1.9-2.8, in the presence and in the absence of 5 mM extracellular glucose. The P-f increase was correlated with the amount of SGLT-1 cRNA injected. In oocytes expressing SGLT-1, either addition of phlorizin to the medium or the replacement of Na+ by choline inhibited the uptake of methyl-alpha-D-glucopyranoside, a specific substrate for SGLT-1, and returned oocyte P-f to its level in uninjected oocytes. Phlorizin inhibited the SGLT-1-attributable increase in P-f with an inhibition constant (K-i) of 6.1 mu M, a value analogous to the K-i for phlorizin inhibition of sugar uptake. However, neither the presence of phlorizin nor the absence of extracellular Na+ significantly affected the increase in P-f elicited in oocytes expressing GLUT-1, a facilitative glucose transporter. These findings suggest that SGLT-1 forms a pore that allows the transmembrane passage of water and that water and glucose traverse the protein through this pore. The finding that removal of extracellular Na+ abolishes the increase in P-f attributable to SGLT-1 suggests that extracellular Na+ is required to maintain patency of this transporter's water-permeable transmembrane pore.
引用
收藏
页码:C1774 / C1779
页数:6
相关论文
共 33 条
[1]  
ARANT S, 1991, Biophysical Journal, V59, p333A
[2]   MOLECULAR-BIOLOGY OF MAMMALIAN GLUCOSE TRANSPORTERS [J].
BELL, GI ;
KAYANO, T ;
BUSE, JB ;
BURANT, CF ;
TAKEDA, J ;
LIN, D ;
FUKUMOTO, H ;
SEINO, S .
DIABETES CARE, 1990, 13 (03) :198-208
[3]   ACTION OF PHLORIDZIN AND SUGARS ON (NA+-K+)-ACTIVATED ATPASE [J].
BRITTEN, JS ;
BLANK, M .
JOURNAL OF MEMBRANE BIOLOGY, 1969, 1 (03) :238-&
[4]  
BURANT CF, 1992, J BIOL CHEM, V267, P14523
[5]   FACILITATED DIFFUSION OF GLUCOSE [J].
CARRUTHERS, A .
PHYSIOLOGICAL REVIEWS, 1990, 70 (04) :1135-1176
[6]   CULTURED BOVINE CORNEAL ENDOTHELIAL-CELLS EXPRESS CHIP28 WATER CHANNELS [J].
ECHEVARRIA, M ;
KUANG, KY ;
ISEROVICH, P ;
LI, J ;
PRESTON, GM ;
AGRE, P ;
FISCHBARG, J .
AMERICAN JOURNAL OF PHYSIOLOGY, 1993, 265 (05) :C1349-C1355
[7]   MULTIFUNCTIONAL TRANSPORTER MODELS - LESSONS FROM THE TRANSPORT OF WATER, SUGARS, AND RING COMPOUNDS BY GLUTS [J].
FISCHBARG, J ;
VERA, JC .
AMERICAN JOURNAL OF PHYSIOLOGY-CELL PHYSIOLOGY, 1995, 268 (05) :C1077-C1089
[8]   GLUCOSE TRANSPORTERS SERVE AS WATER CHANNELS [J].
FISCHBARG, J ;
KUANG, K ;
VERA, JC ;
ARANT, S ;
SILVERSTEIN, SC ;
LOIKE, J ;
ROSEN, OM .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 1990, 87 (08) :3244-3247
[9]  
FISCHBARG J, 1993, ALFRED BENZON SYMP S, V34, P432
[10]   FACILITATIVE GLUCOSE TRANSPORTERS - AN EXPANDING FAMILY [J].
GOULD, GW ;
BELL, GI .
TRENDS IN BIOCHEMICAL SCIENCES, 1990, 15 (01) :18-23