TY - JOUR
T1 - Human Na+-dependent vitamin C transporter 1 (hSVCT1)
T2 - Primary structure, functional characteristics and evidence for a non-functional splice variant
AU - Wang, Haiping
AU - Dutta, Binita
AU - Huang, Wei
AU - Devoe, Lawrence D
AU - Leibach, Frederick H.
AU - Ganapathy, Vadivel
AU - Prasad, Puttur D
N1 - Funding Information:
This work was supported by National Institutes of Health Grant HD 33347 to V. Ganapathy.
PY - 1999/11/9
Y1 - 1999/11/9
N2 - We report here on the cloning and functional characterization of human Na+-dependent vitamin C transporter 1 (SVCT1). The human SVCT1 cDNA, obtained from a Caco2 cell cDNA library, encodes a protein of 598 amino acids with 12 putative transmembrane domains. The SVCT1-specific transcript, 2.4 kb in size, is expressed in kidney, liver, small intestine, thymus and prostate. When expressed heterologously in HRPE cells, SVCT1 mediates the transport of ascorbate, the reduced form of vitamin C, in a Na+-dependent manner. The transporter is specific for ascorbate with a K(t) of ~75 μM. The relationship between the cDNA-specific uptake rate of ascorbate and Na+ concentration is sigmoidal with a Na+:ascorbate stoichiometry of 2:1, indicating that the transport process is electrogenic. In Caco2 cells and in normal human intestine, SVCT1 also exists as a non-functional splice variant with a four amino acid sequence inserted between E-155 and V-156. The splice variant results from the use of a donor site 12 bp downstream of the normal donor site. Copyright (C) 1999.
AB - We report here on the cloning and functional characterization of human Na+-dependent vitamin C transporter 1 (SVCT1). The human SVCT1 cDNA, obtained from a Caco2 cell cDNA library, encodes a protein of 598 amino acids with 12 putative transmembrane domains. The SVCT1-specific transcript, 2.4 kb in size, is expressed in kidney, liver, small intestine, thymus and prostate. When expressed heterologously in HRPE cells, SVCT1 mediates the transport of ascorbate, the reduced form of vitamin C, in a Na+-dependent manner. The transporter is specific for ascorbate with a K(t) of ~75 μM. The relationship between the cDNA-specific uptake rate of ascorbate and Na+ concentration is sigmoidal with a Na+:ascorbate stoichiometry of 2:1, indicating that the transport process is electrogenic. In Caco2 cells and in normal human intestine, SVCT1 also exists as a non-functional splice variant with a four amino acid sequence inserted between E-155 and V-156. The splice variant results from the use of a donor site 12 bp downstream of the normal donor site. Copyright (C) 1999.
KW - Ascorbate transport
KW - Human
KW - Intestine
KW - Na-dependent vitamin C transporter 1
KW - Na-dependent vitamin C transporter 1 splice variant
KW - Primary structure
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U2 - 10.1016/S0005-2736(99)00182-0
DO - 10.1016/S0005-2736(99)00182-0
M3 - Article
C2 - 10556483
AN - SCOPUS:0033375028
SN - 0005-2736
VL - 1461
SP - 1
EP - 9
JO - Biochimica et Biophysica Acta - Biomembranes
JF - Biochimica et Biophysica Acta - Biomembranes
IS - 1
ER -