Molecular and functional characterization of intestinal Na+-dependent neutral amino acid transporter B0

Ramesh Kekuda, Viviana Torres-Zamorano, You Jun Fei, Puttur D Prasad, Hui W. Li, Lisa D. Mader, Frederick H. Leibach, Vadivel Ganapathy

Research output: Contribution to journalArticle

102 Citations (Scopus)

Abstract

We have cloned the Na+-dependent neutral amino acid transporter B0 (ATB0) from rabbit jejunum and from the human intestinal cell line Caco-2. Rabbit intestinal ATB0 (riATB0) cDNA codes for a protein of 541 amino acids with 10 potential transmembrane domains. When expressed in HeLa cells, riATB0 mediates the transport of several neutral amino acids, including glutamine, in a Na+-dependent manner. Anionic amino acids, cationic amino acids, and N-methylated amino acids are excluded by riATB0. When expressed in Xenopus laevis oocytes, riATB0 increases the transport of neutral amino acids severalfold. The induced transport activity is specific for neutral amino acids, with no noticeable interaction with anionic, cationic, and N- methylated amino acids. However, riATB0 does interact with anionic amino acids at acidic pH. In oocytes expressing riATB0, the neutral amino acid threonine evokes inward currents at a holding potential of -50 mV. The amino acid-evoked current is sensitive to membrane potential. The inward current increases as the membrane potential is hyperpolarized, but the current reverses at about -30 to -40 mV. Threonine evokes outward currents if the membrane potential is depolarized beyond this value. We have also cloned the ATB0 from the human intestinal cell line Caco-2. The Caco-2 ATB0 cDNA also codes for a protein of 541 amino acids that is essentially identical to the ATB0 expressed in the human choriocarcinoma cell line JAR. Reverse transcription-polymerase chain reaction (RT-PCR) and restriction analysis of the RT-PCR products indicate that the human intestine and the human kidney proximal tubular cell line HKPT express an ATB0 identical to the ATB0 expressed in Caco-2 cells.

Original languageEnglish (US)
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume272
Issue number6 35-6
StatePublished - Jun 1 1997

Fingerprint

Neutral Amino Acid Transport Systems
Neutral Amino Acids
Rabbits
Amino Acids
Membrane Potentials
Acids
Cell Line
Threonine
Reverse Transcription
Oocytes
Complementary DNA
Acidic Amino Acids
Polymerase Chain Reaction
Choriocarcinoma
Caco-2 Cells
Xenopus laevis
Jejunum
Glutamine
HeLa Cells
Intestines

Keywords

  • Hartnup disease
  • Intestine
  • Primary structure
  • System B

ASJC Scopus subject areas

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

Cite this

Molecular and functional characterization of intestinal Na+-dependent neutral amino acid transporter B0. / Kekuda, Ramesh; Torres-Zamorano, Viviana; Fei, You Jun; Prasad, Puttur D; Li, Hui W.; Mader, Lisa D.; Leibach, Frederick H.; Ganapathy, Vadivel.

In: American Journal of Physiology - Gastrointestinal and Liver Physiology, Vol. 272, No. 6 35-6, 01.06.1997.

Research output: Contribution to journalArticle

Kekuda, Ramesh ; Torres-Zamorano, Viviana ; Fei, You Jun ; Prasad, Puttur D ; Li, Hui W. ; Mader, Lisa D. ; Leibach, Frederick H. ; Ganapathy, Vadivel. / Molecular and functional characterization of intestinal Na+-dependent neutral amino acid transporter B0. In: American Journal of Physiology - Gastrointestinal and Liver Physiology. 1997 ; Vol. 272, No. 6 35-6.
@article{2788c246e4654f1caea99d87774b8230,
title = "Molecular and functional characterization of intestinal Na+-dependent neutral amino acid transporter B0",
abstract = "We have cloned the Na+-dependent neutral amino acid transporter B0 (ATB0) from rabbit jejunum and from the human intestinal cell line Caco-2. Rabbit intestinal ATB0 (riATB0) cDNA codes for a protein of 541 amino acids with 10 potential transmembrane domains. When expressed in HeLa cells, riATB0 mediates the transport of several neutral amino acids, including glutamine, in a Na+-dependent manner. Anionic amino acids, cationic amino acids, and N-methylated amino acids are excluded by riATB0. When expressed in Xenopus laevis oocytes, riATB0 increases the transport of neutral amino acids severalfold. The induced transport activity is specific for neutral amino acids, with no noticeable interaction with anionic, cationic, and N- methylated amino acids. However, riATB0 does interact with anionic amino acids at acidic pH. In oocytes expressing riATB0, the neutral amino acid threonine evokes inward currents at a holding potential of -50 mV. The amino acid-evoked current is sensitive to membrane potential. The inward current increases as the membrane potential is hyperpolarized, but the current reverses at about -30 to -40 mV. Threonine evokes outward currents if the membrane potential is depolarized beyond this value. We have also cloned the ATB0 from the human intestinal cell line Caco-2. The Caco-2 ATB0 cDNA also codes for a protein of 541 amino acids that is essentially identical to the ATB0 expressed in the human choriocarcinoma cell line JAR. Reverse transcription-polymerase chain reaction (RT-PCR) and restriction analysis of the RT-PCR products indicate that the human intestine and the human kidney proximal tubular cell line HKPT express an ATB0 identical to the ATB0 expressed in Caco-2 cells.",
keywords = "Hartnup disease, Intestine, Primary structure, System B",
author = "Ramesh Kekuda and Viviana Torres-Zamorano and Fei, {You Jun} and Prasad, {Puttur D} and Li, {Hui W.} and Mader, {Lisa D.} and Leibach, {Frederick H.} and Vadivel Ganapathy",
year = "1997",
month = "6",
day = "1",
language = "English (US)",
volume = "272",
journal = "American journal of physiology. Gastrointestinal and liver physiology",
issn = "0193-1857",
publisher = "American Physiological Society",
number = "6 35-6",

}

TY - JOUR

T1 - Molecular and functional characterization of intestinal Na+-dependent neutral amino acid transporter B0

AU - Kekuda, Ramesh

AU - Torres-Zamorano, Viviana

AU - Fei, You Jun

AU - Prasad, Puttur D

AU - Li, Hui W.

AU - Mader, Lisa D.

AU - Leibach, Frederick H.

AU - Ganapathy, Vadivel

PY - 1997/6/1

Y1 - 1997/6/1

N2 - We have cloned the Na+-dependent neutral amino acid transporter B0 (ATB0) from rabbit jejunum and from the human intestinal cell line Caco-2. Rabbit intestinal ATB0 (riATB0) cDNA codes for a protein of 541 amino acids with 10 potential transmembrane domains. When expressed in HeLa cells, riATB0 mediates the transport of several neutral amino acids, including glutamine, in a Na+-dependent manner. Anionic amino acids, cationic amino acids, and N-methylated amino acids are excluded by riATB0. When expressed in Xenopus laevis oocytes, riATB0 increases the transport of neutral amino acids severalfold. The induced transport activity is specific for neutral amino acids, with no noticeable interaction with anionic, cationic, and N- methylated amino acids. However, riATB0 does interact with anionic amino acids at acidic pH. In oocytes expressing riATB0, the neutral amino acid threonine evokes inward currents at a holding potential of -50 mV. The amino acid-evoked current is sensitive to membrane potential. The inward current increases as the membrane potential is hyperpolarized, but the current reverses at about -30 to -40 mV. Threonine evokes outward currents if the membrane potential is depolarized beyond this value. We have also cloned the ATB0 from the human intestinal cell line Caco-2. The Caco-2 ATB0 cDNA also codes for a protein of 541 amino acids that is essentially identical to the ATB0 expressed in the human choriocarcinoma cell line JAR. Reverse transcription-polymerase chain reaction (RT-PCR) and restriction analysis of the RT-PCR products indicate that the human intestine and the human kidney proximal tubular cell line HKPT express an ATB0 identical to the ATB0 expressed in Caco-2 cells.

AB - We have cloned the Na+-dependent neutral amino acid transporter B0 (ATB0) from rabbit jejunum and from the human intestinal cell line Caco-2. Rabbit intestinal ATB0 (riATB0) cDNA codes for a protein of 541 amino acids with 10 potential transmembrane domains. When expressed in HeLa cells, riATB0 mediates the transport of several neutral amino acids, including glutamine, in a Na+-dependent manner. Anionic amino acids, cationic amino acids, and N-methylated amino acids are excluded by riATB0. When expressed in Xenopus laevis oocytes, riATB0 increases the transport of neutral amino acids severalfold. The induced transport activity is specific for neutral amino acids, with no noticeable interaction with anionic, cationic, and N- methylated amino acids. However, riATB0 does interact with anionic amino acids at acidic pH. In oocytes expressing riATB0, the neutral amino acid threonine evokes inward currents at a holding potential of -50 mV. The amino acid-evoked current is sensitive to membrane potential. The inward current increases as the membrane potential is hyperpolarized, but the current reverses at about -30 to -40 mV. Threonine evokes outward currents if the membrane potential is depolarized beyond this value. We have also cloned the ATB0 from the human intestinal cell line Caco-2. The Caco-2 ATB0 cDNA also codes for a protein of 541 amino acids that is essentially identical to the ATB0 expressed in the human choriocarcinoma cell line JAR. Reverse transcription-polymerase chain reaction (RT-PCR) and restriction analysis of the RT-PCR products indicate that the human intestine and the human kidney proximal tubular cell line HKPT express an ATB0 identical to the ATB0 expressed in Caco-2 cells.

KW - Hartnup disease

KW - Intestine

KW - Primary structure

KW - System B

UR - http://www.scopus.com/inward/record.url?scp=0030761681&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0030761681&partnerID=8YFLogxK

M3 - Article

C2 - 9227483

AN - SCOPUS:0030761681

VL - 272

JO - American journal of physiology. Gastrointestinal and liver physiology

JF - American journal of physiology. Gastrointestinal and liver physiology

SN - 0193-1857

IS - 6 35-6

ER -