HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 277, Issue 23, 21017-21026, June 7, 2002

This Article Full Text Full Text (PDF) All Versions of this Article: 277/23/21017    most recent M200019200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Matsuo, H. Articles by Endou, H. Search for Related Content PubMed PubMed Citation Articles by Matsuo, H. Articles by Endou, H. Social Bookmarking                      What's this?

Identification of a Novel Na⁺-independent Acidic Amino Acid Transporter with Structural Similarity to the Member of a Heterodimeric Amino Acid Transporter Family Associated with Unknown Heavy Chains^*

Hirotaka Matsuo^§, Yoshikatsu Kanai^¶, Ju Young Kim, Arthit Chairoungdua, Do Kyung Kim, Jun Inatomi, Yasuhiro Shigeta^**, Hisako Ishimine^§, Sophapun Chaekuntode, Kittipong Tachampa, Hye Won Choi, Ellappan Babu, Jun Fukuda^§, and Hitoshi Endou

From the  Department of Pharmacology and Toxicology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611, the ^§ First Department of Physiology, National Defense Medical College, 3-2 Namiki, Tokorozawa, Saitama 359-8513, the ^** Department of Urology, Chiba University School of Medicine, 1-8-1 Inohana, Chuo-Ku, Chiba 260-8670, and ^¶ PRESTO, Japan Science and Technology Corporation, 6-20-2 Shinkawa, Mitaka, Tokyo 181-8611, Japan

We identified a novel Na⁺-independent acidic amino acid transporter designated AGT1 (aspartate/glutamate transporter 1). AGT1 exhibits the highest sequence similarity (48% identity) to the Na⁺-independent small neutral amino acid transporter Asc (asc-type amino acid transporter)-2 a member of the heterodimeric amino acid transporter family presumed to be associated with unknown heavy chains (Chairoungdua, A., Kanai, Y., Matsuo, H., Inatomi, J., Kim, D. K., and Endou, H. (2001) J. Biol. Chem. 276, 49390-49399). The cysteine residue responsible for the disulfide bond formation between transporters (light chains) and heavy chain subunits of the heterodimeric amino acid transporter family is conserved for AGT1. Because AGT1 solely expressed or coexpressed with already known heavy chain 4F2hc (4F2 heavy chain) or rBAT (related to b^0,+-amino acid transporter) did not induce functional activity, we generated fusion proteins in which AGT1 was connected with 4F2hc or rBAT. The fusion proteins were sorted to the plasma membrane and expressed the Na⁺-independent transport activity for acidic amino acids. Distinct from the Na⁺-independent cystine/glutamate transporter xCT structurally related to AGT1, AGT1 did not accept cystine, homocysteate, and L--aminoadipate and exhibited high affinity to aspartate as well as glutamate, suggesting that the negative charge recognition site in the side chain-binding site of AGT1 would be closer to the -carbon binding site compared with that of xCT. The AGT1 message was predominantly expressed in kidney. In mouse kidney, AGT1 protein was present in the basolateral membrane of the proximal straight tubules and distal convoluted tubules. In the Western blot analysis, AGT1 was detected as a high molecular mass band in the nonreducing condition, whereas the band shifted to a 40-kDa band corresponding to the AGT1 monomer in the reducing condition, suggesting the association of AGT1 with other protein via a disulfide bond. The finding of AGT1 and Asc-2 has established a new subgroup of the heterodimeric amino acid transporter family whose members associate not with 4F2hc or rBAT but with other unknown heavy chains.

The nucleotide sequence(s) reported in this paper has been submitted to the GenBank^TM/EBI Data Bank with accession number(s) AB072352.

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				S. Broer Amino Acid Transport Across Mammalian Intestinal and Renal Epithelia Physiol Rev, January 1, 2008; 88(1): 249 - 286. [Abstract] [Full Text] [PDF]

				L. Reggiani, D. Raciti, R. Airik, A. Kispert, and A. W. Brandli The prepattern transcription factor Irx3 directs nephron segment identity Genes & Dev., September 15, 2007; 21(18): 2358 - 2370. [Abstract] [Full Text] [PDF]

				E. Fernandez, D. Torrents, A. Zorzano, M. Palacin, and J. Chillaron Identification and Functional Characterization of a Novel Low Affinity Aromatic-preferring Amino Acid Transporter (arpAT): ONE OF THE FEW PROTEINS SILENCED DURING PRIMATE EVOLUTION J. Biol. Chem., May 13, 2005; 280(19): 19364 - 19372. [Abstract] [Full Text] [PDF]

				E. Babu, Y. Kanai, A. Chairoungdua, D. K. Kim, Y. Iribe, S. Tangtrongsup, P. Jutabha, Y. Li, N. Ahmed, S. Sakamoto, et al. Identification of a Novel System L Amino Acid Transporter Structurally Distinct from Heterodimeric Amino Acid Transporters J. Biol. Chem., October 31, 2003; 278(44): 43838 - 43845. [Abstract] [Full Text] [PDF]

				G. E. Mann, D. L. Yudilevich, and L. Sobrevia Regulation of Amino Acid and Glucose Transporters in Endothelial and Smooth Muscle Cells Physiol Rev, January 1, 2003; 83(1): 183 - 252. [Abstract] [Full Text] [PDF]