QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) Data Supplement All Versions of this Article: mol.106.032938v1 71/6/1487    most recent Submit a response Alert me when this article is cited Alert me when eLetters are posted Alert me if a correction is posted Services 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 Asaka, J.-i. Articles by Inui, K.-i. Search for Related Content PubMed PubMed Citation Articles by Asaka, J.-i. Articles by Inui, K.-i.

Identification of Essential Histidine and Cysteine Residues of the H⁺/Organic Cation Antiporter Multidrug and Toxin Extrusion (MATE)

Department of Pharmacy, Kyoto University Hospital, Faculty of Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan

Multidrug and toxin extrusion 1 (MATE1) has been isolated as an H⁺/organic cation antiporter located at the renal brush-border membranes. Previous studies using rat renal brush-border membrane vesicles indicated that cysteine and histidine residues played critical roles in H⁺/organic cation antiport activity. In the present study, essential histidine and cysteine residues of MATE1 family were elucidated. When 7 histidine and 12 cysteine residues of rat (r)MATE1 conserved among species were mutated, substitution of His-385, Cys-62, and Cys-126 led to a significant loss of tetraethylammonium (TEA) transport activity. Cell surface biotinylation and immunofluorescence analyses with confocal microscopy indicated that rMATE1 mutant proteins were localized at plasma membranes. Mutation of the corresponding residues in human (h)MATE1 and hMATE2-K also diminished the transport activity. The transport of TEA via rMATE1 was inhibited by the sulfhydryl reagent p-chloromercuribenzenesulfonate (PCMBS) and the histidine residue modifier diethyl pyrocarbonate (DEPC) in a concentration-dependent manner. The PCMBS-caused inhibition of the transport via rMATE1 was protected by an excess of various organic cations such as TEA, suggesting that cysteine residues act as substrate-binding sites. In the case of DEPC, no such protective effects were observed. These results suggest that histidine and cysteine residues are required for MATE1 to function and that cysteine residues may serve as substrate-recognition sites.

Address correspondence to: Dr. Professor Ken-ichi Inui, Department of Pharmacy, Kyoto University Hospital, Sakyo-ku, Kyoto 606-8507, Japan. E-mail: inui{at}kuhp.kyoto-u.ac.jp

This article has been cited by other articles:

				T. Matsumoto, T. Kanamoto, M. Otsuka, H. Omote, and Y. Moriyama Role of glutamate residues in substrate recognition by human MATE1 polyspecific H+/organic cation exporter Am J Physiol Cell Physiol, April 1, 2008; 294(4): C1074 - C1078. [Abstract] [Full Text] [PDF]