cDNA cloning and functional characterization of rat intestinal monocarboxylate transporter.
A cDNA clone which encodes a monocarboxylate transporter (ratMCT1) was isolated from a rat small intestinal cDNA library, which was screened by using full-length MCT1 cDNA of Chinese hamster ovary cells. The ratMCT1 cDNA was sequenced and predicted a protein of 494 amino acids with twelve potential transmembrane domains. The amino acid sequence showed 93.1% and 84.6% identity to the hamster and human monocarboxylate transporters, respectively. When expressed in Xenopus laevis oocytes, the ratMCT1 cRNA caused a significant increase in the uptake of radiolabeled lactic acid. Poly(A)+ RNA transcripts hybridizing to the ratMCT1 cDNA were detected in rat brain, heart, kidney, lung, muscle and brain capillaries. These results indicate that MCT1 contributes to pH-dependent and carrier-mediated transport of monocarboxylic acids in many tissues, not just in the small intestine.
Takanaga
H
H
Department of Pharmaceutics, Faculty of Pharmaceutical Sciences, Kanazawa University, Japan.
Tamai
I
I
Inaba
S
S
Sai
Y
Y
Higashida
H
H
Yamamoto
H
H
Tsuji
A
A
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism; D016466:CHO Cells; D002352:Carrier Proteins / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D006224:Cricetinae; D018076:DNA, Complementary / Q000235:genetics*; D005260:Female; D006801:Humans; D007421:Intestine, Small / Q000378:metabolism*; D008969:Molecular Sequence Data; D027501:Monocarboxylic Acid Transporters; D009865:Oocytes / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014982:Xenopus laevis
D002352:Carrier Proteins; D018076:DNA, Complementary; D027501:Monocarboxylic Acid Transporters