cDNA Cloning and Functional Characterization of Rat Intestinal Monocarboxylate Transporter

• Published in: Biochemical and biophysical research communications Vol. 217; no. 1; pp. 370 - 377
• Main Authors: Takanaga, H., Tamai, I., Inaba, S., Sai, Y., Higashida, H., Yamamoto, H., Tsuji, A.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 05.12.1995
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Brain - metabolism; Carrier Proteins - genetics; Carrier Proteins - metabolism; CHO Cells; Cloning, Molecular; Cricetinae; DNA, Complementary - genetics; Female; Humans; Intestine, Small - metabolism; Molecular Sequence Data; Monocarboxylic Acid Transporters; Oocytes - metabolism; Rats; Rats, Wistar; Xenopus laevis
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1006/bbrc.1995.2786

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.