Molecular cloning and functional characterization of glycine transporter of Clonorchis sinensis

초록

All living organisms need amino acids to sustain their life. Amino acids are organic compounds that contain amino and carboxylate functional groups, along with a side chain specific to each amino acid. Ingested proteins are digested with amino acids. Because they have charged functional groups, amino acid transporter proteins are needed for movement across the plasma membrane. Amino acid transporters belonging to the solute carrier superfamily play very important roles in nutrient uptake, neurotransmitter recycling, cell redox balance, cell signaling and regulation of cell volume. Here we report on the isolation of a complementary DNA of sodium-and chloride-dependent glycine. We could find a candidate of Clonorchis sinensis glycine transporter (GAA48917, CsGLYT) from the NCBI database. Full-length cDNA was cloned by overlap extension reverse transcription-polymerase chain reaction from adult Clonorchis sinensis. The open reading frame of CsGLYT consists of 2397 base pairs that encoded a 799-amino acid residue protein. Hydropathy analysis suggested that CsGLYT possesses 12 putative membrane-spanning domains. When expressed in Xenopus oocytes, CsGLYT mediated the transport of radiolabeled glycine in a expression time-, incubation time- and sodium-dependent manner. The CsGLYT showed no exchanger properties by efflux experiments.