Solute Carrier Family 6, Member 12 (SLC6A12)

The predicted 614-amino acid human protein has the typical structure of neurotransmitter transporters, with 12 transmembrane domains and a large extracellular loop between the third and fourth transmembrane domains. Northern blot analysis indicated that BGT1 is expressed as several mRNAs in human kidney and other tissues. The human protein shares 91% and 87% sequence identity with canine and mouse BGT1, respectively. Heterologous expression of human BGT1 in mammalian cells conferred high-affinity GABA uptake. BGT1 protein exhibited chloride- and sodium-dependent transport of both betaine and the neurotransmitter GABA. Northern blot analysis revealed that BGT1 expression is limited to the canine kidney medulla and is induced in MDCK cells by hypertonicity.