Glycine Transporter 2 (GLYT2)

GLYT2 is a membrane protein which recaptures glycine, a major inhibitory transmitter in the spinal cord and brainstem. GlyT2 is a specific marker of glycinergic neurons and a member of the Na+ and Cl--coupled transporter family SLC6. Glycine uptake mediated by GlyT2 is electrogenic, coupled to three Na+ and one Cl-. In humans, GlyT2 is encoded by the SLC6A5 gene. Inactivation of GlyT2 in knockout mice is lethal during the second post-natal week as the absence of GlyT2 disrupts inhibitory transmission by reducing glycine release. Mutations in SLC6A5 gene are responsible for a presynaptic form of hyperekplexia, a genetic disease causing increased startle reflex. GlyT2 main physiological role is to recapture glycine released in the synaptic cleft and to maintain high glycine concentration in the presynaptic neuron.