Mediates transport of gamma-aminobutyric acid (GABA) together with sodium and chloride and is responsible for the reuptake of GABA from the synapse (PubMed:7960586). The translocation of GABA, however, may also occur in the reverse direction leading to the release of GABA (By similarity). The direction and magnitude of GABA transport is a consequence of the prevailing thermodynamic conditions, determined by membrane potential and the intracellular and extracellular concentrations of Na(+), Cl(-) and GABA (By similarity). Can also mediate sodium- and chloride-dependent transport of hypotaurine but to a much lower extent as compared to GABA (By similarity). 4-aminobutanoate(out) + chloride(out) + 2 Na(+)(out) = 4-aminobutanoate(in) + chloride(in) + 2 Na(+)(in) chloride(out) + hypotaurine(out) + 2 Na(+)(out) = chloride(in) + hypotaurine(in) + 2 Na(+)(in) Inhibited by L-diaminobutyric acid, guvacine, cis-4-hydroxynipecotic acid, nipecotic acid, and 4,5,6,7-tetrahydroisoxazolo [4,5c]-pyridin-3-ol. Interacts (via PDZ domain-binding motif) with PALS1; interaction increases SLC6A1-mediated GABA uptake. Localized at the presynaptic terminals of interneurons. Retinal neurons. This protein is the target of psychomotor stimulants such as amphetamines or cocaine. Belongs to the sodium:neurotransmitter symporter (SNF) (TC 2.A.22) family. SLC6A1 subfamily.