Mediates sodium- and chloride-dependent transport of gamma-aminobutyric acid (GABA) (PubMed:1400419, PubMed:22896705). Mediates transport of taurine and is the major taurine transporter in hepatocytes (PubMed:22896705). Can also mediate transport of beta-alanine and hypotaurine (By similarity). 4-aminobutanoate(out) + chloride(out) + 2 Na(+)(out) = 4-aminobutanoate(in) + chloride(in) + 2 Na(+)(in) chloride(out) + 2 Na(+)(out) + taurine(out) = chloride(in) + 2 Na(+)(in) + taurine(in) beta-alanine(out) + chloride(out) + 2 Na(+)(out) = beta-alanine(in) + chloride(in) + 2 Na(+)(in) chloride(out) + hypotaurine(out) + 2 Na(+)(out) = chloride(in) + hypotaurine(in) + 2 Na(+)(in) GABA transport is inhibited by beta-alanine, L-2,4-Diaminobutyric acid, hypotaurine and nipecotic acid (PubMed:1400419, PubMed:22896705). Taurine transport is inhibited by hypotaurine, beta-alanine and nipecotic acid (PubMed:22896705). Brain, retina, and peripheral tissues. Expressed in hepatocytes (at protein level). Belongs to the sodium:neurotransmitter symporter (SNF) (TC 2.A.22) family. SLC6A13 subfamily.