Mediates sodium- and chloride-dependent transport of gamma-aminobutyric acid (GABA) (PubMed:8420981, PubMed:22896705, PubMed:30270321). Can also mediate transport of beta-alanine, taurine and hypotaurine and is the major taurine transporter in hepatocytes (PubMed:8420981, PubMed:22896705, PubMed:30270321). 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) Gamma-aminobutyric acid (GABA) transport is inhibited by beta-alanine, taurine, hypotaurine, beta-guanidinopropionic acid, 2,3-diaminopropionic acid, guvacine and nipecotic acid (PubMed:8420981, PubMed:22896705). Beta-alanine transport is inhibited by GABA (PubMed:8420981). Taurine transport is inhibited by GABA, beta-alanine, SNAP-5114, nigericin, nipecotic acid and ouabain (PubMed:22896705). In the kidney, detected at the basolateral membranes of parts of proximal tubules. Expressed at high levels in liver, followed by kidney and leptomeninges, and very low levels in the cerebellum (at protein level). In the brain, detected in some blood vessels (at protein level). In the kidney, expressed in the cortex, including parts of the proximal tubules, but not in the medulla (at protein level). In the liver, highest expression in periportal hepatocytes, with highest density at the vascular side (at protein level). Also detected at low levels in other organs, including skeletal muscle. Abundant in neonatal brain, but not in adult brain. Mutant animals are born at the expected Mendelian ratio. They appear normal, fertile, with a normal life span. Tissue taurine levels are altered, with 50% decrease in the liver and 20% increase in the brain. Belongs to the sodium:neurotransmitter symporter (SNF) (TC 2.A.22) family. SLC6A13 subfamily.