Most sequenced members are from animals, but bacterial and archaeal homologues have been sequenced.
These proteins are generally of 600-700 amino acyl residues in length and probably possess 12 transmembrane helical spanners. Recently, several members of the NSS family have been shown to exhibit channel-like properties under certain experimental conditions. Thus, sizable unitary ionic currents have been reported for membrane patches containing either the g -aminobutyrate, norepinephrine or serotonin transporter. Evidence shows that these channels can accomodate neurotransmitters as well as inorganic ions. These observations suggest that, as has been demonstrated for carriers of a few other families, neurotransmitter transporters can be induced for function as voltage-gated channels.