This transmembrane region is found in many amino acid transporters including UNC-47 and MTR. UNC-47 encodes a vesicular amino butyric acid (GABA) transporter, (VGAT). UNC-47 is predicted to have 10 transmembrane domains Swiss:P34579 [1]. MTR is a N system amino acid transporter system protein involved in methyltryptophan resistance Swiss:P38680. Other members of this family include proline transporters and amino acid permeases.

1: Identification and characterization of the vesicular GABA transporter. McIntire SL, Reimer RJ, Schuske K, Edwards RH, Jorgensen EM; Nature 1997;389:870-876. PMID:9349821