Transporter protein required for ammonia export. Induced in rho(0) cells, probably to eliminate the excess ammonia that arises because of a potential defect in ammonia assimilation in those cells. Localizes to large detergent resistant patches of the cell membrane (DRM) enriched in ergosterol and sphingolipids. Expression is under the control of the ADR1, CAT8, and GCN4 transcription factors. Also induced by external ammonia and in rho(0) cells. Belongs to the acetate uptake transporter (AceTr) (TC 2.A.96) family.