Involved in the uptake of ammonium/ammonia (NH(4)(+)/NH(3)) (By similarity). Transport is electrogenic (By similarity). Activity is regulated by the nitrogen regulatory protein GlnK1 via direct interaction (PubMed:17203075). Formation of the GlnK1/Amt1 complex is decreased in the presence of Mg-ATP or 2-oxoglutarate. The presence of both effectors abolishes the formation of the complex (PubMed:17203075). Homotrimer (PubMed:17203075). Interacts and forms a complex with GlnK1 (PubMed:17203075). Belongs to the ammonia transporter channel (TC 1.A.11.2) family.