Involved in the uptake of ammonium/ammonia (NH(4)(+)/NH(3)) (By similarity). Transport is electrogenic (By similarity). Homotrimer (By similarity). Interacts with both GlnK1 and GlnK2 after ammonium shock (PubMed:24039236). Interaction is rapid, reversible and dependent on nitrogen source (PubMed:24039236). Highly expressed during ammonium starvation under nitrate-rich conditions. Belongs to the ammonia transporter channel (TC 1.A.11.2) family.