Involved in the regulation of nitrogen metabolism (By similarity). Regulates the activity of its targets by protein-protein interaction in response to the nitrogen status of the cell (By similarity). Regulates the activity of the ammonia channel Amt3 via direct interaction (Probable). Activity is influenced by intracellular pools of the effector molecules ATP, ADP and 2-oxoglutarate. It senses the cellular nitrogen status through 2-oxoglutarate, and the energy level of the cell by binding both ATP and ADP with different affinities. ATP and 2-oxoglutarate prohibit binding to Amt3. ADP promotes the complex formation. Homotrimer (PubMed:22039461). Interacts and forms a complex with Amt3 (By similarity). Undergoes conformational changes upon binding of effector molecules. Belongs to the P(II) protein family.