Nitrogen, a gasocrine signal, is likely sensed via ammonia-sensing gasoreceptors

Understanding how organisms communicate is a fundamental question in biology and marks an evolutionarily important milestone. Organisms largely communicate via gas-based gasocrine, light-based photocrine, sound-based sonocrine, mineral/metal-based metallocrine, water-based aquacrine, and thermal radiation-based thermocrine signaling. Due to the importance of gasocrine signaling for biotic life, how organisms can sense gasocrine signals such as O₂ (oxygen) via O₂-sensing protein gasoreceptors (or sensors) has been largely investigated in microorganisms. Even though nitrogen (N₂) is also one of the gasocrine signals, to the best of my knowledge and few other leading experts on nitrogen fixation and nitric oxide-dependent signaling, how organisms sense nitrogen per se is still unknown. In my opinion, just as the FeMo (iron-molybdenum) cofactor in nitrogenase can directly bind N₂, and convert it to ammonia (NH₃), other FeMo-binding proteins with additional signaling domains are putative candidates for N₂-sensing gasoreceptors that mediate N₂-based gasocrine signaling. We must also consider the possibility of promiscuity of gasocrine signal-gasoreceptor and/or co-factor binding as N₂ is not the only FeMO-binding gas. Additionally, similar to how lactose levels are sensed as allolactose via the lac repressor (a sugar-sensing swodkoreceptor), N₂ may also be sensed as NH₃ via NH₃-sensing receptors (Drosophila Ir92a?, but what about cytoplasmic like sGC for NO?). Identifying how cells sense N₂ per se or NH₃ may help us understand gasocrine signaling, causes for civilizational diseases etc.