Ammonia homeostasis is essential for the normal functioning of macro-and microorganisms. The change in concentration of ammonia derivatives in intracellular and extracellular environments is a marker of nitrogen metabolism imbalance. Transport of these molecules is now known to occur by both simple diffusion and special membrane-associated transporters belonging to the Amt/MEP/Rh family. This protein family is subdivided into two subfamilies: the ammonium transporter (AMT)-methylammonium/ammonium permeases (MEP) and the rhesus (Rh) proteins. In this review, we systemize and generalize the long-established and some recent findings on the role of these proteins in nitrogen metabolism in general, and in the ammonia balance in particular. The similarities and differences of these systems in various living beings are discussed. The paper also focuses on the characteristics of several aspects of the classification and on the physiological importance of these proteins and their relationships to certain pathological processes. We also enumerate the prospects and unique challenges of research in this field of science. Deeper theoretical and practical research will provide a better understanding of the mechanisms underlying the structural-functional evolution of ammonia transport proteins, as well as the level of their involvement in the signaling pathways associated with the pathophysiology of nitrogen metabolism.

氨稳态对于宏观微生物和微生物的正常运转至关重要。细胞内和细胞外环境中氨衍生物浓度的变化是氮代谢失衡的标志。现在已知这些分子的转运是通过简单扩散和属于Amt / MEP / Rh家族的特殊膜相关转运蛋白发生的。该蛋白家族分为两个亚家族：铵转运蛋白（AMT）-甲基铵/铵通透酶（MEP）和恒河猴（Rh）蛋白。在这篇综述中，我们对这些蛋白质在氮代谢中的作用，特别是氨平衡中的作用进行了系统化和概括化研究。讨论了这些系统在各种生物中的异同。本文还着重于分类的几个方面的特征以及这些蛋白质的生理重要性及其与某些病理过程的关系。我们还列举了该科学领域的研究前景和独特挑战。更深入的理论和实践研究将使人们更好地了解氨转运蛋白的结构功能进化的潜在机制，以及它们参与与氮代谢的病理生理学相关的信号传导途径的水平。