Amino acid homeostasis is maintained by import, export, oxidation, and synthesis of nonessential amino acids, and by the synthesis and breakdown of protein. These processes work in conjunction with regulatory elements that sense amino acids or their metabolites. During and after nutrient intake, amino acid homeostasis is dominated by autoregulatory processes such as transport and oxidation of excess amino acids. Amino acid deprivation triggers processes such as autophagy and the execution of broader transcriptional programs to maintain plasma amino acid concentrations. Amino acid transport plays a crucial role in the absorption of amino acids in the intestine, the distribution of amino acids across cells and organs, the recycling of amino acids in the kidney, and the recycling of amino acids after protein breakdown.

中文翻译：

---

以氨基酸转运为重点的哺乳动物细胞中的氨基酸稳态

氨基酸稳态通过非必需氨基酸的输入、输出、氧化和合成，以及蛋白质的合成和分解来维持。这些过程与感知氨基酸或其代谢物的调节元件协同工作。在营养摄入期间和之后，氨基酸稳态受自动调节过程控制，例如过量氨基酸的运输和氧化。氨基酸剥夺会触发诸如自噬和执行更广泛的转录程序以维持血浆氨基酸浓度等过程。氨基酸转运对氨基酸在肠道的吸收、氨基酸在细胞和器官中的分布、氨基酸在肾脏的再循环以及蛋白质分解后氨基酸的再循环等过程起着至关重要的作用。