Fig. 1.

Schematic diagram summarizing the bridge between amino acid metabolism and T cell. A In the TME, T cells compete with tumor cells for amino acids. B Amino acid metabolism mainly affects T cell immunity through three aspects, including amino acid depletion caused by nutrient competition, toxic metabolites and crosstalk with glucose metabolism and lipid metabolism. Among them, amino acid depletion plays a role in T cell immunity through multiple mechanisms including mTOR, GCN2, PD-1/PD-L1, epigenetic and post-translational modifications. C Amino acid metabolism can affect glucose metabolism and lipid metabolism. On the one hand, amino acids regulate the activity of enzymes related to glucose metabolism or glucose transport. On the other hand, the intermediates of amino acid metabolism can directly act as substrates for glucose metabolism or lipid metabolism. Abbreviations: TME, tumor microenvironment; ONOO-, peroxynitrite; IL-2R, IL-2 receptor; PTMs, post-translational modifications; TCA cycle, tricarboxylic acid cycle; α-KG, α-ketoglutarate; OXPHOS, oxidative phosphorylation; GLUT, glucose transporter; PKM2, pyruvate kinase isozymes M2; PEP, phosphoenolpyruvate; LDH-A, lactate dehydrogenase A; IDO1, indoleamine 2, 3-dioxygenase 1