Table 1.

Metabolic regulators of T cell development and quiescence.

	Effector T cells (Th1, Th2, Th17 and CTL)	Naïve T cells	Tregs	Memory CD8+ T cells
Preferred metabolic mode	Anabolic metabolism		Catabolic metabolism
Primary source of energy	Aerobic glycolysis glutaminolysis		Fatty acid oxidation
Metabolic transporter	CD98 (amino acid transporter) ASCT (amino acid transporter) Glut1 (glucose transporter)		Low nutrient uptake
Metabolic kinases	AMPK↓ mTORC1/2↑	N/A	AMPK↑	mTORC1/2↓
Metabolic transcription factors	Myc HIF-1α IRF4 AP4 SREBP	TSC KLF FoxO Foxp Tob	HIF-1α	ACC1

Distinct stages of T cell development correlate with different metabolic states. Naïve, Tregs and memory T cells can be grouped for their reliance on catabolic metabolism and fatty acid oxidation. These cells also have low rates of nutrient uptake, and naïve T cells express high levels of Tob, KLF and Fox that maintain quiescence and survival. Tregs and memory T cells have high AMPK and low mTOR activity, and HIF-1α can post-transcriptionally regulate Treg development. Effector CD4+ and CD8+ T cells utilize aerobic glycolysis and glutaminolysis for their energy supply, and prefer anabolic metabolism in order to synthesize macromolecules. They express high levels of glucose and amino acid transporters, and high rates of nutrient uptake lead to high mTOR and low AMPK activity. At the same time, effector T cells express high levels of Myc and HIF-1α that initiate metabolic and transcriptional changes.

Abbreviations: helper CD4+ T cell type-1 (Th1), type-2 (Th2), type-17 (Th17), regulatory T cells (Tregs), cytolytic T cells (CTLs).