Fig. 2.

Glutaminolysis at different stages of the metabolism. Glutamate is converted to the TCA cycle intermediate α-KG and the corresponding amino acid. The newly formed citrate exits the mitochondria where it is used to synthesize fatty acids and amino acids, transfer glutamate to the cytoplasm, and synthesize GSH, which is critical for maintaining redox homeostasis and protecting cells from oxidative stress. a broad upregulation of biosynthetic pathways characterizes proliferative and metastatic metabolism by glutamine. (A) In quiescent metabolism, glutamine metabolism is maintained at a low level. (B) In the proliferative stage, glutamine consumption has increased and more GSH is needed to counteract oxidative stress. (C) When cancer cells transform to the metastatic stage, more lipids and nucleotides are synthesized to adapt to the synthetic needs