Nitrogen is critical for cell growth, proliferation, and function. Amino acid (AA) catabolism is a major source of intracellular nitrogen for biosynthesis but also generates the nitrogen-containing molecule ammonia (NH3+), which can accumulate to toxic levels in a cell if not exported to the circulation and detoxified by the urea cycle in the liver. In a recent paper in Nature Immunology, Tang et al. [1] discovered a functional urea cycle in memory T cells, which metabolizes ammonia, prevents its toxic accumulation.
展开▼
