A fluorescent sensor for NAD+ in living cells

Metabolism Roles of cellular nicotinamide adenine dinucleotide (NAD+) in metabolism, aging, and disease have garnered much interest, but methods have been lacking to measure the amounts of NAD+ in living cells. Cambronne et al. developed a genetically encoded biosensor that can be used to monitor concentrations of free NAD+ in various compartments of a cell (see the Perspective by Guarente). Such concentrations of NAD+ appear to be important in regulating the activity of NAD+-consuming enzymes such as sirtuins and ADP-ribosyltransferases. The authors used the sensor to demonstrate that NAD+ concentrations in mitochondria of cultured human cells can be controlled by multiple mechanisms. Science , this issue p. [1474][1]; see also p. [1396][2] [1]: /lookup/doi/10.1126/science.aad5168 [2]: /lookup/doi/10.1126/science.aag1718