The enzyme nicotinate phosphoribosyltransferase (NAPRT) mediates the rate-limiting step in NAD salvage pathway starting from nicotinic acid. Here the authors show that NAPRT can be detected extracellularly, binds to Toll like receptor 4, and activates NF-kB signaling and cytokine production in macrophage via NAD synthesis-independent pathways.
- Antonella Managò
- Valentina Audrito
- Silvia Deaglio