All cells require sustained intracellular energy flux, which is driven by redox chemistry at the subcellular level. Nicotinamide adenine dinucleotide (NAD+), its phosphorylated variant NAD(P)+, and its reduced forms NAD(P)/NAD(P)H are all redox cofactors with key roles in energy metabolism and are substrates for several NAD-consuming enzymes (e.g. poly-ADP ribose polymerases [PARPs], sirtuins, and others). The nicotinamide salvage pathway, constituted by nicotinamide mononucleotide adenylyltransferase (NMNAT) and nicotinamide phosphoribosyltransferase (NAMPT), mainly replenishes NAD+ in eukaryotes. Yet, unlike NMNAT1, NAMPT is not known to be a nuclear protein, prompting the question how the nuclear NAD+ pool is maintained and how it is replenished upon NAD+ consumption. In the present work, using human and murine cells; immunoprecipitation, pulldown, and surface plasmon resonance assays; and immunofluorescence, small-angle X-Ray scattering (SAXS), and MS-based analyses, we report that GAPDH and NAMPT form a stable complex that is essential for nuclear translocation of NAMPT. This translocation furnishes NMN to replenish NAD+ in order to compensate for the activation of NAD-consuming enzymes by stressful stimuli induced by exposure to H2O2 or S-nitrosoglutathione and DNA damage inducers. These results indicate that by forming a complex with GAPDH, NAMPT can translocate to the nucleus and thereby sustain the stress-induced NMN/NAD+ salvage pathway.
A nicotinamide phosphoribosyltransferase-GAPDH interaction sustains the stress-induced NMN/NAD+ salvage pathway in the nucleus / Grolla, Ambra A; Miggiano, Riccardo; Di Marino, Daniele; Bianchi, Michele; Gori, Alessandro; Orsomando, Giuseppe; Gaudino, Federica; Galli, Ubaldina; Del Grosso, Erika; Mazzola, Francesca; Angeletti, Carlo; Guarneri, Martina; Torretta, Simone; Calabrò, Marta; Boumya, Sara; Fan, Xiaorui; Colombo, Giorgia; Travelli, Cristina; Rocchio, Francesca; Aronica, Eleonora; Wohlschlegel, James A; Deaglio, Silvia; Rizzi, Menico; Genazzani, Armando A; Garavaglia, Silvia. - In: THE JOURNAL OF BIOLOGICAL CHEMISTRY. - ISSN 0021-9258. - STAMPA. - 295:11(2020), pp. 3635-3651. [10.1074/jbc.RA119.010571]