1 Nicotinamide adenine dinucleotide is transported into mammalian mitochondria 2 3 Antonio Davila, Jr. 1,2*, Ling Liu3*, Karthikeyani Chellappa1, Philip Redpath4, Eiko Nakamaru-Ogiso5, Lauren M. 4 Paolella1, Zhigang Zhang6, Marie E. Migaud4,7, Joshua D. Rabinowitz3, and Joseph A. Baur1 5 6 1Department of Physiology, Institute for Diabetes, Obesity, and Metabolism, Perelman School of Medicine, 7 University of Pennsylvania, Philadelphia, PA, USA 8 2PARC, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA 9 3Lewis-Sigler Institute for Integrative Genomics, Department of Chemistry, Princeton University, Princeton NJ 10 4School of Pharmacy, Queen’s University Belfast, Belfast, BT9 7BL, Northern Ireland, UK 11 5Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, 12 Philadelphia, PA, USA 13 6College of Veterinary Medicine, Northeast Agricultural University, Harbin, China 14 7Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA (present location). 15 * These authors contributed equally to this work. 16 17 18 19 20 21 Keywords: NAD, NADH, nicotinamide, niacin, mononucleotide, redox ratio, mitochondrial biogenesis, Krebs cycle, 22 metabolic syndrome 23 24 25 26 27 28 29 30 31 32 33 34 To whom correspondence should be addressed: 35 36 Dr. Joseph A. Baur 37 Associate Professor of Physiology 38 3400 Civic Center Blvd, SCTR 12-114 39 Philadelphia, PA 19066, USA 40 Tel.: (215) 746-4585 41 Fax: (215) 898-5408 42 email:
[email protected] 43 44 45 46 1 47 Abstract 48 49 Mitochondrial NAD levels influence fuel selection, circadian rhythms, and cell survival under stress. It has 50 alternately been argued that NAD in mammalian mitochondria arises from import of cytosolic nicotinamide 51 (NAM), nicotinamide mononucleotide (NMN), or NAD itself.