The phosphate makes a difference: cellular functions of NADP.
Recent research has unraveled a number of unexpected functions of the pyridine nucleotides. In this review, we will highlight the variety of known physiological roles of NADP. In its reduced form (NADPH), this molecule represents a universal electron donor, not only to drive biosynthetic pathways. Perhaps even more importantly, NADPH is the unique provider of reducing equivalents to maintain or regenerate the cellular detoxifying and antioxidative defense systems. The roles of NADPH in redox sensing and as substrate for NADPH oxidases to generate reactive oxygen species further extend its scope of functions. NADP(+), on the other hand, has acquired signaling functions. Its conversion to second messengers in calcium signaling may have critical impact on important cellular processes. The generation of NADP by NAD kinases is a key determinant of the cellular NADP concentration. The regulation of these enzymes may, therefore, be critical to feed the diversity of NADP-dependent processes adequately. The increasing recognition of the multiple roles of NADP has thus led to exciting new insights in this expanding field.
Agledal
Line
L
Department of Molecular Biology, University of Bergen, N-5020 Bergen, Norway.
Niere
Marc
M
Ziegler
Mathias
M
D000818:Animals; D020013:Calcium Signaling / Q000502:physiology; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D006801:Humans; D009244:NAD+ Nucleosidase / Q000378:metabolism; D009249:NADP / Q000502:physiology*; D019255:NADPH Oxidases / Q000378:metabolism; D018384:Oxidative Stress; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000378:metabolism; D010944:Plants / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
D017382:Reactive Oxygen Species; D009249:NADP; D003577:Cytochrome P-450 Enzyme System; D019255:NADPH Oxidases; D017853:Phosphotransferases (Alcohol Group Acceptor); C021844:NAD kinase; D009244:NAD+ Nucleosidase