NAADP: A New Second Messenger Comes of Age

Abstract

Nicotinic acid adenine dinucleotide phosphate (NAADP) is one of the most potent stimulators of intracellular Ca²⁺ mobilization in a variety of cell types. Its role in physiological processes is increasingly demonstrated by NAADP increases following cellular stimulation. As a second messenger NAADP shows unique features such as the ability to mobilize Ca²⁺ from stores that are physically distinct from those connected to the Ca²⁺ channels located in the endoplasmic reticulum, namely, the inositol-1,4,5-trisphosphate and the cyclic-ADP-ribose/ ryanodine receptors. Furthermore, the NAADP-induced self-inactivation mechanism is suggestive of an irreversible binding of NAADP to its putative receptor.