title: Linking NAADP to ion channel activity: a unifying hypothesis.
abstract: Nicotinic acid adenine dinucleotide phosphate (NAADP) is a potent Ca(2+)-releasing second messenger that might regulate different ion channels, including the ryanodine receptor, two-pore channels, and TRP-ML1 (transient receptor potential channel, subtype mucolipin 1), a Ca(2+) channel localized to lysosomes. New evidence suggests that a 22- and 23-kilodalton pair of proteins could be the receptor for NAADP. Labeling of NAADP binding proteins was independent of overexpression or knockout of two-pore channels, indicating that two-pore channels, although regulated by NAADP, are not the NAADP receptors. I propose that NAADP binding proteins could bind to different ion channels and thus may explain how NAADP regulates diverse ion channels.
authors.affiliation: The Calcium Signalling Group, Department of Biochemistry and Signal Transduction, Centre of Experimental Medicine, University Medical Centre Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany. guse@uke.de
authors.forename: Andreas H
authors.initials: AH
authors.lastname: Guse
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D008247:Lysosomes / Q000235:genetics / Q000378:metabolism*; D009249:NADP / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism; D015290:Second Messenger Systems / Q000502:physiology*; D050051:Transient Receptor Potential Channels / Q000235:genetics / Q000378:metabolism*
chemical_list: C416674:MCOLN1 protein, human; D050051:Transient Receptor Potential Channels; D009249:NADP; C024376:NAADP; D002118:Calcium