Published online
doi:10.1083/jcb.200904073
The Journal of Cell Biology, Vol. 186, No. 2, 201-209
The Rockefeller University Press, 0021-9525 $30.00
© Brailoiu et al.
Essential requirement for two-pore channel 1 in NAADP-mediated calcium signaling
Eugen Brailoiu1,
Dev Churamani2,
Xinjiang Cai3,
Michael G. Schrlau4,
G. Cristina Brailoiu1,
Xin Gao1,
Robert Hooper2,
Michael J. Boulware5,
Nae J. Dun1,
Jonathan S. Marchant5, and
Sandip Patel2
1 Department of Pharmacology, Temple University School of Medicine, Philadelphia, PA 19140
2 Department of Cell and Developmental Biology, University College London, London WC1E 6BT, England, UK
3 Division of Cardiology, Department of Medicine, Duke University Medical Center, Durham, NC 27710
4 Department of Mechanical Engineering and Applied Mechanics, University of Pennsylvania, Philadelphia, PA 19104
5 Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455
Correspondence to Sandip Patel: patel.s{at}ucl.ac.uk
Nicotinic acid adenine dinucleotide phosphate (NAADP) is a widespread and potent calcium-mobilizing messenger that is highly unusual in activating calcium channels located on acidic stores. However, the molecular identity of the target protein is unclear. In this study, we show that the previously uncharacterized human two-pore channels (TPC1 and TPC2) are endolysosomal proteins, that NAADP-mediated calcium signals are enhanced by overexpression of TPC1 and attenuated after knockdown of TPC1, and that mutation of a single highly conserved residue within a putative pore region abrogated calcium release by NAADP. Thus, TPC1 is critical for NAADP action and is likely the long sought after target channel for NAADP.
Abbreviations used in this paper: HEK, human embryonic kidney; mRFP, monomeric RFP; NAADP, nicotinic acid adenine dinucleotide phosphate; shRNA, short hairpin RNA; TPC, two-pore channel.
© 2009 Brailoiu et al.
This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.jcb.org/misc/terms.shtml). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 3.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/3.0/).

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