TY - JOUR
T1 - TPC proteins are phosphoinositide- Activated sodium-selective ion channels in endosomes and lysosomes
AU - Wang, Xiang
AU - Zhang, Xiaoli
AU - Dong, Xian Ping
AU - Samie, Mohammad
AU - Li, Xinran
AU - Cheng, Xiping
AU - Goschka, Andrew
AU - Shen, Dongbiao
AU - Zhou, Yandong
AU - Harlow, Janice
AU - Zhu, Michael X.
AU - Clapham, David E.
AU - Ren, Dejian
AU - Xu, Haoxing
N1 - Funding Information:
This work was supported by NIH R01 grants (NS062792 to H.X., NS055293 to D.R., GM081658 to M.X.Z., and HHMI to D.E.C.) and a Sloan Research Fellowship (to H.X.). We thank the Gene Manipulation Facility of Children's Hospital Boston (TPC1) and the Transgenic and Chimera Mouse Facility at the University of Pennsylvania (TPC2) for embryonic stem cell injection. The authors are listed in the order of their institutions; X.W. initiated the project; X.W., X.Z., and X.-p.D. performed the electrophysiology experiments; X.W. also performed the Ca 2+ imaging experiments; M.S. and A.G. performed the ionic composition experiments; X.L., X.C., D.S., and M.X.Z. contributed the reagents; D.R. and J.H. developed the TPC1, TPC2 knockout mouse lines and the hTPC1, hTPC2, hTPC1ΔN, and hTPC2ΔN constructs; Y.Z. measured the glucose- and NAADP-induced Ca 2+ responses in the TPC mutant islets compared with wild-type; development of the TPC1 knockout was carried out by D.R. in the laboratory of D.E.C.; and H.X. and D.E.C. wrote the paper with input from all authors. We are grateful to Drs. Susan Slaugenhaupt and James Slama for sharing reagents; Drs. Ted Huston, Hollis Showalter, Yafei Jin, Leslie Satin, Jianhua Ren, Peter Arvan, and Gautam Rajpal for assistance; and Dr. Richard Hume for comments on an earlier version of the manuscript. We appreciate the encouragement and helpful comments from other members of the Xu, Ren, and Clapham laboratories.
PY - 2012/10/12
Y1 - 2012/10/12
N2 - Mammalian two-pore channel proteins (TPC1, TPC2; TPCN1, TPCN2) encode ion channels in intracellular endosomes and lysosomes and were proposed to mediate endolysosomal calcium release triggered by the second messenger, nicotinic acid adenine dinucleotide phosphate (NAADP). By directly recording TPCs in endolysosomes from wild-type and TPC double-knockout mice, here we show that, in contrast to previous conclusions, TPCs are in fact sodium-selective channels activated by PI(3,5)P2 and are not activated by NAADP. Moreover, the primary endolysosomal ion is Na+, not K+, as had been previously assumed. These findings suggest that the organellar membrane potential may undergo large regulatory changes and may explain the specificity of PI(3,5)P2 in regulating the fusogenic potential of intracellular organelles.
AB - Mammalian two-pore channel proteins (TPC1, TPC2; TPCN1, TPCN2) encode ion channels in intracellular endosomes and lysosomes and were proposed to mediate endolysosomal calcium release triggered by the second messenger, nicotinic acid adenine dinucleotide phosphate (NAADP). By directly recording TPCs in endolysosomes from wild-type and TPC double-knockout mice, here we show that, in contrast to previous conclusions, TPCs are in fact sodium-selective channels activated by PI(3,5)P2 and are not activated by NAADP. Moreover, the primary endolysosomal ion is Na+, not K+, as had been previously assumed. These findings suggest that the organellar membrane potential may undergo large regulatory changes and may explain the specificity of PI(3,5)P2 in regulating the fusogenic potential of intracellular organelles.
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U2 - 10.1016/j.cell.2012.08.036
DO - 10.1016/j.cell.2012.08.036
M3 - Article
C2 - 23063126
AN - SCOPUS:84867565289
SN - 0092-8674
VL - 151
SP - 372
EP - 383
JO - Cell
JF - Cell
IS - 2
ER -