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The two-pore channel TPCN2 mediates NAADP-dependent Ca(2+)-release from lysosomal stores
Second messenger-induced Ca(2+)-release from intracellular stores plays a key role in a multitude of physiological processes. In addition to 1,4,5-inositol trisphosphate (IP(3)), Ca(2+), and cyclic ADP ribose (cADPR) that trigger Ca(2+)-release from the endoplasmatic reticulum (ER), nicotinic acid a...
Autores principales: | , , , , , , , , , |
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Formato: | Texto |
Lenguaje: | English |
Publicado: |
Springer-Verlag
2009
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2719734/ https://www.ncbi.nlm.nih.gov/pubmed/19557428 http://dx.doi.org/10.1007/s00424-009-0690-y |
Sumario: | Second messenger-induced Ca(2+)-release from intracellular stores plays a key role in a multitude of physiological processes. In addition to 1,4,5-inositol trisphosphate (IP(3)), Ca(2+), and cyclic ADP ribose (cADPR) that trigger Ca(2+)-release from the endoplasmatic reticulum (ER), nicotinic acid adenine dinucleotide phosphate (NAADP) has been identified as a cellular metabolite that mediates Ca(2+)-release from lysosomal stores. While NAADP-induced Ca(2+)-release has been found in many tissues and cell types, the molecular identity of the channel(s) conferring this release remained elusive so far. Here, we show that TPCN2, a novel member of the two-pore cation channel family, displays the basic properties of native NAADP-dependent Ca(2+)-release channels. TPCN2 transcripts are widely expressed in the body and encode a lysosomal protein forming homomers. TPCN2 mediates intracellular Ca(2+)-release after activation with low-nanomolar concentrations of NAADP while it is desensitized by micromolar concentrations of this second messenger and is insensitive to the NAADP analog nicotinamide adenine dinucleotide phosphate (NADP). Furthermore, TPCN2-mediated Ca(2+)-release is almost completely abolished when the capacity of lysosomes for storing Ca(2+) is pharmacologically blocked. By contrast, TPCN2-specific Ca(2+)-release is unaffected by emptying ER-based Ca(2+) stores. In conclusion, these findings indicate that TPCN2 is a major component of the long-sought lysosomal NAADP-dependent Ca(2+)-release channel. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00424-009-0690-y) contains supplementary material, which is available to authorized users. |
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