2010 - Characterization of two pore channel 2 (TPCN2) -mediated Ca2+ currents in isolated lysosomes
Port-a-Patch publication in The Journal of Biological Chemistry (2010)
Schieder M., Rötzer K., Brüggemann A., Biel M., Wahl-Schott C.A.
The Journal of Biological Chemistry (2010) 285(28):21219–21222
Two-pore channels (TPCNs) have been proposed to form lysosomal Ca2+ release channels that are activated by nicotinic acid adenine dinucleotide phosphate. Here, we employ a glass chip-based method to record for the first time nicotinic acid adenine dinucleotide phosphate -dependent currents through a two-pore channel (TPCN2) from intact lysosomes. We show that TPCN2 is a highly selective Ca2+ channel that is regulated by intralysosomal pH. Using site-directed mutagenesis, we identify an amino acid residue in the putative pore region that is crucial for conferring high Ca2+ selectivity. Our glass chip-based method will provide electrophysiological access not only to lysosomal TPCN channels but also to a broad range of other intracellular ion channels.