1220831-36-6Relevant articles and documents
Agonist-mediated switching of ion selectivity in TPC2 differentially promotes lysosomal function
Gerndt, Susanne,Chen, Cheng-Chang,Chao, Yu-Kai,Yuan, Yu,Burgstaller, Sandra,Rosato, Anna Scotto,Krogsaeter, Einar,Urban, Nicole,Jacob, Katharina,Nguyen, Ong Nam Phuong,Miller, Meghan T.,Keller, Marco,Vollmar, Angelika M.,Gudermann, Thomas,Zierler, Susanna,Schredelseker, Johann,Schaefer, Michael,Biel, Martin,Malli, Roland,Wahl-Schott, Christian,Bracher, Franz,Patel, Sandip,Grimm, Christian
, (2020/05/08)
Ion selectivity is a defining feature of a given ion channel and is considered immutable. Here we show that ion selectivity of the lysosomal ion channel TPC2, which is hotly debated (Calcraft et al., 2009; Guo et al., 2017; Jha et al., 2014; Ruas et al., 2015; Wang et al., 2012), depends on the activating ligand. A high-throughput screen identified two structurally distinct TPC2 agonists. One of these evoked robust Ca2+-signals and non-selective cation currents, the other weaker Ca2+-signals and Na+-selective currents. These properties were mirrored by the Ca2+- mobilizing messenger, NAADP and the phosphoinositide, PI(3,5)P2, respectively. Agonist action was differentially inhibited by mutation of a single TPC2 residue and coupled to opposing changes in lysosomal pH and exocytosis. Our findings resolve conflicting reports on the permeability and gating properties of TPC2 and they establish a new paradigm whereby a single ion channel mediates distinct, functionally-relevant ionic signatures on demand.
