UCL Division of Biosciences


Prof Sandip Patel’s lab publishes paper with collaborators in eLife

12 November 2020

Agonist-mediated switching of ion selectivity in TPC2 differentially promotes lysosomal function


Congratulations to Yu (Cara) Yuan, a finishing PhD student in the Patel lab, who has had her joint first author paper with collaborators in Germany published in eLife. This work also formed the basis of a successful project grant funded by the BBSRC in the last round.

Abstract 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.

To learn more about the work of Prof Patel's lab please visit the website