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  • An optically controlled probe identifies lipid-gating fenestrations within the TRPC3 channel.

An optically controlled probe identifies lipid-gating fenestrations within the TRPC3 channel.

Nature chemical biology (2018-03-21)
Michaela Lichtenegger, Oleksandra Tiapko, Barbora Svobodova, Thomas Stockner, Toma N Glasnov, Wolfgang Schreibmayer, Dieter Platzer, Gema Guedes de la Cruz, Sarah Krenn, Romana Schober, Niroj Shrestha, Rainer Schindl, Christoph Romanin, Klaus Groschner
ABSTRACT

Transient receptor potential canonical (TRPC) channels TRPC3, TRPC6 and TRPC7 are able to sense the lipid messenger diacylglycerol (DAG). The DAG-sensing and lipid-gating processes in these ion channels are still unknown. To gain insights into the lipid-sensing principle, we generated a DAG photoswitch, OptoDArG, that enabled efficient control of TRPC3 by light. A structure-guided mutagenesis screen of the TRPC3 pore domain unveiled a single glycine residue behind the selectivity filter (G652) that is exposed to lipid through a subunit-joining fenestration. Exchange of G652 with larger residues altered the ability of TRPC3 to discriminate between different DAG molecules. Light-controlled activation-deactivation cycling of TRPC3 channels by an OptoDArG-mediated optical 'lipid clamp' identified pore domain fenestrations as pivotal elements of the channel´s lipid-sensing machinery. We provide evidence for a novel concept of lipid sensing by TRPC channels based on a lateral fenestration in the pore domain that accommodates lipid mediators to control gating.

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GSK1702934A, ≥98% (HPLC)
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