Endogenous Piezo1 Can Confound Mechanically Activated Channel Identification and Characterization

Abstract

A gold standard for characterizing mechanically activated (MA) currents is via heterologous expression ofcandidate channels in naive cells. Two recent studies described MA channels using this paradigm. TMEM150c was proposed to be a component of an MA channel partly based on a heterologous expression approach (Hong etal., 2016). In another study, Piezo1's N-terminal "propeller" domain was proposed to constitute an intrinsic mechanosensitive module based on expression of a chimera between a pore-forming domain of the mechanically insensitive ASIC1 channel and Piezo1 (Zhao etal., 2016). When we attempted to replicate these results, we found each construct conferred modest MA currents in a small fraction of naive HEK cells similar to thepublished work. Strikingly, these MA currents were not detected in cells in which endogenous Piezo1 was CRISPR/Cas9 inactivated. These results highlight the importance of choosing cells lacking endogenous MA channels to assay the mechanotransduction properties of various proteins. This Matters Arising paper is in response to Hong etal. (2016) and Zhao etal. (2016) in Neuron. See also the response papers by Hong etal. (2017) and Zhao etal. (2017) published concurrently with this Matters Arising.