Loss-of-Function Piezo1 Mutations Display Altered Stability Driven by Ubiquitination and Proteasomal Degradation.

Zijing Zhou,Boris Martinac,Charles D Cox,Jinyuan Vero Li

doi:10.3389/fphar.2021.766416

Zijing Zhou, Boris Martinac + Show 2 more

Open Access

https://doi.org/10.3389/fphar.2021.766416

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Abstract

Missense mutations in the gene that encodes for the mechanically-gated ion channel Piezo1 have been linked to a number of diseases. Gain-of-function variants are linked to a hereditary anaemia and loss-of-function variants have been linked to generalized lymphatic dysplasia and bicuspid aortic valve. Two previously characterized mutations, S217L and G2029R, both exhibit reduced plasma membrane trafficking. Here we show that both mutations also display reduced stability and higher turnover rates than wild-type Piezo1 channels. This occurs through increased ubiquitination and subsequent proteasomal degradation. Congruent with this, proteasome inhibition using N-acetyl-l-leucyl-l-leucyl-l-norleucinal (ALLN) reduced the degradation of both mutant proteins. While ALLN treatment could not rescue the function of S217L we show via multiple complementary methodologies that proteasome inhibition via ALLN treatment can not only prevent G2029R turnover but increase the membrane localized pool of this variant and the functional Piezo1 mechanosensitive currents. This data in combination with a precision medicine approach provides a new potential therapeutic avenue for the treatment of Piezo1 mediated channelopathies.

Highlights

Mechanosensitive (MS) ion channels are a structurally diverse class of cellular sensors that decode mechanical cues (Martinac and Cox, 2017; Cox et al, 2019; Poole, 2021; Syeda, 2021)
Given that ALLN increased the membrane targeting of G2029R Piezo1 we examined whether the increased membrane localized G2029R Piezo1 correlated with an increase in mechanically evoked currents
PIEZO1 variants have been linked to a number of pathologies (Zarychanski et al, 2012; Albuisson et al, 2013; Bae et al, 2013; Fotiou et al, 2015; Lukacs et al, 2015; Faucherre et al, 2020)

Summary

Introduction

Mechanosensitive (MS) ion channels are a structurally diverse class of cellular sensors that decode mechanical cues (Martinac and Cox, 2017; Cox et al, 2019; Poole, 2021; Syeda, 2021). The mechanosensitive channel Piezo has an emerging role in cardiovascular biology (Li et al, 2014; Rode et al, 2017; Douguet et al, 2019; Jiang et al, 2021; Yu et al, 2021) and is central in force sensing by vascular endothelial cells (Li et al, 2014; Ranade et al, 2014; Rode et al, 2017; Albarrán-Juárez et al, 2018; Nonomura et al, 2018) This channel responds to both membrane tension (Lewis and Grandl, 2015; Cox et al, 2016; Syeda et al, 2016) and shear stress (Ranade et al, 2014; Albarrán-Juárez et al, 2018; Maneshi et al, 2018; Lai et al, 2021) (whether these are separate molecular mechanisms remains to be determined) and is important in the development of valves in different tissues including the lymphatic system (Nonomura et al, 2018) and heart (Duchemin et al, 2019; Faucherre et al, 2020). Using the extensive published information from the Kv11.1 channel literature we attempted through low temperature and pharmacological means (Robertson and January 2006; Smith et al, 2013; Anderson et al, 2014) to rescue surface expression and function of Piezo mutants but neither approach was successful

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