Intrinsically disordered intracellular domains control key features of the mechanically-gated ion channel PIEZO2

Abstract

A central question in mechanobiology is how mechanical forces acting in or on cells are transmitted to mechanically-gated PIEZO channels that convert these forces into biochemical signals. Here we examined the role of the intracellular domains of PIEZO2, which account for 25% of the channel, and demonstrate that these domains fine-tune properties such as poking and stretch-sensitivity, velocity coding and single channel conductance. Moreover, we show that the intrinsically disordered linker between the transmembrane helices twelve and thirteen (IDR5) is required for the activation of PIEZO2 by cytoskeleton-transmitted forces. The deletion of IDR5 abolishes PIEZO2-mediated inhibition of neurite outgrowth, while it only partially affected its sensitivity to cell indentation and does not alter its stretch sensitivity. Thus, we propose that PIEZO2 is a polymodal mechanosensor that detects different types of mechanical stimuli via different force transmission pathways, which highlights the importance of utilizing multiple complementary assays when investigating PIEZO function.

Membrane curvature governs the distribution of Piezo1 in live cells

“…Lastly, Piezo2 inhibits neurite outgrowth in N2a cells 16 . In addition to membrane curvature, specific Piezo regions and Ca 2+ signaling induced by the activation of Piezo can also play important roles in regulating filopodia formation and growth 16,41,42 . Further studies are required to fully dissect the contribution of each of these variables.…”

“…Secondly, Piezo1 negatively regulates the morphological activity (i.e., number of protrusions) of muscle stem cells 42 . Lastly, Piezo2 inhibits neurite outgrowth in N2a cells 16 . In addition to membrane curvature, specific Piezo regions and Ca 2+ signaling induced by the activation of Piezo can also play important roles in regulating filopodia formation and growth 16,41,42 .…”

Force From Filaments: The Role of the Cytoskeleton and Extracellular Matrix in the Gating of Mechanosensitive Channels

“…In contrast, PIEZO2 is intriguingly known for a preferential response to indentation of the cell membrane, whereas PIEZO1 is sensitive to all forms of mechanical deformation ( Ikeda and Gu, 2014 ; Moroni et al, 2018 ; Shin et al, 2019 ). A battery of data has indicated PIEZO2 is less sensitive to membrane stretch ( Coste et al, 2015 ; Moroni et al, 2018 ; Verkest et al, 2022 ). Shin et al (2019) showed that positive pressures under the cell-attached mode could activate PIEZO2 currents in a Merkel cell line and PIEZO2-overexpressed HEK 293T cells, but negative pressure failed to activate PIEZO2 in these cells, which suggests that not all kinds of membrane stretching can induce PIEZO2 gating.…”

“…The PIEZO2-PIEZO1 beam chimera lost much of its sensitivity to latrunculin A. Verkest et al (2022) reported that an intrinsically disordered domain 5 (IDR5) in the PIEZO2 molecule was required for the interaction between PIEZO2 and the actin cytoskeleton. Deletion of IDR5 specifically reduced membrane indentation-evoked PIEZO2 currents, but showed no effects on negative pressure-evoked PIEZO2 currents.…”

“…The actin cytoskeleton-disrupting drug cytochalasin-D also reduced membrane indentation-evoked current amplitudes of PIEZO2 to the levels of the IDR5-deleted mutant. The authors showed that IDR5 is required for detecting cell-generated forces that activate PIEZO2 via force-from-filament or force-from-lipids- via -filament, but not fore-from-lipids ( Verkest et al, 2022 ). In addition, the presence of some cytoskeletal proteins, such as STOML3, increased the mechanosensitivity of both PIEZO1 and PIEZO2 to membrane tension ( Poole et al, 2014 ).…”