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Fig. 1. Hypothetical schematic model for mechanosensing mechanisms of various types of mechanosensors. (A) The cytoskeletal proteins linked to the actin cytoskeleton (F-actin) and adhesive structures that can undergo structural changes in response to mechanical force. The structural change can expose a binding site for other proteins to interact with, which can induce biochemical signaling. (B) Force acting on the ECM-tethered latency-associated peptide (LAP) by cells via integrin can induce a structural change in LAP. Due to the structural change, transforming growth factor (TGF) β can be released from the LAP complex. RGD; Arg-Gly-Asp (integrin binding site), ECM; extracellular matrix. (C) A stretchgated ion channel in Drosophila, NOMPC (no mechanoreceptor potential C), embedded in the membrane. Two of its four subunits are shown. S6 helices from each subunit block the passage of ions. These helices are linked to TRP domains that are captured by the cytoplasmic domains of the channel (left). The mechanical force that can stretch the cytoplasmic domain tethered to the microtubule can induce disposition of the TRP domains, which in turn induce structural changes in the S6 helices, leading to the opening of the channel (right). (D) The closed conformation of the TRAAK channel adopts a wedge shape, causing distortion of the lipid bilayer nearby (left). The open conformation of the channel adopts a cylinder shape (right). The projection areas of the cross-sections of the channel (yellow dotted lines) are shown in both the conformations. (E) Schematic illustrations of two subunits of Piezo1 are shown. Each of its three subunits has a curved conformation in the lipid bilayer, making a ‘dimple’ on the membrane (left). The central pore is suggested to be opened by tension in the lipid bilayer, which may flatten out the subunits (right).
BMB Reports 2018;51:623~629 https://doi.org/10.5483/BMBRep.2018.51.12.237
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