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Mechanoelectrical transduction is mediated by the opening of different types of force-sensitive ion channels, including Piezo1/2 and the TREK/TRAAK K 2P channels. Piezo1 curves the membrane locally into an inverted dome that reversibly flattens in response to force application. Moreover, Piezo1 forms numerous preferential interactions with various membrane lipids, including cholesterol. Whether this structural architecture influences the functionality of neighboring membrane proteins is unknown. Here, we show that Piezo1/2 increase TREK/TRAAK current amplitude, slow down activation/deactivation, and remove inactivation upon mechanical stimulation. These findings are consistent with a mechanism whereby Piezo1/2 cause a local depletion of membrane cholesterol associated with a prestress of TREK/TRAAK channels. This regulation occurs in mouse fibroblasts between endogenous Piezo1 and TREK-1/2, both channel types acting in concert to delay wound healing. In conclusion, we demonstrate a community effect between different structural and functional classes of mechanosensitive ion channels. [Display omitted] • TREK/TRAAK mechanical activation is upregulated and kinetics are delayed by Piezo1/2 • Piezo1 opening is required for enhancing TREK-1 current amplitude • Local depletion of membrane cholesterol contributes to the upregulation of TREK-1 • Piezo1 upregulates TREK-1/2 in mouse fibroblasts causing a delay in wound healing Glogowska et al. show that Piezo1/2 enhance the mechanical activation of K 2P channels, slow down activation/deactivation, and remove inactivation. Piezo1/2 cause a prestress of TREK/TRAAK attributable to a local depletion of membrane cholesterol. A native regulation between Piezo1 and TREK-1/2 occurs in mouse gingival fibroblasts. [ABSTRACT FROM AUTHOR]

Integrin-mediated cell adhesion regulates a vast number of biological processes including migration, survival and proliferation of cells. It is therefore not surprising that defects in integrin function are often rate-limiting for development and profoundly affect the progression of several diseases. The functions of integrins are mediated through the recruitment of cytoplasmic plaque proteins. One of these is integrin-linked kinase, which connects integrins to the actin cytoskeleton and transduces signals through integrins to the extracellular matrix and from integrins to various subcellular compartments. [Copyright &y& Elsevier]

The development of calibrated Förster resonance energy transfer (FRET)-based tension sensors has allowed the first analyses of mechanical processes with piconewton (pN) sensitivity in cells. Here, we introduce the working principle of this emerging microscopy method and discuss how it has been utilized to obtain quantitative insights into the mechanisms of intracellular force transduction in cell–matrix adhesions, cell–cell junctions, and at the cell cortex. These examples demonstrate that genetically encoded tension sensors are powerful tools to unravel force transduction mechanisms, but also indicate current limitations. We propose that further technical improvements are needed to develop a truly molecular understanding of mechanobiological processes in cells and tissues. [ABSTRACT FROM AUTHOR]

Integrin-linked kinase (ILK) localizes to focal adhesions (FAs) where it regulates cell spreading, migration, and growth factor receptor signaling. Previous reports showed that overexpressed ILK in which Val386 and Thr387 were substituted with glycine residues (ILK-VT/GG) could neither interact with paxillin nor localize to FA in cells expressing endogenous wild-type ILK, implying that paxillin binding to ILK is required for its localization to FAs. Here, we show that introducing this mutation into the germ line of mice (ILK-VT/GG) caused vasculogenesis defects, resulting in a general developmental delay and death at around embryonic day 12.5. Fibroblasts isolated from ILKVT/ GG mice contained mutant ILK in FAs, showed normal adhesion to and spreading on extracellular matrix substrates but displayed impaired migration. Biochemical analysis revealed that VT/GG substitutions decreased ILK protein stability leading to decreased ILK levels and reduced binding to paxillin and α-parvin. Because paxillin depletion did not affect ILK localization to FAs, the embryonic lethality and the in vitro migration defects are likely due to the reduced levels of ILK-VT/GG and diminished binding to parvins. [ABSTRACT FROM AUTHOR]

Abstract: Induction of tenascin-C mRNA by cyclic strain in fibroblasts depends on RhoA and Rho dependent kinase (ROCK). Here we show that integrin-linked kinase (ILK) is required upstream of this pathway. In ILK-deficient fibroblasts, RhoA was not activated and tenascin-C mRNA remained low after cyclic strain; tenascin-C expression was unaffected by ROCK inhibition. In ILK wild-type but not ILK −/− fibroblasts, cyclic strain-induced reorganization of actin stress fibers and focal adhesions, as well as nuclear translocation of MAL, a transcriptional co-activator that links actin assembly to gene expression. These findings support a role for RhoA in ILK-mediated mechanotransduction. Rescue of ILK −/− fibroblasts by expression of wild-type ILK restored these responses to cyclic strain. Mechanosensation is not entirely abolished in ILK −/− fibroblasts, since cyclic strain activated Erk-1/2 and PKB/Akt, and induced c-fos mRNA in these cells. Conversely, lysophosphatidic acid stimulated RhoA and induced both c-fos and tenascin-C mRNA in ILK −/− cells. Thus, the signaling pathways controlling tenascin-C expression are functional in the absence of ILK, but are not triggered by cyclic strain. Our results indicate that ILK is selectively required for the induction of specific genes by mechanical stimulation via RhoA-mediated pathways. [Copyright &y& Elsevier]