Sianati Setareh, Schroeter Lioba, Richardson Jessica, Tay Andy, Lamandé Shireen R, Poole Kate
EMBL Australia Node in Single Molecule Science and Cellular and Systems Physiology, Faculty of Medicine, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.
Murdoch Children's Research Institute and Department of Paediatrics, University of Melbourne, Parkville, VIC, Australia.
Front Bioeng Biotechnol. 2021 Jan 18;8:608951. doi: 10.3389/fbioe.2020.608951. eCollection 2020.
Ion channels activated by mechanical inputs are important force sensing molecules in a wide array of mammalian cells and tissues. The transient receptor potential channel, TRPV4, is a polymodal, nonselective cation channel that can be activated by mechanical inputs but only if stimuli are applied directly at the interface between cells and their substrate, making this molecule a context-dependent force sensor. However, it remains unclear how TRPV4 is activated by mechanical inputs at the cell-substrate interface, which cell intrinsic and cell extrinsic parameters might modulate the mechanical activation of the channel and how mechanical activation differs from TRPV4 gating in response to other stimuli. Here we investigated the impact of substrate mechanics and cytoskeletal components on mechanically evoked TRPV4 currents and addressed how point mutations associated with TRPV4 phosphorylation and arthropathy influence mechanical activation of the channel. Our findings reveal distinct regulatory modulation of TRPV4 from the mechanically activated ion channel PIEZO1, suggesting the mechanosensitivity of these two channels is tuned in response to different parameters. Moreover, our data demonstrate that the effect of point mutations in TRPV4 on channel activation are profoundly dependent on the gating stimulus.
由机械输入激活的离子通道是多种哺乳动物细胞和组织中重要的力传感分子。瞬时受体电位通道TRPV4是一种多模态、非选择性阳离子通道，它可以被机械输入激活，但前提是刺激必须直接施加在细胞与其底物的界面处，这使得该分子成为一种依赖于环境的力传感器。然而，目前尚不清楚TRPV4在细胞-底物界面是如何被机械输入激活的，哪些细胞内在和细胞外在参数可能调节该通道的机械激活，以及机械激活与TRPV4对其他刺激的门控有何不同。在这里，我们研究了底物力学和细胞骨架成分对机械诱发的TRPV4电流的影响，并探讨了与TRPV4磷酸化和关节病相关的点突变如何影响该通道的机械激活。我们的研究结果揭示了TRPV4与机械激活离子通道PIEZO1不同的调节机制，表明这两种通道的机械敏感性是根据不同参数进行调节的。此外，我们的数据表明，TRPV4中的点突变对通道激活的影响在很大程度上取决于门控刺激。
