Molecular Determinants and Functional Consequences of Pannexin Mechanosensitivity

Pannexins是一种形成通道的糖蛋白，可以在质膜上传导强大的宏观电流，允许大小达1 kDa的有机和无机阳离子和阴离子的流动，包括ATP。在已知的三种亚型(Panx1-3)中，Panx1长期以来一直被认为是主要的功能亚型，并与生理过程有关，包括星形胶质细胞钙波的传播和学习记忆背后的突触可塑性形式。尽管在识别Panx1的生理功能方面取得了进展，但我们对促进其激活的机制的了解还很初级。对Panx1门控机制的基础知识的缺乏是进一步了解这些通道执行的生物学功能的障碍。有趣的是，已知Panx1通道对机械刺激有反应。然而，Panx1机械敏感性的机制尚不清楚。过去的研究表明，机械敏感通道与细胞骨架成分，如肌动蛋白和微管的偶联，是通道介导的机械刺激向细胞反应转导的主旨。值得注意的是，Panx1的羧基末端已被证明与丝状肌动蛋白(F-肌动蛋白)相互作用。然而，这种相互作用的功能后果尚未确定。结合分子、生化、电生理和超分辨率成像方法，HQP将在我的实验室开展工作，试图确定Panx1机械敏感性的分子机制，以及Panx1机械敏感性对细胞运动和细胞对机械刺激的适应的贡献。鉴于人们对识别允许细胞感知和响应环境中机械特性变化的机制的认识和兴趣日益增加，拟议的实验将为Panx1对机械生物学的贡献提供重要的见解。

Pannexins are channel forming glycoproteins that conduct robust macroscopic currents across the plasma membrane, allowing flux of organic and inorganic cations and anions of up to 1 kDa in size, including ATP. Amongst the three known isoforms (Panx1-3) Panx1 has long been viewed as the predominant functional subtype and has been linked to physiological processes including astrocytic calcium wave propagation and forms of synaptic plasticity underlying learning and memory. Despite progress in identifying physiological functions contributed by Panx1, our understanding of mechanisms that promote their activation is rudimentary. The absence of fundamental knowledge regarding Panx1 gating mechanisms is a barrier to furthering our understanding of the biological functions executed by these channels. Intriguingly, Panx1 channels are known to respond to mechanical stimulus. However, the mechanisms underlying Panx1 mechanosensitivity are not known. Past studies suggest that coupling of mechanosensitive channels to cytoskeletal components, such as actin and microtubules, is a leitmotif for channel-mediated transduction of mechanical stimuli into cellular responses. Of note, the carboxyl terminus of Panx1 has been shown to interact with filamentous actin (F-actin). However, the functional consequence of this interaction has not been determined. Using a combination of molecular, biochemical, electrophysiological and super-resolution imaging approaches, work to be undertaken by HQPs in my lab will seek to identify the molecular mechanisms responsible for Panx1 mechanosensitivity and the contribution of Panx1 mechanosensitivity to cell motility and cellular adaptations to mechanical stimuli. Given increasing recognition and interest in identifying mechanisms that allow cells to sense and respond to changes in the mechanical properties in their environment, the proposed experiments will provide important insight regarding the contribution of Panx1 to mechanobiology.