Multicomponent mechanochemical regulation of actin filament end dynamics

摘要 细胞肌动蛋白动力学在许多关键过程中是必不可少的，如细胞迁移、伤口愈合、细胞增殖、细胞凋亡、细胞增殖、细胞凋亡 分裂和内吞作用。生理肌动蛋白动力学是由蛋白质之间复杂的相互作用引起的， 影响新肌动蛋白结构组装或现有肌动蛋白分解的机制 结构.在过去的几十年里，大量调节细胞中肌动蛋白动力学的蛋白质已经被发现。 识别并单独表征。然而，我们仍然没有完全了解这些蛋白质是如何工作的 在多蛋白质生态系统中，它们是如何产生无法简单预测的紧急行为的 添加他们已知的个人活动。在过去的几年里，我发现了几个这样的 多元活动。我发现，肌动蛋白生长的增强剂（EAT）和阻断剂（加帽蛋白） 可以同时结合肌动蛋白丝上的同一位点，在此过程中启动它们自己的动态交换 在灯丝末端。我还完成了第一个直接的显微镜演示， 观察到环化酶相关蛋白（CAP）加速肌动蛋白丝的尖端解聚 和cofilin。在接下来的五年里，我们的目标是揭示多组分生化信号和 机械信号在单个肌动蛋白丝的尺度上被整合。我们将建立在我们开创性的 通过研究我们已经鉴定的其他蛋白质，我们发现了一些新的发现，这些蛋白质要么直接结合细丝末端，要么通过 其他末端结合蛋白。我们也将探讨机械力如何改变肌动蛋白的生化相互作用 与肌动蛋白丝结合的蛋白质。为了做到这一点，我们将采用一种独特的组合微流体辅助 （mf-TIRF）和多光谱单分子成像，这是我在过去几年中开创的。我们将 联合收割机将生物化学和生物物理实验与数学建模相结合。我的愿景是一个更好的 理解肌动蛋白动力学的分子机制将为开发新的 治疗人类疾病，如肌萎缩侧索硬化症（ALS），转移性癌症，神经系统疾病， (e.g.阿尔茨海默病和帕金森病）和发育障碍（例如肢体畸形）， 是由肌动蛋白动力学异常引起的。

ABSTRACT Cellular actin dynamics are essential in a number of key processes such as cell migration, wound healing, cell division and endocytosis. Physiological actin dynamics arises from a complex interplay between protein machineries that influence either the assembly of new actin structures or the disassembly of existing actin structures. Over the last few decades, a plethora of proteins regulating actin dynamics in cells have been identified and individually characterized. However, we still do not fully understand how these proteins work together in multiprotein ecosystems and how they give rise to emergent behavior that cannot be predicted simply by adding their known individual activities. Over the last few years, I have discovered several such multicomponent activities. I showed that an enhancer (formin) and a blocker (capping protein) of actin growth can simultaneously bind the same site on an actin filament, in the process initiating their own dynamic exchanges at filament ends. I also accomplished the first direct microscopic demonstration of a long-predicted but never observed acceleration of pointed-end depolymerization of actin filaments by cyclase-associated protein (CAP) and cofilin. Over the next five years, our goal is to uncover how multicomponent biochemical signals and mechanical signals get integrated at the scale of individual actin filaments. We will build on our ground-breaking discoveries by investigating other proteins that we have identified, which either directly bind filament ends or via other end-binding proteins. We will also investigate how mechanical forces alter biochemical interactions of actin binding proteins with actin filaments. To do this, we will employ a unique combination of microfluidics-assisted (mf-TIRF) and multispectral single molecule imaging that I have pioneered over the last few years. We will combine biochemical and biophysical experiments with mathematical modelling. My vision is that a better understanding of molecular mechanisms underlying actin dynamics will pave the way for development of new therapies to combat human ailments like Amyotrophic Lateral Sclerosis (ALS), metastatic cancer, neurological (e.g. Alzheimer's disease and Parkinson's diseases) and developmental disorders (e.g. limb deformities) that are caused due to abnormalities related to actin dynamics.