Studies on the Protein-assisted Mechanism for Intracellular Membrane Contact Sites

这个项目将探索被称为细胞器的细胞室之间脂质运动的机制。最近，强有力的证据表明，大多数脂质运输都是在脂质运输蛋白的帮助下进行的，这种蛋白可以促进细胞器接触，即所谓的膜接触部位的形成。酵母中的氧固醇结合同源蛋白(OSH)是形成膜接触部位的脂类转运蛋白的一个例子，是细胞器间脂类交换的极好模型。由于细胞可以用来生产用于商业用途的化学品，了解脂质交换和修饰它的方法可以提高化学品的产量。该项目将为研究人员提供科学培训，重点从代表性不足的群体中招聘。项目概念和成果将被用于为少数族裔服务的高中暑期计划、课程的教育推广，以及为普通公众开发动手蛋白质工程活动。OSH蛋白最初被认为是运输类固醇，但最近被证明在信号脂类的运输中起着重要作用，如磷脂酰肌醇。这个项目结合了实验和计算技术，首先研究Osh蛋白的膜结合区，然后研究全长蛋白形成膜接触点的机制，以阐明膜接触点的形成和探测脂交换。Osh蛋白质的脂质包装传感器与模型膜(平面和曲面)的结合将使用增强采样模拟、中子衍射和高分辨率场循环核磁共振来探索。Osh4与膜相互作用的其他结构域将被研究，重点是这种蛋白质可能如何构象变化以促进膜接触部位。最终，将通过开发新的双膜结合计算工具以及场循环核磁共振和荧光技术来探索全长Osh4蛋白形成膜接触部位和脂质转移的机制。这项建议由分子和细胞生物科学部的细胞动力学和功能组以及分子生物物理学组共同资助。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This project will probe the mechanism of lipid movement between cellular compartments known as organelles. Recently, strong evidence indicates that most lipid transport occurs with the help of lipid transport proteins that can facilitate the formation of organelle contacts known as membrane contact sites. The oxysterol binding homologue (Osh) proteins of yeast are an example of lipid transport proteins that form membrane contact sites and serve as an excellent model for lipid exchange between organelles. Since cells can be used to produce chemicals for commercial use, understanding lipid exchange and ways to modify it could improve production of chemicals. This project will provide scientific training for researchers with focused recruitment from underrepresented groups. Project concepts and results will be used in educational outreach for minority-serving high school summer programs, courses, and developing hands-on protein engineering activities for the general public. Osh proteins were originally thought to transport sterols but have recently been shown to be important in the transport of signaling lipids, such as phosphatidylinositols. This project integrates experimental and computational techniques to elucidate membrane contact site formation and probe lipid exchange by first studying membrane-binding regions of Osh proteins and then the mechanism the full-length protein uses to form membrane contact sites. The binding of the lipid-packing sensor of Osh proteins to model membranes (planar and curved) will be probed using enhanced sampling simulations, neutron diffraction, and high-resolution field-cycling NMR. Other domains of Osh4 interacting with membranes will be studied with a focus on how this protein might conformationally change to facilitate membrane contact sites. Ultimately, the mechanism of the full-length Osh4 protein to form membrane contact sites and lipid transfer will be probed by developing new computational tools for dual-membrane binding and the use of field-cycling NMR and fluorescence techniques. This proposal is jointly funded by the Cellular Dynamics and Function cluster and Molecular Biophysics cluster in the Division of Molecular and Cellular Biosciences.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.