The endoplasmic reticulum (ER) as a key regulator of metabolism

我们的实验室研究控制细胞内膜之间接触的蛋白质。这些触点传递各种信号，并控制许多细胞功能。内质网(ER)形成了最广为人知的细胞内联系。我们的研究计划旨在了解这些物质的功能。在这个提案中，我们研究了内质网接触如何通过线粒体-内质网接触(MERS)决定细胞新陈代谢和细胞能量输出。这一生命的关键结构由两个细胞器之间的脂类和钙离子流动控制。我们实验室正在进行的研究表明，这种流动是由传感器蛋白控制的。这些感应器的上游是决定接触部位蛋白质组成的Rab蛋白。这些GTP酶利用与一种称为GTP的高能化合物的可逆结合来丰富或去除Mercs中的传感器蛋白。我们的初步结果表明，Rab32介导的传感器蛋白对Mercs的定位对内质网衍生的氧化应激做出反应。根据我们的观察，我们假设内质网应激和RAB介导的Merc重塑共同决定细胞代谢。在NSERC的应用中，我们将检验这一假设，并通过引入酿酒酵母作为我们实验的新模型系统来调查这些功能的保守程度。我们的项目旨在回答几个关键问题。Rab GTP酶对常见的上游信号有反应吗？如果有，是哪一种？这些信号是如何控制RABS和传感器蛋白的？我们提出了以下具体目标：1.GTP酶如何响应内质网衍生的蛋白质折叠压力？我们将分析在ER蛋白折叠压力下RABS的活性是否发生变化。我们将测试这些变化是否依赖于RAB翻译后的修饰或与鸟嘌呤核苷酸交换因子(GEF)的相互作用。2.Merc膜如何将ER GTP酶活性传递给线粒体？我们将分析影响ER的GTP酶如何改变Merc的关键性质(蛋白质组、钙处理和脂体)并控制线粒体代谢。3.内质网代谢需求向线粒体的传递是否保守？我们将对酵母进行分析，以保存我们的观察结果，并筛选新的Mercs代谢调节剂。我希望这项提案将酵母和动物模型系统结合起来，建立一个基于ER相关GTP酶运输蛋白的代谢网络。我们NSERC资助的研究项目的继续对于保持我们实验室各级高素质人才(HQP)的一流培训和出版成功至关重要。

Our laboratory investigates proteins that control contacts between intracellular membranes. These contacts communicate a variety of signals and control many cellular functions. The endoplasmic reticulum (ER) forms the best-known intracellular contacts. Our research program aims to understand the functions of these. In this proposal, we investigate how ER contacts determine cellular metabolism and the cellular energy output via mitochondria-ER contacts (MERCs). This key structure for life is controlled by a flow of lipids and Ca2+ ions between the two organelles. Ongoing research from our lab shows this flow is controlled by sensor proteins. Upstream of these sensors are Rab proteins that determine the protein composition of the contact site. These GTPases use the reversible binding to a high energy compound called GTP to either enrich or remove sensor proteins from MERCs. Our preliminary results show that Rab32-mediated localization of sensor proteins to MERCs responds to ER-derived oxidative stress. From our observations, we hypothesize that ER stress and Rab-mediated MERC remodeling cooperate to determine cellular metabolism. In this NSERC application we will test this hypothesis and also investigate the extent of conservation of these functions by introducing the yeast S. cerevisiae as a new model system for our experiments. Our project aims to answer several key questions. Do Rab GTPases respond to a common upstream signal and if so which one? How do such signals control Rabs and the sensor proteins? We propose the following specific aims: 1. How do GTPases respond to ER-derived protein folding stress? We will analyze whether the activity of Rabs changes upon ER protein folding stress. We will test whether these changes depend on Rab post-translational modifications or interactions with guanine nucleotide exchange factors (GEFs). 2. How do MERC membranes transmit ER GTPase activity to mitochondria? We will analyze how ER-influencing GTPases change MERC key properties (proteome, Ca2+ handling and lipidome) and control mitochondria metabolism. 3. Is the transmission of ER metabolic needs to mitochondria conserved? We will analyze yeast for the conservation of our observations and to screen for novel metabolic regulators of MERCs. I expect this proposal to combine yeast and animal model systems to establish a metabolic network based on ER-associated GTPase trafficking proteins. The continuation of our NSERC-funded research program is essential to maintain the first-class training and publication success of high-quality personnel (HQP) of all levels in our lab.