Negative and positive feedback in cell signaling

项目总结 在过去的半个世纪里，科学家们对细胞如何检测荷尔蒙、营养素 以及其他化学线索。通常，这些信号由G蛋白偶联受体检测，并被 由化学第二信使转导的，如cAMP或钙。我们的实验室长期以来一直专注于 反馈调节因子的鉴定和特性，最显著的是RGS蛋白。鉴于受体 激活G蛋白，RGS蛋白通过加速GTP水解失活G蛋白。 在接下来的五年里，我们的实验室将专注于小说第二部的鉴定和表征 信使及其在信号协调的两个方面的作用。第一个重点是信号协调，通过 一种信息素gpr和另一种检测营养物质的gpr。第二个是信息素gpcr是如何 通过自噬和分子构件的循环，调节营养的可获得性。 这一新的倡议建立在我们的发现基础上，即G蛋白调节生理，并受生理调节 细胞内pH和2-羟基支链氨基酸的变化。这些代谢物是第二种 分别是葡萄糖限制和渗透胁迫的信使，并分享触发G蛋白的能力 磷酸化和失活。 我们的总体方法是系统地确定(从药理上)刺激细胞的效果， 删除(基因上的)信号通路组件，测量(核磁共振和质谱学)变化 细胞蛋白质和代谢物，(生化)重组G蛋白和效应器蛋白的活性， 以及解决(X射线和核磁共振)与其生理靶标结合的第二信使的结构。 如果成功，我们的研究计划将导致识别新的第二信使，他们的 作用机制，以及它们在细胞中的功能后果。我们的调查将需要 实施多个研究平台和战略，从而大大受益于灵活性和 由Mira计划提供的稳定性。

PROJECT SUMMARY Over the past half century scientists have learned much about how cells detect hormones, nutrients and other chemical cues. Typically, these signals are detected by a G protein-coupled receptor and are transduced by a chemical second messenger, such as cAMP or calcium. Our lab has long focused on the identification and characterization of feedback regulators, most notably RGS proteins. Whereas receptors activate G proteins, RGS proteins inactivate G proteins through accelerated GTP hydrolysis. In the next five years our lab will focus on the identification and characterization of novel second messengers and their roles in two aspects of signal coordination. The first is focused on signal coordination by a pheromone GPCR and by another GPCR that detects nutrients. The second is how the pheromone GPCR regulates nutrient availability, through autophagy and the recycling of molecular building blocks. This new initiative builds on our discovery that G proteins regulate, and are regulated by, physiological changes in intracellular pH and of 2-hydroxy branched chain amino acids. These metabolites are second messengers of glucose limitation and osmotic stress, respectively, and share the ability to trigger G protein phosphorylation and inactivation. Our overall approach is to systematically determine the effects of stimulating (pharmacologically) the cell, deleting (genetically) signaling pathway components, measuring (NMR and mass spectrometry) changes in cellular proteins and metabolites, reconstituting (biochemically) the activity of G proteins and effector kinases, and solving (x-ray and NMR) the structures of second messengers bound to their physiological targets. If successful, our research program will lead to the identification of novel second messengers, their mechanism of action, and their functional consequences in the cell. Our investigations will require the implementation of multiple research platforms and strategies, and thus benefit greatly from the flexibility and stability provided by the MIRA program.