Regulation mechanisms of ABC transporters

项目总结 这项提议试图了解位于细胞膜中的蛋白质是如何作为守门人工作的 有选择地允许化合物进入或离开细胞。这样的网守被称为或ATP绑定 盒(ABC)转运体，因为它们使用ATP(三磷酸腺苷)水解的能量 通过细胞膜运输化合物。细菌ABC进口子对 生物体存活，控制从细菌中清除的营养物质的摄取速度 环境。对运输速度的控制防止了营养物质的过度积累 在低浓度时有益，但在高浓度时有潜在的毒性。而ABC的一个子集 蛋白质含有一个额外的“辅助”结构域，该结构域可以通过 关闭传输器，不清楚为什么某些传输器包含这些域名，而其他传输器则包含这些域名 不要这样做。然而，我们确实理解某些传输器在特定的情况下被关闭 化合物或蛋白质结合到这个辅助结构域上。其他附属域通过“感知”来调节 微环境的变化和相应的反应。为了破译这一监管机制， PI的实验室将生化和生物物理实验与结构生物学相结合， 了解这些附属结构域如何在运输调节中发挥作用，从而限制或 允许营养物质进入细胞。这项研究计划将定义分子机制 控制养分吸收，并使研究人员了解多种运输系统如何在 在生物体内维持细胞生存的协调一致。我们将检验我们的假设，即监管 通过感知辅助蛋白激活转运蛋白。拟议中的研究将破译 模型系统中复杂的调节电路有三个目标：(1)了解PepT SBP如何 在微环境中选择不同的底物(即营养物质、辅因子和多肽)；(2) 确定核心运输车的组装如何决定运输的选择性和效率(3) 揭示PepT转运蛋白如何通过激活一种 新的监管领域。这项研究计划已着手弥合在认识上的关键差距 所有细菌中存在的运输机制的基本原理。结果将产生深刻的见解 了解调控结构域如何调节所有生物体之间的运输，这对细胞生存至关重要。

PROJECT SUMMARY This proposal seeks to understand how proteins located in the cell membrane work as gatekeepers to selectively allow compounds into or out of the cell. Such gatekeepers are known as or ATP-binding cassette (ABC) transporters, because they use the energy of ATP (adenosine triphosphate) hydrolysis to transport compounds across the cell membrane. Bacterial ABC importers are essential for organism survival, controlling the rate of uptake for nutrients scavenged from the bacterium's environment. Control of the rate of transport precludes over-accumulation of a nutrient that is beneficial at low concentrations, but is potentially toxic at high concentrations. While a subset of ABC proteins contain an additional “accessory” domain that can regulate the uptake of compounds by shutting off the transporter, it is unclear why certain transporters contain these domains while others do not. However, we do understand that certain transporters are “turned off” when a specific compound or protein binds to this accessory domain. Other accessory domains regulate by “sensing” changes in the microenvironment and reacting accordingly. To decipher this mechanism of regulation, the PI's laboratory combines biochemical and biophysical experiments with structural biology to understand how these accessory domains play a role in transport regulation, which in restricts or allows nutrients to enter the cell. This research program will define the molecular mechanism that controls nutrient uptake and allow researchers to understand how multiple transport systems work in concert within an organism to maintain cell survival. We will test our hypothesis that regulation of transporter activation via a sensing accessory protein. The proposed research will decipher the complex circuitry of regulation in a model system in three Aims to: (1) understand how PepT SBPs select for different substrates within the microenvironment (i.e., nutrients, cofactors and peptides); (2) determine how the assembly of the core transporter dictates transport selectivity and efficiency (3) reveal how PepT transporters regulate the import of substrates into the cell through the activation of a novel regulatory domain. This research program has set out to close critical gaps in the understanding of the fundamentals of the transport mechanism present in all bacteria. The results will yield insights into how regulatory domains modulate transport across all organisms, crucial for cell viability.