Calcium regulatory proteins in plants and yeasts; an NMR approach

植物和酵母中的钙调节蛋白；

• 批准号: RGPIN-2015-05977
• 负责人: Vogel, Hans(Harm)
• 金额: $ 2.77万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=687069
• 关键词: Calcium; regulatory; proteins; plants; yeasts

Calcium plays an important role as a secondary messenger in all eukaryotic cells. An increase in the cytosolic Ca2+ level can act like a trigger by binding to regulatory calcium-binding proteins, such as calmodulin (CaM). Collectively upon binding Ca2+ these 'calcium-sensor' proteins can redirect the physiological status of a cell. In plants the cytosolic Ca2+ level increases in response to various abiotic and biotic stresses such as cold, drought, salt, wounding or the presence of plant pathogens. As such Ca2+ is an important mediator of the plant stress response. Recent genome sequencing efforts have shown that all plants contain a large diversity of calcium-sensor proteins such as distinct CaM's, numerous CaM-like proteins as well as a variety of protein kinases and other systems that possess their own integrated CaM-like protein domains. For example, plants (and protozoa) contain a unique class of calcium binding protein kinases (commonly known as the CDPK's and CCaMK's) that are not found in other organisms. My research group has been interested in mapping out the molecular details of the calcium-sensor proteins and protein domains that participate in the plant stress response. The main experimental technique that we rely upon in this research program is Nuclear Magnetic Resonance (NMR) spectroscopy, which allows us to obtain detailed structural and dynamic information about these proteins and their complexes in their natural solution state. In addition we make use of various other biophysical tools to study the kinetics and energetics of the protein-calcium and protein-protein interactions. To date, we have determined the structures of the CaM-like domains of various plant protein kinases, as well as studied the properties of plant CaMs and their complexes with various enzymes and transmembrane calcium pumps. In the near future we want to study three selected CaM-like proteins that are directly involved in the plant stress response. Moreover, we plan to study how calcium-CaM can inhibit cyclic-nucleotide gated channels, that allow Ca2+ influx in the plant cells, by binding to a regulatory cytoplasmic domain of these channels. In addition, we will focus our attention on plant (and related yeast) fimbrins, a group of proteins that play an important role in plant growth. These proteins have been highly conserved during evolution and they are made up two calcium-binding motifs as well as four actin-binding CH-domains. Finally we plan to study a transport protein that is embedded in the membranes that surround the mitochondria. This protein specifically transports ATP-Mg2+ into the mitochondrial interior and it is regulated by Ca2+ through a unique CaM-like structure, that resides on top of the transmembrane channel. The knowledge gained through these projects may help in the future to improve the drought or salt-resistance of important crops or can help us develop new herbicides in a rational manner.**

钙离子作为第二信使在所有真核细胞中起着重要的作用。细胞质Ca 2+水平的增加可以通过与调节性钙结合蛋白（如钙调蛋白（CaM））结合而起到触发作用。在结合Ca 2+后，这些“钙传感器”蛋白可以共同改变细胞的生理状态。在植物中，胞质Ca 2+水平响应于各种非生物和生物胁迫（如寒冷、干旱、盐、创伤或植物病原体的存在）而增加。因此，Ca 2+是植物胁迫反应的重要介质。最近的基因组测序工作表明，所有植物都含有大量多样性的钙传感器蛋白，如不同的CaM，许多CaM样蛋白以及各种蛋白激酶和其他系统，拥有自己的整合CaM样蛋白结构域。例如，植物（和原生动物）含有一类独特的钙结合蛋白激酶（通常称为CDPK和CCaMK），这些激酶在其他生物体中没有发现。我的研究小组一直有兴趣绘制出参与植物胁迫反应的钙传感器蛋白和蛋白质结构域的分子细节。我们在这项研究计划中依赖的主要实验技术是核磁共振（NMR）光谱，它使我们能够获得有关这些蛋白质及其复合物在自然溶液状态下的详细结构和动力学信息。此外，我们利用各种其他生物物理工具来研究蛋白质-钙和蛋白质-蛋白质相互作用的动力学和能量学。到目前为止，我们已经确定了各种植物蛋白激酶的钙调素样结构域的结构，以及研究植物钙调素及其与各种酶和跨膜钙泵的复合物的性质。在不久的将来，我们希望研究三个选定的钙调素样蛋白，直接参与植物胁迫反应。此外，我们计划研究如何钙钙调素可以抑制环核苷酸门控通道，使Ca 2+流入植物细胞，通过结合到这些通道的调节胞质结构域。此外，我们将把我们的注意力集中在植物（和相关的酵母）fimbrins，一组在植物生长中发挥重要作用的蛋白质。这些蛋白在进化过程中高度保守，它们由两个钙结合基序和四个肌动蛋白结合CH结构域组成。最后，我们计划研究一种嵌入线粒体周围膜中的转运蛋白。该蛋白特异性地将ATP-Mg 2+转运到线粒体内部，并且其通过位于跨膜通道顶部的独特的CaM样结构由Ca 2+调节。通过这些项目获得的知识可能有助于在未来提高重要作物的抗旱性或抗盐性，或者可以帮助我们以合理的方式开发新的除草剂。