Functional characterization of two families of lipid droplet-associated proteins

两个脂滴相关蛋白家族的功能表征

• 批准号: 463059383
• 负责人: Professor Dr. Till Ischebeck
• 金额: --
• 依托单位: Arbeitsgruppe Plant Biochemistry and Biotechnology
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/463059383?language=en
• 关键词: Functional; characterization; two; families; lipid

Lipid droplets (LDs, also referred to as oil bodies or oleosomes) are subcellular structures that consist of proteins attached to or embedded in a phospholipid monolayer surrounding a hydrophobic core of mostly triacylglycerol. In plants, LDs occur not only in seeds and pollen but also in vegetative tissues, where they accumulate under stress. Studies in recent years also underlined important functions of LDs in abiotic and biotic stress responses. Previously only few protein families were known that are associated with lipid droplets but we could increase this number in the last years. Now, we aim to understand the subcellular and physiological function of these proteins including two families of proteins from Arabidopsis:SEED LIPID DROPLET PROTEIN 1 and 2 (SLDP1/2) and their binding partner LIPID DROPLET PLASMA MEMBRANE ANCHOR (LIPA) are proteins of previously unknown function that form a complex needed for the association of LDs with the plasma membrane (PM). We now want to study this complex further to show that SLDP1, SLDP2 and LIPA colocalize at LD and PM subdomains that form contact sites and do so in a co-dependent manner. We also want to study the importance of these contact sites under stress and if they play a role in membrane homeostasis. In addition, we want to identify further proteins associated with this complex. One potential interaction partner of SLDP1 was identified in a yeast-2-hybrid screen. This protein, SYNAPTOTAGMIN1, is associated with the PM and could act as a lipid transfer protein. It is furthermore involved in freezing stress tolerance. We want to find out if this protein is also associated with this complex and contributes to its function.We additionally want to study the LD-associated LIPID DROPLET METHYL TRANSFERASEs 1/2 (LIME1/2) and their function in plant metabolism and stress physiology. These proteins are annotated as N-methyltransferases and to be involved in secondary metabolism, but has so far not been studied in any detail. We detected these proteins not only in seedlings but also drought-stressed leaves. We want to identify the substrate and product of the reaction(s) catalyzed by this putative enzymes and the metabolic pathway they are involved in. Furthermore, we want to study the potential role of these enzymes in abiotic and biotic stress. With this project, we aim to broaden the knowledge on LDs in vegetative tissues.

脂滴(LDS，也称为油体或油小体)是一种亚细胞结构，由附着在磷脂单分子层上或嵌入其中的蛋白质组成，周围是主要是三酰甘油的疏水核心。在植物中，LDS不仅存在于种子和花粉中，还存在于营养组织中，在胁迫下积累在营养组织中。近年来的研究也强调了LDS在非生物和生物胁迫反应中的重要作用。以前只有几个已知的蛋白质家族与脂滴相关，但我们可以在过去几年增加这个数字。现在，我们的目标是了解这些蛋白的亚细胞和生理功能，包括来自拟南芥的两个蛋白家族：种子脂滴蛋白1和2(SLDP1/2)及其结合伙伴脂滴质膜锚(LIPA)，它们是功能未知的蛋白质，形成LDS与质膜(PM)结合所需的复合体。我们现在想进一步研究这个复合体，以表明SLDP1、SLDP2和LIPA共定位于形成接触位点的LD和PM亚域，并且以一种相互依赖的方式进行。我们还想研究这些接触部位在压力下的重要性，以及它们是否在膜内稳态中发挥作用。此外，我们还想进一步鉴定与该复合体相关的蛋白质。在酵母-2-杂交筛选中发现了SLDP1的一个潜在的相互作用伙伴。这种名为SYNAPTOTAGMIN1的蛋白质与PM有关，可以作为一种脂转移蛋白。此外，它还参与了冰冻胁迫的耐受性。我们还想研究LD相关的脂滴甲基转移酶1/2(LIME1/2)及其在植物新陈代谢和逆境生理中的功能。这些蛋白质被注释为N-甲基转移酶，并参与次生代谢，但到目前为止还没有任何详细的研究。我们不仅在幼苗中检测到这些蛋白质，而且在干旱胁迫下的叶片中也检测到了这些蛋白质。我们想要确定这种假定的酶催化的反应(S)的底物和产物以及它们所参与的代谢途径。此外，我们还想研究这些酶在非生物和生物胁迫中的潜在作用。通过这个项目，我们的目标是扩大关于营养组织中LDS的知识。