Polar Lipid Trafficking Between the Endoplasmic Reticulum and the Chloroplast

内质网和叶绿体之间的极性脂质运输

• 批准号: 0453858
• 负责人: Christoph Benning
• 金额: $ 45万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2008-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0453858&HistoricalAwards=false
• 关键词: Polar; Lipid; Trafficking; Between; Endoplasmic

Cells and intracellular compartments (organelles) are enclosed by biological membranes. Polar lipids are the building blocks of cell membranes and lipid transfer between different membranes is essential for the growth and maintenance of all cells. The isolation of new genetic mutants of Arabidopsis with deficiencies in the transfer of polar lipids from the endoplasmic reticulum (ER) to the photosynthetic membranes in chloroplasts has led to the identification of three proteins (TGD1-3) with striking similarity to the permease- (TGD1), substrate-binding- (TGD2), and ATP-binding proteins (TDG3) of predicted bacterial ABC transporters. It is hypothesized that the TGD1-3 proteins are components of a phosphatidic acid (PA) translocator in the chloroplast envelopes. Loss of function leads to the accumulation of PA and the diversion of ER-derived glycerolipids into triacylglycerols. In addition, a processive galactosyltransferase at the outer chloroplast envelope is activated in the mutants, which causes the accumulation of oligogalactolipids. This project focuses on the functional analysis of the three TGD proteins and their role in lipid transfer at the chloroplast envelopes. Specific aims are to (1) determine the subcellular localization of the TGD1-3 proteins, (2) determine the physical interaction between TGD1, TGD2 and TGD3, (3) determine the lipid substrate for the proposed complex and (4) determine the ATPase activity for TGD3. The project involves the participation of postdoctoral researchers, graduate students as well as undergraduate students and offers training opportunities for persons with different skill levels. Because the employed approaches are ranging from Arabidopsis genetics, to plant biochemistry and plant cell biology, a broad training experience is provided to all trainees. In addition, postdoctoral researchers will gain valuable experience in the supervision of students.

细胞和胞内室（细胞器）被生物膜包裹。极性脂质是细胞膜的基石，不同膜之间的脂质转移对所有细胞的生长和维持至关重要。从拟南芥中分离出极性脂质从内质网（ER）向叶绿体光合膜转移缺陷的新基因突变体，鉴定出三种蛋白质（TGD1-3），它们与预测的细菌ABC转运蛋白的渗透酶- (TGD1)、底物结合蛋白（TGD2）和atp结合蛋白（TDG3）惊人地相似。据推测，TGD1-3蛋白是叶绿体包膜中磷脂酸（PA）转运子的组分。功能丧失导致PA的积累和er衍生的甘油脂转化为三酰基甘油。此外，在突变体中，叶绿体外包膜上的一种半乳糖转移酶被激活，导致低聚半乳糖脂的积累。本项目重点研究了三种TGD蛋白的功能分析及其在叶绿体膜脂质转移中的作用。具体目的是：(1)确定TGD1-3蛋白的亚细胞定位，(2)确定TGD1、TGD2和TGD3之间的物理相互作用，(3)确定所提出复合物的脂质底物，(4)确定TGD3的atp酶活性。该项目涉及博士后研究人员、研究生和本科生，并为不同技能水平的人员提供培训机会。由于采用的方法从拟南芥遗传学到植物生物化学和植物细胞生物学，因此为所有学员提供了广泛的培训经验。此外，博士后研究人员将在指导学生方面获得宝贵的经验。