Biogenesis of beta-barrel proteins of the outer membranes of endosymbiotic organelles

内生共生细胞器、线粒体和质体的外膜构成了这些细胞器与其他细胞室之间的沟通平台。因此，这些膜的蛋白质组在进化过程中被采用，以满足从溶质和大分子交换到脂转移和信号转导的强加要求。绝大多数细胞器蛋白在细胞核中编码，并在胞质核糖体上合成。一组独特的这种细胞器蛋白质是那些具有β-桶结构的蛋白质，它们存在于两个细胞器的外膜中。这种OM蛋白从细胞质到靶膜的传递必须受到严格的调控，特别是在植物细胞中，两个细胞器必须平行供应，同时保持靶向性。定义这种特异性的靶向因素尚不清楚。我们将在酵母和植物细胞中鉴定这些因子，并将剖析它们在一般靶向蛋白质和将β-桶蛋白特定地输送到正确的细胞器中的功能。

The outer membranes (OM) of the endosymbiotically derived organelles mitochondria and plastids constitute the communication platform between these organelles and the other cell compartments. Consequentially, the proteomes of these membranes were adopted during evolution to fulfill the imposed requirements ranging from exchange of solutes and macromolecules to lipid transfer and signal transduction. The vast majority of organeller proteins are encoded in the nucleus and synthesized on cytosolic ribosomes. A unique group of such organellar proteins are those with beta-barrel architecture that are found in the outer membranes of both organelles. The delivery of such OM proteins from the cytosol to their target membrane has to be tightly regulated especially in plant cells where the two organelles have to be supplied in parallel while keeping targeting specificity. The targeting factors that define this specificity are not yet known. We will identify such factors in yeast and plant cells, and will dissect their function in targeting of proteins in general and for the specific delivery of beta-barrel proteins to the correct organelle.