Analysis of a putative PSI receptor domain in plant inositol transporters

植物肌醇转运蛋白中假定的 PSI 受体结构域分析

• 批准号: 169441960
• 负责人: Professor Dr. Norbert Sauer
• 金额: --
• 依托单位: Department Biologie
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2013-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/169441960?language=en
• 关键词: Analysis; putative; PSI; receptor; domain

Plasma membrane-localized H+-inositol symporters from plants and animals share a common structure of 12 transmembrane helices and a large extracellular loop between the predicted helices IX and X. This extracellular loop is absent from the otherwise closely related H+-inositol symporters from bacteria and fungi and from H+- inositol symporters of the plant tonoplast. Based on extensive analyses in the yeast and Xenopus expression systems we could show that removal of this loop domain increased the rate of inositol uptake, and on the basis of in silico structural and phylogenetic analyses we could demonstrate that this domain represents a novel PSI (= plexin, semaphorin, integrin) domain. PSI domains perform protein/protein interactions and were so far found almost exclusively in the extracellular regions of single-transmembrane-domain (type I) receptors from animals, but neither in transport proteins nor in plants. In summary, our data suggest that plant and animal H+-inositol symporters share receptor functions or regulatory binding sites for extracellular protein partners. The aim of the proposed work is the identification of proteins interacting with the loop domains of the Arabidopsis AtINT2 and AtINT4 proteins and the elucidation of the underlying physiological process and regulatory pathways.

来自植物和动物的质膜定位的H+-肌醇共转运体共享12个跨膜螺旋和预测的螺旋IX和X之间的大的细胞外环的共同结构。这种细胞外环不存在于细菌和真菌的H+-肌醇共转运体和植物液泡膜的H+-肌醇共转运体中。基于在酵母和非洲爪蟾表达系统中的广泛分析，我们可以表明去除该环结构域增加了肌醇摄取的速率，并且基于计算机结构和系统发育分析，我们可以证明该结构域代表了一种新的PSI（=丛蛋白、信号蛋白、整联蛋白）结构域。PSI结构域执行蛋白质/蛋白质相互作用，并且迄今为止几乎仅在动物的单跨膜结构域（I型）受体的细胞外区域中发现，但既不在转运蛋白中也不在植物中发现。总之，我们的数据表明，植物和动物的H+-肌醇共转运体共享受体功能或调节结合位点的胞外蛋白伴侣。拟开展的工作的目的是确定与拟南芥AtINT 2和AtINT 4蛋白质的环域相互作用的蛋白质，并阐明潜在的生理过程和调控途径。