A family of novel G-protein coupled receptor-type proteins involved in cell wall integrity sensing

植物细胞壁是一个复杂的碳水化合物聚合物网络，控制着整个植物的形态发生。隔离墙的组成部分代表了几个行业的基本组成部分，包括食品、纺织和造纸行业。此外，细胞壁聚合物纤维素是地球上含量最丰富的生物聚合物，估计将成为葡萄糖衍生乙醇形式的生物燃料的主要前体。尽管如此，关于纤维素和其他细胞壁聚合物是如何产生的，以及这种产生是如何控制的，人们知之甚少。通过有针对性的反向遗传学筛选，我们获得了几个与初生壁纤维素产生相关的候选基因。其中一个基因对应于一个假定的七跨膜蛋白(7TM)，但没有已知的生物学功能。奇怪的是，这个蛋白质家族中的几个成员似乎在细胞壁完整性和糖分感知方面发挥了作用。初步结果表明，这7个TM中至少有一个是G蛋白偶联受体(GPCR)。因此，我们认为细胞壁结构的状态可以通过GPCR介导的信号机制进行监测。我们建议对7TM蛋白家族进行功能鉴定，并确定与该信号框架相关的其他成分。这项拟议的研究应该会在理解细胞壁和细胞内部之间的联系方面取得重大进展，并可能导致为各种工业目的操纵细胞壁聚合物的生产的能力。

The plant cell wall is a complex network of carbohydrate-based polymers that controls overall plant morphogenesis. The constituents of the wall present essential components for several industries, including the food-, textile- and paper industries. In addition, the cell wall polymer cellulose, representing the most abundant biopolymer on earth, is estimated to become the main precursor for biofuels in the form of glucose-derived ethanol. Despite this, very little is known about how cellulose, and other cell wall polymers are produced, and how such production is controlled.Through a targeted reverse genetics screen we obtained several candidate genes associated with primary wall cellulose production. One of the genes corresponds to a putative seven transmembrane (7TM) protein with no known biological function. Curiously, several members of this protein family appear to have a role in cell wall integrity-, and sugar sensing. Preliminary results suggest that at least one of the 7TMs is a G-protein coupled receptor (GPCR). We therefore believe that the status of the cell wall architecture may be monitored via a GPCR mediated signaling scheme. We propose to functionally characterize the 7TM protein family, and to identify additional components associated with this signaling framework. The proposed research should lead to major advances in understanding the communication between the cell wall and the cell’s interior, and may result in the ability to manipulate the production of cell wall polymers for various industrial purposes.