Plant Protein Farnesyltransferase: Role in the Cell Cycle Control

小行星9604681 蛋白法尼基转移酶（FTase）介导的脂质附着（即，法呢基）部分与蛋白质的结合促进易位至质膜，从而激活信号蛋白如p21 ras。 因此，FTase在许多信号通路中发挥重要作用。 最近的研究表明，FTase在植物脱落酸信号转导和细胞周期调控中起着关键作用。 然而，参与这些植物信号事件的法尼基化蛋白尚未被鉴定。 在我们的初步研究中，拟南芥Ras样小GTP结合蛋白（RLP 1）被证明是法尼基化在体外，其全长cDNA测序。 这代表了第一个已知被法尼基化的植物信号蛋白，并为阿坝信号或细胞周期控制中的法尼基化蛋白提供了强有力的候选者。 在这个修改后的目标，我们将研究这种G蛋白在植物中的功能。 将进行两个具体实验。 1)将RLP 1与水母绿色荧光蛋白融合并在烟草BY-2细胞中表达，以证明RLP 1的体内法尼基化并确定其亚细胞定位。 2)将通过定点诱变产生显性负性和组成型活性的RLP 1突变体形式，并在BY-2细胞中表达，以直接评估其在植物信号传导途径如阿坝或促有丝分裂信号传导中的作用。 这项工作将提供重要的新的洞察法尼基化和法尼基化的蛋白质在信号转导中的作用。 这个项目将研究参与调节植物细胞分裂的信号过程。了解植物细胞分裂是如何调节的是一个重要的基本过程，在生物技术和农业的影响。杨博士发现，一种可能参与细胞分裂过程中信号传导的蛋白质被脂质修饰。脂质的附着和去除可能是信号传导过程中的重要步骤之一。该项目将提供蛋白质的脂质修饰与植物细胞分裂调控之间的相关性的详细信息。

9604681 Yang Protein farnesyltransferase (FTase)-mediated attachment of a lipid (i.e., farnesyl) moiety to proteins facilitates translocation to the plasma membrane and thus activation of signaling proteins such as p21ras. As a result, FTase plays an important role in many signaling pathways. Recent studies suggest that FTase plays a critical role in abscisic acid signaling and cell cycle control in plants. However, farnesylated proteins involved in these plant signaling events have not been identified. In our preliminary studies, an Arabidopsis Ras-like small GTP-binding protein (RLP1) was shown to be farnesylated in vitro, and its full-length cDNA was sequenced. This represents the first plant signaling protein known to be farnesylated and provides a strong candidate for a farnesylated protein in ABA signaling or cell cycle control. In this revised objective, we will investigate the function of this G-protein in plants. Two specific experiments will be conducted. 1) RLP1 will be fused to the jellyfish green fluorescence protein and expressed in tobacco BY-2 cells to demonstrate in vivo farnesylation of RLP1 and to determine its subcellular localization. 2) Dominant negative and constitutively active mutant forms of RLP1 will be created by site-directed mutagenesis and expressed in BY-2 cells to directly assess its role in plant signaling pathways such as ABA or mitogenic signaling. This work will provide significant new insight into the role of farnesylation and farnesylated proteins in signal transduction. This project will examine the a signal processes that are involved in regulating cell division in plant cells. Understanding how plant cell division is regulated is an important fundamental process with implications in biotechnology and agriculture. Dr. Yang has discovered that one protein that may be involved in signaling during cell division is modified with the attachment of a lipid. The attachment and removal of the lipid may be one of the essential steps in the signali ng process. This project will provide detailed information on the correlation between lipid modification of the protein and the regulation of plant cell division.