Plant Cell Cycle Regulation and Protein Ubiquitination

植物生长是因为细胞（更具体地说是分生组织中的细胞）分裂，然后这些新细胞的大小增加。因此，细胞分裂是植物生长的基础。由于细胞分裂在生物学中的关键作用，人们对植物中调控细胞分裂周期的基因进行了深入的研究。我在这个领域的研究旨在了解细胞分裂、植物生长及其相关过程的分子和生化机制。这项研究的发现有可能促进植物生长（例如种子大小）和增加生物量。真核生物的细胞周期是由一类称为细胞周期蛋白依赖性激酶（CDKs）的酶控制的，CDK抑制剂可以调节细胞周期蛋白依赖性激酶。此前，我们从拟南芥（植物分子生物学研究的模式物种）中发现了首个植物CDK抑制剂基因ICKs。它们为理解调控植物细胞周期的分子机制提供了很好的工具。我们对植物细胞周期调控家族的功能和调控的理解做出了重大贡献。尽管取得了进展，但许多重要问题仍未得到解答。我们将进一步研究ICK在植物中的功能、蛋白稳定性、CDK抑制机制和核定位的生物学意义。此外，我们将研究一种新的蛋白质泛素化（一种蛋白质修饰）途径，并确定其在植物生长发育中的作用。本研究将保持我们现有的对植物CDK抑制剂家族的研究，并在蛋白质修饰的新途径上有新的发现。

Plants grow because cells (more specifically cells in the meristems) divide and these new cells then increase in size. Therefore, cell division is fundamental for plant growth. Due to the pivotal biological role of cell division, there has been intensive research activities aimed at understanding genes that regulate the cell division cycle in plants. My research in this area aims to understand the molecular and biochemical mechanisms regulating cell division, plant growth and related processes. The discoveries from this research have the potential to enhance plant growth (e.g. seed size) and increase biomass. The cell cycle in eukaryotes is controlled by a class of enzymes called cyclin-dependent kinases (CDKs), which can be regulated by CDK inhibitors. Previously, we discovered the first plant CDK inhibitor genes called ICKs from the plant Arabidopsis thaliana (a model species for plant molecular biology studies). They provide an excellent tool to understand the molecular mechanisms regulating the plant cell cycle. We have contributed significantly to the understanding of the functions and regulation of this family of plant cell cycle regulators. Despite the progress, many important questions remain unanswered. We will further study and focus on ICK functions in plants, protein stability, mechanisms of CDK inhibition and biological significance of nuclear localization. In addition, we will on a novel protein ubiquitination (one type of protein modification) pathway and determine its roles in plant growth and development. The proposed research will maintain our exiting strong research on a family of plant CDK inhibitors, and make new discoveries in a novel pathway of protein modification.