Cell polarity, asymmetric cell division and differentiation in plants.

项目摘要 从有限数量的祖细胞产生不同的后代是多细胞生物学的一个重大挑战。 有机体祖细胞不断更新自己，同时产生新的细胞类型;这个过程 需要不对称细胞分裂（ACD），这是干细胞的标志。ACD过程中的一个关键过程是细胞 祖细胞的极化。这项研究的长期目标是阐明设计原则， 控制植物ACD中的细胞极化和细胞命运分化。 植物气孔的形成和图案化需要精确控制的ACD。拟南芥气孔 系统提供了一个很好的平台来研究植物ACD的机制，因为这些部门是 刻板和高度可预测的，叶表皮暴露在空气中是很容易获得遗传 表征和细胞检查。PI鉴定出拟南芥中第一个内在极性蛋白BASL （打破气孔谱系的不对称性），通过其在等离子体中的高度极化分布来控制ACD 膜的然而，皮层BASL极性域如何定义以及细胞极性如何调节气孔 亚洲合作对话在很大程度上仍难以实现。拟议的研究将采用综合方法， 生物化学，先进的细胞生物学和蛋白质组学/磷酸蛋白质组学方法，以（1）了解如何囊泡 运输控制靶向膜递送以促进气孔ACD细胞的极化和（2） 确定极性驱动的，不对称分布的内体活性如何区分两个子细胞， 工厂ACD。 研究中的分子机制包括蛋白质极化，内膜运输， 磷脂信号传导，以及细胞极化中信号转导和内体功能之间的串扰 和不对称细胞分裂，所有这些都与人类干细胞活性的研究明显相关， 功能

PROJECT SUMMARY Generating diverse progenies from a limited number of progenitor cells is a significant challenge for multicellular organisms. The progenitor cells continuously renew themselves while generating new cell types; this process requires asymmetric cell divisions (ACD), a hallmark of stem cells. A key process during ACD is the cellular polarization of progenitor cells. The long-term goal of the research is to elucidate the design principles that govern cellular polarization and cell fate differentiation in plant ACD. The formation and patterning of stomata in plants require precisely controlled ACDs. The Arabidopsis stomata system provides an excellent platform to study the mechanisms for ACD in plants, because these divisions are stereotypic and highly predictable, and the leaf epidermis exposed in the air is readily accessible to genetic characterization and cellular examination. The PI identified the first intrinsic polarity protein in Arabidopsis, BASL (Break Asymmetry of the Stomatal Lineages), that controls ACD by its highly polarized distribution at the plasma membrane. However, how the cortical BASL polarity domain is defined and how cell polarity regulates stomatal ACD remain largely elusive. The proposed studies will apply a comprehensive approach combining genetics, biochemistry, advanced cell biology, and proteomic/phosphoproteomic methods to (1) understand how vesicular trafficking controls targeted membrane delivery to promote the polarization of stomatal ACD cells and (2) determine how polarity-driven, asymmetrically distributed endosomal activity differentiates two daughter cells in plant ACD. The molecular mechanisms under investigation involve protein polarization, endomembrane trafficking, phospholipid signaling, and crosstalk between signal transduction and endosomal function in cell polarization and asymmetric cell division, all of which are clearly related to the studies of human stem cell activity and function.