Protein Interactions That Regulate Cell Polarity

描述（由申请人提供）：这项工作的长期目标是了解细胞极性的结构和生化基础。极性是细胞的一个基本特性，是正常发育和成人生理所必需的。例如，在发育过程中，细胞命运决定因素在分裂细胞中被极化，作为产生细胞类型多样性的机制。为了在空间和时间上精确地建立细胞极性，必须解释细胞信号并最终将其与相关细胞组分的分离相结合。 我们选择专注于在控制细胞极性中起核心作用的蛋白质复合物。该复合物包括PAR蛋白Par-3和Par-6以及非典型蛋白激酶C（aPKC），定位于特定的细胞位点，随后被认为募集细胞极化机制的下游组分。我们选择专注于这个进化上保守的复合物中的蛋白质，以了解它们的相互作用，它们是如何定位的，以及它们如何作为开关来传递控制细胞极性的信息。我们的大部分努力将是针对了解Rho GTdR家族的信号分子，最近已被证明与Par-6相互作用，调节这些衔接蛋白的定位，组装和/或活性。我们还专注于阐明PDZ蛋白相互作用结构域如何介导复合物的组装以及与下游组分的相互作用。我们剩下的努力将致力于了解这些蛋白质如何随后激活细胞极性机制的组成部分。 我们将使用生物化学、生物物理学和细胞生物学相结合的方法来研究Par 复杂函数使用生物化学和生物物理学的方法，我们将研究的物理基础，Par复杂的组装和相互作用的信号分子和下游组件的细胞极性机制。最后，我们将测试这些相互作用在果蝇上皮细胞和神经母细胞，细胞极性的两个模型在体内的重要性。

DESCRIPTION (provided by applicant): The long-term goal of this work is to understand the structural and biochemical basis of cell polarity. Polarity is a fundamental property of cells that is required for proper development as well as adult physiology. For example, during development, cell fate determinants are polarized in dividing cells as a mechanism for generating cell type diversity. For spatially and temporally precise establishment of cell polarity to occur, cellular signals must be interpreted and ultimately coupled to the segregation of relevant cellular components. We have chosen to focus on a protein complex that plays a central role in controlling cell polarity. This complex, which includes the PAR proteins Par-3 and Par-6, and the atypical protein kinase C (aPKC), localizes to specific cellular sites and subsequently is thought to recruit downstream components of the cell polarization machinery. We have chosen to focus on the proteins in this evolutionarily conserved complex in order to understand their interactions, how they are localized, and how they act as switches to transmit the information that controls cell polarity. Much of our effort will be directed towards understanding how the Rho GTPase family of signaling molecules, which have recently been shown to interact with Par-6, regulates localization, assembly, and/or activity of these adapter proteins. We are also focusing on elucidating how the PDZ protein-interaction domain mediates assembly of the complex and interactions with downstream components. The remainder of our effort will be directed at understanding how these proteins subsequently activate components of the cell polarity machinery. We will use a combined biochemical, biophysical and cell biological approach to investigate Par complex function. Using biochemical and biophysical methods, we will examine the physical basis by which the Par complex assembles and interacts with signaling molecules and downstream components of the cell polarity machinery. Finally, we will test the in vivo importance of these interactions in Drosophila epithelial and neuroblast cells, two models for cell polarity.