Protein Interactions That Regulate Cell Polarity

描述(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。极性是细胞的基本属性，对正常发育和成人生理都是必需的。例如，在发育过程中，细胞命运决定因素在细胞分裂过程中两极分化，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确定细胞的极性，必须解释细胞信号，并最终将其与相关细胞成分的分离相关联。 我们选择专注于一种在控制细胞极性方面发挥核心作用的蛋白质复合体。这个复合体包括PAR蛋白PAR-3和PAR-6，以及非典型蛋白激酶C(APKC)，定位于特定的细胞部位，随后被认为招募细胞极化机制的下游成分。我们选择关注这个进化上保守的复合体中的蛋白质，以便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。我们的大部分工作将集中在了解Rho GTPase家族信号分子是如何调节这些适配蛋白的定位、组装和/或活性的，最近被证明与PAR-6相互作用。我们还专注于阐明PDZ蛋白相互作用结构域如何介导复合体的组装以及与下游成分的相互作用。我们剩下的工作将致力于了解这些蛋白质随后如何激活细胞极性机制的组件。 我们将使用生化、生物物理和细胞生物学相结合的方法来研究PAR 复杂的函数。使用生化和生物物理方法，我们将检查PAR复合体组装并与细胞极性机制的信号分子和下游组件相互作用的物理基础。最后，我们将在果蝇上皮细胞和神经母细胞中测试这些相互作用在体内的重要性，这是两种细胞极性的模型。

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.