Nucleocytoplasmic transport: a target for cellular control

描述（由申请人提供）：核和细胞质区室之间交换的唯一介质是核孔复合物（NPC），由称为核孔蛋白或NUP的蛋白质组成。核质转运由可溶性转运因子（大多数属于称为核转运蛋白或Kaps的蛋白质的相关家族）驱动，其携带其同源货物穿过NPC。这种运输在多个层面上受到调节，包括核转运蛋白的货物识别以及与NPC的相互作用。NPC还通过影响核结构和作为各种核过程的控制点在基因表达中起关键调节作用。主要的病理细胞过程与改变的核质转运有关，许多病毒靶向核质转运途径的组分以篡夺它。因此，核孔蛋白和转运因子是药物治疗的关键潜在靶点。我们将专注于两个关键的监管领域的核质运输，结构信息是最有可能导致这些监管过程的基本机制的见解。首先，我们将研究卡普如何识别他们的货物。Kaps的重叠特异性赋予细胞选择性控制数千种货物运输的能力，并为药理学干预提供了丰富的潜在靶点来源。PSI生物学将提供与其货物结合的Kaps的晶体结构，这将补充生物化学和生物信息学方法，以揭示货物识别的序列和结构要求。其次，我们将以高分辨率绘制NPC的篮子区域，这是一系列令人困惑的核过程的关键控制点。这些过程是介导的篮子蛋白之间的相互作用，然而，分配这些不同的功能域的篮子蛋白已被证明在很大程度上是不成功的，主要是因为很少有人知道它的结构组织和其组件的相互依赖性。因此，篮组件的原子结构和它们的相互作用PSI生物学将与我们的互补生物物理，形态学和蛋白质组学数据的选择与NPC相关的亚复合物，以获得一个高分辨率的地图的核篮的背景下的NPC和核周边。一旦建立，这个地图将被用来指导解剖和扰动的各个组成部分，阐明篮子的结构组织和机制，它执行其各种功能之间的关系。

DESCRIPTION (provided by applicant): The sole mediators of exchange between the nuclear and cytoplasmic compartments are nuclear pore complexes (NPCs), comprised of proteins termed nucleoporins or Nups. Nucleocytoplasmic transport is driven by soluble transport factors (most belonging to a related family of proteins termed karyopherins or Kaps) that carry their cognate cargos across the NPC. This transport is regulated at multiple levels, including cargo recognition by karyopherins and interactions with the NPC. The NPC also plays a key regulatory role in gene expression by influencing nuclear architecture and acting as a point of control for various nuclear processes. Major pathological cellular processes are associated with altered nucleocytoplasmic transport, and many viruses target components of the nucleocytoplasmic transport pathway to usurp it. Hence, nucleoporins and transport factors are key potential targets for drug therapy. We will focus on two of the key regulatory areas of nucleocytoplasmic transport, where structural information is most likely to lead to fundamental mechanistic insights into these regulatory processes. First, we will investigate how Kaps recognize their cargos. The overlapping specificity of Kaps endows cells with the ability to selectively control the transport of thousands of cargos and provides a rich source of potential targets for pharmacological intervention. PSI Biology will provide crystal structures of Kaps bound to their cargos, which will complement biochemical and bioinformatics approaches to reveal both the sequence and structure requirements for cargo recognition. Second, we will map at high resolution the basket region of the NPC, a critical point of control for a bewildering array of nuclear processes. These processes are mediated by the interplay of interactions among the basket proteins; however, assigning these varied functions to domains of the basket proteins has proven largely unsuccessful, primarily because little is known about its structural organization and the interdependence of its components. The atomic structures of basket components and their interactors from PSI Biology will therefore be integrated with our complementary biophysical, morphological, and proteomic data on selected subcomplexes associated with the NPC to obtain a high resolution map of the nuclear basket in the context of the NPC and nuclear periphery. Once established, this map will be used to guide the dissection and perturbation of individual components, to elucidate the relationship between the structural organization of the basket and the mechanisms by which it executes its various functions.