Novel functions of nuclear transport factors in cellular homeostasis

核转运因子参与真核细胞生理的各个方面。它们的作用范围从细胞生长到缩放、衰老和死亡。近年来的研究表明，核转运因子具有与RNA稳态和应激反应有关的新功能。为了支持这一模型，我们的团队证明了importin-a1与polyA-RNA结合。我们进一步发现所有进口蛋白a亚家族都与细胞质胁迫颗粒有关。应激颗粒包含多种蛋白质和rna。作为无膜的隔室，它们通过相分离组装。我们的实验室还建立了核转运因子和积聚受损RNA的细胞质颗粒之间的联系。这些独特的隔室不是应力颗粒。迄今为止，明确的实验证据表明核转运因子是通过相分离形成的细胞区室的重要调节因子。具体来说，核转运因子已经成为一个多层质量控制网络的支柱，该网络可以仔细检查细胞质中的RNA颗粒。其潜在的分子机制尚不清楚。我们的研究计划将解决这些核心的生物学问题。为此，我们建立了三个独立的体外和体内模型系统，它们越来越复杂。短期目标。我们将描述与蛋白质和RNA稳态相关的核转运因子的新生物学功能。长期目标。我们的研究计划将(i)定义由核转运因子驱动的蛋白质和RNA质量控制网络，（ii）剖析该网络调节最终决定细胞命运的生物过程的机制。假设。根据我们正在进行的研究，我们提出(1)核转运因子控制颗粒沉积；(2)核转运因子调节细胞质内RNA稳态。具体的目标。我们将在无细胞、细胞和有机体模型系统中测试我们的假设。具体而言，我们将：(1)定义核输运因子在应力颗粒组装、动力学、溶解和成纤化中的作用；(2)细胞质RNA损伤颗粒特征。的影响。基于我们最近获得的结果，我们的研究计划采取了一个新颖而令人兴奋的方向，探索核转运因子与细胞质RNA颗粒相关的意想不到的和不明确的功能。我们将把重点放在基本未知的生物学机制上。因此，我们的研究将确定核转运因子对调节细胞稳态的复杂质量控制系统的贡献。这些重要的生物过程与所有真核细胞有关。我们产生的见解将有助于定义促进细胞稳态的基本原理。我们将通过使用最先进的方法和仪器进行严格的多学科研究来实现这一目标。

Nuclear transport factors participate in different aspects of eukaryotic cell physiology. Their contributions range from cell growth to scaling, aging and death. Recent studies suggest new functions for nuclear transport factors that are related to RNA homeostasis and the stress response. In support of this model, our group demonstrated that importin-a1 binds polyA-RNA. We further showed that all importin-a sub-families associate with cytoplasmic stress granules. Stress granules contain a diverse set of proteins and RNAs. As membraneless compartments, they assemble through phase separation. Our laboratory also established links between nuclear transport factors and cytoplasmic granules that accumulate damaged RNA. These unique compartments are not stress granules. To date, clear experimental evidence shows that nuclear transport factors are essential regulators of cell compartments that form by phase separation. Specifically, nuclear transport factors have emerged as pillars of a multi-layered quality control network that scrutinizes RNA granules in the cytoplasm. The underlying molecular mechanisms are poorly understood. Our research program will address these central biological questions. To this end, we have established three independent in vitro and in vivo model systems of increasing complexity. SHORT-TERM OBJECTIVES. We will characterize novel biological functions of nuclear transport factors that are linked to protein and RNA homeostasis. LONG-TERM GOALS. Our research program will (i) define the protein and RNA quality control network that is driven by nuclear transport factors, and (ii) dissect the mechanisms through which this network modulates biological processes that ultimately determine cell fate. HYPOTHESES. Based on our ongoing studies, we propose that (1) nuclear transport factors control granulostasis; (2) nuclear transport factors regulate RNA homeostasis in the cytoplasm. SPECIFIC AIMS. We will test our hypotheses in cell-free, cellular and organismal model systems. In particular, we will: (1) Define the role of nuclear transport factors for stress granule assembly, dynamics, dissolution and fibrillization; (2) Characterize cytoplasmic RNA damage granules. IMPACT. Based on results we recently obtained, our research program takes a novel and exciting direction that explores the unexpected and ill-defined functions of nuclear transport factors as they relate to cytoplasmic RNA granules. We will focus on the underlying biological mechanisms that are largely unknown. Thus, our research will identify the contributions of nuclear transport factors to a complex quality control system that regulates cellular homeostasis. These important biological processes are relevant to all eukaryotic cells. The insights generated by us will help define basic principles that promote cellular homeostasis. We will achieve this through rigorous and multidisciplinary research that uses state-of-the-art methods and instrumentation.