Biochemical and cellular functions of Karyopherins

Chook实验室的目标是了解核转运蛋白识别 结合伙伴和映射伙伴/货物库。我们的目标是了解核质 运输，其他karyopherin功能，并发现他们如何组织和调节细胞功能， 健康和疾病。20例同源人和14例S.酿酒酵母Kaps介导大多数核 运输我们对Karyopherin-β2进行了广泛的研究。我们发现PY-NLS 认识到，这一信号的物理组织特征，并设计了第一个核进口 抑制剂.核转运蛋白-β2和其他充分表征的输入蛋白，输入蛋白-β 2/β，输入蛋白-5和 转运蛋白-SR具有不同的特异性并结合完全不同的NLS类型。但剩下的 Importin：Importin-4，Importin-7，Importin-8，Importin-9和Importin-11，研究不足， 已知货物货物的稀缺性阻碍了它们的比较生物化学/结构定义 NLS。我们的目标是发现新的货物和NLS类研究不足的进口和映射 交通控制。我们发现，除了进口货物，进口也作为伴侣， 防止RNA结合蛋白聚集或作为组蛋白伴侣防止组蛋白H2 A-H2 B 聚集并协助核小体组装。我们将讨论Kap-2分子伴侣的机制 功能，以及Kap 114如何在典型组蛋白存在下导入和伴侣蛋白H2 A-H2 B 监护人在研究核出口方面，我们对了解 CRM 1如何结合NES和小分子抑制剂，但CRM 1的 在许多细胞过程和疾病状态中的重要性。CRM 1抑制剂Selinexor导致细胞凋亡 癌细胞，但目前还不知道哪些货物是针对不同的癌症。大多数>1000 含有NES的CRM 1货物未知。准确的内斯预测可以帮助识别新的货物， 但不同的内斯序列和模糊的共识，描述了在大多数螺旋中普遍存在的序列， 含有蛋白质的蛋白质使得基于序列的内斯预测效率低下。为了改善预测，我们 开发基于结构和能量的内斯预测器。我们还将研究CRM 1是如何在 对抑制剂的反应，了解CRM 1的致癌E571 K突变如何影响NES结合 和CRM 1介导的交通，并研究CRM 1介导的mRNA输出。最后，我们将扩大我们的研究 输出蛋白Msn 5，其结合多个细胞的内在无序和磷酸化片段， 货物，因此一个很好的系统来定义一个新的内斯类。

The Chook Laboratory aims to understand mechanisms of how Karyopherin- proteins recognize binding partners and map partner/cargo repertoires. We aim to understand nuclear-cytoplasmic transport, other karyopherin functions, and discover how they organize and regulate cellular functions, in health and in disease. 20 homologous human and 14 S. cerevisiae Kaps mediate the majority of nuclear transport. We have studied the importin Karyopherin-β2 extensively. We discovered the PY-NLS that it recognizes, characterized the physical organization of this signal and designed the first nuclear import inhibitor. Karyopherin-β2 and other well-characterized importins, Importin-/β, Importin-5 and Transportin-SR, have distinct specificities and bind entirely different NLS types. However, the remaining importins: Importin-4, Importin-7, Importin-8, Importin-9 and Importin-11, are under-studied with few known cargos. Scarcity of cargos has prevented comparative biochemical/structural definition of their NLSs. We aim to discover new cargos and classes of NLSs for understudied importins and map the traffic they control. We showed that in addition to importing cargos, importins also act as chaperones to prevent aggregation of RNA-binding proteins or act as histone chaperone to prevent histone H2A-H2B aggregation and assist in nucleosome assembly. We will address the mechanism of Kap2 chaperone functions, and how Kap114 imports and chaperones H2A-H2B in the presence of canonical histone chaperones. In the study of nuclear export, we have contributed significantly to the understanding of how CRM1 binds NESs and small molecule inhibitors, but there are many more questions given CRM1’s importance in many cellular processes and disease states. CRM1 inhibitor Selinexor causes apoptosis of cancer cells, but it is not known which cargos are targeted in different cancers. Most of the >1000 NES-containing CRM1 cargos are not known. Accurate NES prediction could help identify new cargos, but diverse NES sequences and vague consensus that describes sequences ubiquitous in most helix- containing proteins make sequence-based NES prediction inefficient. To improve prediction, we are developing a structure- and energy-based NES predictor. We will also study how CRM1 is degraded in response to inhibitors, understand how the oncogenic E571K mutation of CRM1 affects NES-binding and CRM1-mediated traffic, and study CRM1-mediated mRNA export. Finally, we will expand our study to the exportin Msn5, which binds intrinsically disordered and phosphorylated segments of multiple cargos, hence an excellent system to define a new NES class.