Biochemical and cellular functions of Karyopherins

核传递蛋白的生化和细胞功能

• 批准号: 10427212
• 负责人: Yuh Min Chook
• 金额: $ 43.42万
• 依托单位: UT SOUTHWESTERN MEDICAL CENTER
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-11 至 2026-05-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10427212
• 关键词: Address; Affect; Apoptosis; Base Sequence; Binding; Biochemical; Cell physiology; Consensus; Disease; Exportins; Health; Histone H2A; Histones; Human; Importins; Karyopherins; Laboratories; Malignant Neoplasms; Maps; Mediating; Molecular Chaperones; Mutation; Nuclear; Nuclear Export; Nuclear Import; Nucleosomes; Oncogenic; Proteins; RNA-Binding Proteins; Saccharomyces cerevisiae; Signal Transduction; Specificity; Structure; System; base; cancer cell; comparative; design; improved; inhibitor; mRNA Export; nucleocytoplasmic transport; prevent; response; small molecule inhibitor; transportin SR

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.

Chook实验室旨在了解核蛋白蛋白如何识别的机制 绑定合作伙伴和地图合作伙伴/货物库。我们旨在了解核质质 运输，其他核蛋白的功能，并发现它们如何组织和调节细胞功能 健康和疾病。 20个同源人和14 S. cerevisiae kaps介导了大多数核 运输。我们已经广泛研究了核蛋白核蛋白-β2。我们发现了PY-NLS 认识到该信号的物理组织，并设计了第一个核进口 抑制剂。 Karyopherin-β2和其他特征良好的导入蛋白，Importin-/β，Importin-5和 Transportin-SR具有不同的规格并结合了完全不同的NLS类型。但是，剩下的 importins：importin-4，importin-7，importin-8，importin-9和importin-11的研究不足很少 已知的货物。钙的稀缺性阻止了其比较生化/结构的定义 NLSS。我们的目的是发现新的Cargos和NLS类，以了解Importins，并绘制 他们控制的交通。我们表明，除了进口货物外，进口素还充当伴侣 防止RNA结合蛋白聚集或充当组蛋白伴侣，以防止组蛋白H2A-H2B 聚集并有助于核小体组装。我们将解决KAP2Chainone的机制 功能，以及在存在规范组蛋白的情况下如何进口和伴侣H2A-H2B 伴侣。在核出口研究中，我们为理解做出了重大贡献 CRM1如何绑定NES和小分子抑制剂，但是考虑到CRM1的问题还有更多问题 在许多细胞过程和疾病状态中的重要性。 CRM1抑制剂selinexor会导致细胞凋亡 癌细胞，但尚不清楚哪些碳是针对不同癌症的。大多数> 1000 含NES的CRM1货物尚不清楚。准确的NES预测可以帮助识别新的Cargos， 但是，在大多数螺旋中描述序列无处不在的序列 - 包含蛋白质使基于序列的NES预测效率低下。为了改善预测，我们是 开发基于结构和能量的NES预测指标。我们还将研究CRM1如何降解 对抑制剂的反应，了解CRM1的致癌E571K突变如何影响NES结合 CRM1介导的流量，并研究CRM1介导的mRNA导出。最后，我们将扩大研究 与多个固有无序和磷酸化段结合的导出MSN5 Cargos，因此是定义新的NES课程的绝佳系统。