The Regulation and Function of the Ubiquitin-Sensing Kinase TNK1

项目摘要/摘要 激酶信号的改变是许多最具破坏性的人类疾病的基础，包括 退行性疾病、自身免疫和癌症。因此，并不令人惊讶的是，激酶是第二大 靶向药物靶点组(G蛋白偶联受体旁边)。然而，尽管它们在 疾病，只有大约8%的激酶是FDA批准的药物的靶点，大约四分之一的 人类亲属组中的634个蛋白激酶仍被认为研究不足，剩下100多个蛋白激酶 未被开发为潜在的治疗靶点，没有明确的生物学功能。这项提案将重点放在 TnK1，非受体酪氨酸激酶ACK激酶家族中知之甚少的成员 (NRTK)。我们最近发布的数据(NAT.通讯。2021)揭开了监管的第一个机制 以及该激酶上不寻常的泛素联合(UBA)结构域的存在。关键差距 与此相关的机制以及目前尚不清楚的TNK1的细胞功能在本文中作了阐述 求婚。我们的长期目标是发现细胞生长和存活的机制 针对疾病的治疗靶点。这项提案的总体目标是建立第一个 这一未被研究的激酶的详细机制和功能。中心假设是 TNK1 UBA结构域与泛素丰富的多泛素化蛋白簇的结合 缩合物作为诱导邻近的一种形式来寡聚和激活TNK1(目标1)。我们也 假设14-3-3与TNK1的磷酸化Ser502相互作用抑制TNK1的寡聚 并隐藏UBA结构域，从而将TNK1与处于非活性状态的泛素隔离 (目标2)。最后，我们假设TNK1感觉到多聚泛素积累到磷酸化。 促进富含泛素缩合物的溶酶体降解(吞噬)的底物(目标 3)。这项提议意义重大，因为它填补了我们对TNK1理解的一个基本空白，提供了一种 了解突变如何在疾病中激活TNK1的框架，并将为药理学提供信息 利用我们最近开发的TNK1抑制剂在疾病中靶向TNK1的策略。 这项提议是创新的，因为它解决了一种新的激酶激活机制 直接与多泛素相互作用，从而建立富含泛素的缩合物作为组织 TNK1/激酶信号转导平台。

PROJECT SUMMARY/ABSTRACT Alterations in kinase signaling underlie many of the most devastating human diseases, including degenerative disease, autoimmunity and cancer. Thus, not surprisingly, kinases are the second most targeted group of drug targets (next to G-protein coupled receptors). Yet despite their importance in disease, only about 8% of kinases are targets of FDA approved drugs and roughly a quarter of the 634 kinases in the human kinome is still considered ‘understudied’, leaving over 100 kinases untapped as potential therapeutic targets and without clear biological functions. This proposal focuses on TNK1, a poorly understood member of the ACK kinase family of non-receptor tyrosine kinases (NRTKs). Our recently published data (Nat. Comm. 2021) uncovered the first mechanism of regulation and the unusual presence of a ubiquitin-association (UBA) domain on this kinase. Critical gaps relating to this mechanism and the still unknown cellular function of TNK1 are addressed in this proposal. Our long-term goal is to discover mechanisms of cell growth and survival that can be therapeutically targeted in disease. The overall objectives of this proposal are to establish the first detailed mechanism and function of this understudied kinase. The central hypothesis is that the binding of the TNK1 UBA domain to clusters of poly-ubiquitinated proteins at ubiquitin-rich condensates acts as a form of induced proximity to oligomerize and activate TNK1 (aim 1). We also hypothesize that the interaction of 14-3-3 with phospho-Ser502 of TNK1 inhibits TNK1 oligomerization and conceals the UBA domain, thereby sequestering TNK1 away from ubiquitin in an inactive state (aim 2). Finally, we posit that TNK1 senses the accumulation of poly-ubiquitin to phosphorylate substrates that promote the lysosomal degradation (aggrephagy) of ubiquitin-rich condensates (aim 3). The proposal is significant because it fills a basic gap in our understanding of TNK1, provides a framework to understand how mutations activate TNK1 in disease, and will inform pharmacological strategies that take advantage of our recently developed TNK1 inhibitor to target TNK1 in disease. The proposal is innovative because it addresses a novel mechanism of kinase activation through direct interaction with poly-ubiquitin, thereby establishing ubiquitin-rich condensates as organizing platforms for TNK1/kinase signaling.