Structures of full-length FGFR cancer fusions and disease mutants

当细胞需要分裂和复制时(例如，在胚胎发育、生长或伤口愈合期间)，细胞会收到生长因子发出的信号。这些信号通过受体酪氨酸激酶(RTK)从细胞外部传递到内部，在细胞外，生长因子结合在细胞内，RTK是位于细胞膜内并跨越细胞膜的蛋白质。虽然部分RTK的结构已知，但完整(全长)RTK的高分辨率结构尚未确定，因此我们对不同结构域如何相互作用控制信号还不完全了解。在这个项目中，我们将使用先进的原子分辨方法，如冷冻电子显微镜和核磁共振光谱，确定全长成纤维细胞生长因子受体(FGFRs)的结构。FGFR和FGRF的改变形式导致了几种类型的人类癌症和一些发育障碍，是控制胚胎发育、伤口愈合和新血管生长(血管生成)等过程的原型RTK。FGFRs通常通过成纤维细胞生长因子(FGFs)与其细胞外(细胞外)区域的结合而激活，但在一些癌症和发育疾病中，FGFRs可以改变，即使没有FGFRs的结合也能永久激活。了解FGFRs不同结构域(如细胞外和细胞内部分)之间的结构联系对于我们了解FGFRs和其他RTK如何正常发挥作用至关重要--例如，它们如何在静止状态下被自动抑制，然后被激活。尤其是在一种与癌症相关的FGFRs变体中，FGFR3基因的一部分与另一种蛋白质TACC3的部分基因融合，产生一种高度激活的杂交蛋白，并定位于细胞的不同部分。这些所谓的FGFR3-TACC3融合导致了某些类型的胶质母细胞瘤(侵袭性脑瘤)和一些膀胱癌。在结构水平上了解超激活是如何发生的，将提高我们选择性靶向这些融合蛋白的能力，以更好地治疗它们所负责的癌症。我们还预计，这些具有异常活性的FGFR的疾病相关变体可能会与各种不同的蛋白质伙伴形成新的细胞内复合体。为了充分了解突变如何影响功能，我们还必须确定能够促进和调节信号转导的结合伙伴。为此，我们研究的另一个方面将是在实验室培养的癌细胞中使用交联质谱(XL-MS)来识别这些新的伙伴，并找出这些相互作用是如何促进疾病过程的。通过提高我们对(正常和疾病改变的)FGFR结构和细胞相互作用的知识，我们的目标是更好地了解为什么FGFR靶向药物分子在某些疾病环境中有效，而在另一些疾病环境中效果不佳，以及我们如何才能开发更有效的药物分子。总之，我们的项目旨在解决以下问题：-通过解决完整的FGFRs及其与癌症相关的改变形式(例如FGFR-TACC融合)的结构，我们能否更好地了解细胞外信号(如生长因子结合)是如何转化为激活的FGFRs产生的不同细胞内反应的？-FGFRs在正常细胞和癌细胞中形成哪些功能复合体，它们为我们提供了什么关于潜在的新的治疗靶向策略的信息？

Cells receive signals from growth factors when they need to divide and replicate (e.g., during embryonic development, growth, or wound healing). These signals are transmitted from the outside of the cell, where the growth factor binds, to the inside, by receptor tyrosine kinases (RTKs) - proteins that sit within and span across the cell membrane. Although the structures for parts of RTKs are known, high resolution structures of whole (full-length) RTKs have yet to be determined, so our understanding of how the different domains interact to control signalling is incomplete.In this project, we will determine structures of full-length fibroblast growth factor receptors (FGFRs), using cutting-edge atomic-resolution methods such as cryo-electron microscopy and nuclear magnetic resonance spectroscopy. FGFRs, and altered forms of FGRFs that are responsible for several types of human cancers as well as for some developmental disorders, are archetypal RTKs that control processes such as embryonic development, wound healing, and growth of new blood vessels (angiogenesis). FGFRs are normally activated by binding of fibroblast growth factors (FGFs) to their extracellular (outside of the cell) regions, but in some cancers and developmental diseases they can become altered so that they are permanently active even without FGF binding.Understanding the structural connections between the different domains of FGFRs (e.g. extracellular and intracellular parts) is essential if we are to understand how FGFRs and other RTKs function normally - for example, how they are auto-inhibited in the resting state but then become activated. This is particularly the case for a cancer-associated variant of FGFRs whereby part of the FGFR3 gene becomes fused with part of the gene from another protein, TACC3, to generate a hybrid protein that is hyperactivated and also localises to different parts of the cell. These so-called FGFR3-TACC3 fusions are responsible for certain types of glioblastomas (aggressive brain tumours) and some bladder cancers. Understanding at a structural level how the hyperactivation occurs will improve our ability to selectively target these fusion proteins to better treat those cancers for which they are responsible.We also anticipate that these disease-associated variants of FGFRs with aberrant activity are likely to form novel intracellular complexes with a variety of different protein partners. To fully understand how mutations may affect function we must also identify binding partners that can facilitate and regulate signal transduction. To this end another aspect of our research will be to use cross-linking mass spectrometry (XL-MS) in lab-grown cancer cells to identify these new partners and find out how those interactions contribute to the disease process.By improving our knowledge of (normal and disease-altered) FGFR structures and cellular interactions, we aim to understand better why FGFR-targeted drug molecules are effective in some disease settings and less so in others, and how we can then develop more efficacious drug molecules. In summary, our project aims to address the following questions:- Through solving the structures of complete FGFRs and their cancer-associated altered forms (e.g. FGFR-TACC fusions), can we better understand how extracellular signals (such as growth factor binding) are translated into the different intracellular responses generated from activated FGFRs?- What functional complexes do FGFRs form in normal and cancer cells, and what do they tell us about potential new therapeutic drug targeting strategies?