The role of spatio-temporal nano-organization in regulating the specificity of JAK/STAT signaling

配体诱导的信号通过质膜中的特异性受体的传播是细胞在多细胞生物体中实现其复杂作用的关键过程。虽然这一过程是如何介导的不同受体类型的主要范例已经建立，分子和生物物理参数，控制信号激活的配体的特异性，是远远不够清楚。一个关键的挑战是理解所谓的信号特异性悖论，即有限的细胞内信号效应子可以控制无数的信号输出。这个跨学科和合作项目的总体目标是揭示JAK/STAT信号特异性的特异性如何通过质膜和内体中活化的干扰素受体（IFNR）复合物的纳米区室化来控制。IFNRs代表了研究这些机制复杂性的最佳范例之一，因为I型IFNAR和II型IFNGR都激活共同的STAT 1分子，但显示出不同的转录输出。Lamaze小组（P1）最近表明，IFNR内吞运输和质膜上基于脂质的纳米组织分别在I型和II型干扰素（IFN）激活JAK/STAT的选择性中发挥关键作用。Piehler小组（P2）已经建立了先进的成像技术，使用单分子定位成像技术监测IFNR组装和时空动力学。质膜纳米区室化成肌动蛋白和脂质为基础的域的作用将通过使用生物化学和遗传修饰进行探讨。具体来说，我们的目标是确定IFNGR定位到脂筏的具体功能，可能与特定的脂质和半乳糖凝集素的相互作用。我们将通过质谱法（P1）识别新的相互作用伙伴，这将通过功能表面微图案化（P2）在活细胞中进行验证。这些相互作用伙伴在IFNR信号传导中的作用将通过生物物理学（P2）和功能研究（P1）进一步阐明。基于从这些研究中获得的详细机制图片，我们将尝试系统地交换I型和II型IFN受体之间的功能模块，以验证它们在特定细胞环境中的功能相关性（P1）。

Ligand-induced signal propagation through specific receptors in the plasma membrane is a key process for the cell in order to fulfill its complex role within multicellular organisms. While principal paradigms of how this process is mediated by different receptor types have been established, the molecular and biophysical parameters, which control the specificity of signal activation by the ligand, are far from being clear. A key challenge is to understand the so-called paradox of signaling specificity where a limited set of intracellular signaling effectors can control myriads of signaling outputs. The overall aim of this interdisciplinary and collaborative project is to uncover how the specificity of JAK/STAT signaling specificity is controlled by the nano-compartmentalization of the activated interferon-receptor (IFNR) complexes at the plasma membrane and in endosomes. IFNRs represent one of the best paradigms to investigate the complexity of these mechanisms since both type I IFNAR and type II IFNGR activate a common STAT1 molecule but display a distinct transcriptional output. The Lamaze group (P1) has recently shown that IFNR endocytic trafficking and lipid-based nano-organization at the plasma membrane play a key role in the selectivity of JAK/STAT activation by type I and type II interferons (IFNs), respectively. The Piehler group (P2) has established advanced imaging techniques for monitoring IFNR assembly and spatiotemporal dynamics using single molecule localization imaging techniques. The role of plasma membrane nano-compartmentalization into actin and lipid-based domains will be explored by using biochemical and genetic modifications. Specifically, we aim to identify how specific features of IFNGR localization into lipid rafts, are probably related to specific lipid and galectin interactions. We will identify new interaction partners by mass spectrometry (P1), which will be validated in living cells by functional surface micropatterning (P2). The role of these interaction partners in IFNR signaling will be further elucidated by biophysical (P2) and functional studies (P1). Based on the detailed mechanistic picture obtained from these studies, we will attempt to systematically swap functional modules between the type I and type II IFN receptors in order to validate their functional relevance in a specific cellular context (P1).