BACKGROUND PLCγ enzymes are key nodes in cellular signal transduction and their mutated and rare variants have been recently implicated in development of a range of diseases with unmet need including cancer, complex immune disorders, inflammation and neurodegenerative diseases. However, molecular nature of activation and the impact and dysregulation mechanisms by mutations, remain unclear; both are critically dependent on comprehensive characterization of the intact PLCγ enzymes. METHODS For structural studies we applied cryo-EM, cross-linking mass spectrometry and hydrogen-deuterium exchange mass spectrometry. In parallel, we compiled mutations linked to main pathologies, established their distribution and assessed their impact in cells and in vitro. FINDINGS We define structure of a complex containing an intact, autoinhibited PLCγ1 and the intracellular part of FGFR1 and show that the interaction is centred on the nSH2 domain of PLCγ1. We define the architecture of PLCγ1 where an autoinhibitory interface involves the cSH2, spPH, TIM-barrel and C2 domains; this relative orientation occludes PLCγ1 access to its substrate. Based on this framework and functional characterization, the mechanism leading to an increase in PLCγ1 activity for the largest group of mutations is consistent with the major, direct impact on the autoinhibitory interface. INTERPRETATION We reveal features of PLCγ enzymes that are important for determining their activation status. Targeting such features, as an alternative to targeting the PLC active site that has so far not been achieved for any PLC, could provide new routes for clinical interventions related to various pathologies driven by PLCγ deregulation. FUND: CR UK, MRC and AstaZeneca.

中文翻译：

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不同病理学中的结构见解和激活突变定义了磷脂酶 C γ 酶失调的机制。


背景PLCγ酶是细胞信号转导中的关键节点，其突变和罕见变体最近与一系列需求未得到满足的疾病的发展有关，包括癌症、复杂的免疫性疾病、炎症和神经退行性疾病。然而，激活的分子性质以及突变的影响和失调机制仍不清楚；两者都严重依赖于完整 PLCγ 酶的综合表征。方法 对于结构研究，我们应用了冷冻电镜、交联质谱和氢-氘交换质谱。与此同时，我们编制了与主要病理相关的突变，确定了它们的分布并评估了它们在细胞和体外的影响。研究结果我们定义了包含完整的自抑制 PLCγ1 和 FGFR1 细胞内部分的复合物的结构，并表明相互作用集中在 PLCγ1 的 nSH2 结构域上。我们定义了 PLCγ1 的架构，其中自动抑制接口涉及 cSH2、spPH、TIM-barrel 和 C2 结构域；这种相对方向阻止了 PLCγ1 与其底物的接触。基于该框架和功能表征，导致最大组突变的 PLCγ1 活性增加的机制与对自抑制界面的主要、直接影响一致。解释 我们揭示了 PLCγ 酶的特征，这些特征对于确定其激活状态非常重要。针对这些特征，作为迄今为止尚未在任何 PLC 中实现的针对 PLC 活性位点的替代方案，可以为与 PLCγ 失调驱动的各种病理相关的临床干预提供新途径。基金：CR UK、MRC 和阿斯塔捷利康。