Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.
Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Quantitative Biosciences Institute (QBI), University of California, San Francisco, San Francisco, CA 94148, USA; Gladstone Institutes, San Francisco, CA 94158, USA.
Mol Cell. 2018 Aug 16;71(4):637-648.e5. doi: 10.1016/j.molcel.2018.07.010.
Although macrophages are armed with potent antibacterial functions, Mycobacterium tuberculosis (Mtb) replicates inside these innate immune cells. Determinants of macrophage intrinsic bacterial control, and the Mtb strategies to overcome them, are poorly understood. To further study these processes, we used an affinity tag purification mass spectrometry (AP-MS) approach to identify 187 Mtb-human protein-protein interactions (PPIs) involving 34 secreted Mtb proteins. This interaction map revealed two factors involved in Mtb pathogenesis-the secreted Mtb protein, LpqN, and its binding partner, the human ubiquitin ligase CBL. We discovered that an lpqN Mtb mutant is attenuated in macrophages, but growth is restored when CBL is removed. Conversely, Cbl macrophages are resistant to viral infection, indicating that CBL regulates cell-intrinsic polarization between antibacterial and antiviral immunity. Collectively, these findings illustrate the utility of this Mtb-human PPI map for developing a deeper understanding of the intricate interactions between Mtb and its host.
尽管巨噬细胞具有强大的抗菌功能，但结核分枝杆菌（Mtb）在这些先天免疫细胞内复制。巨噬细胞固有细菌控制的决定因素，以及 Mtb 克服这些因素的策略，人们知之甚少。为了进一步研究这些过程，我们使用亲和标签纯化质谱（AP-MS）方法来鉴定 187 种涉及 34 种分泌性 Mtb 蛋白的 Mtb-人蛋白-蛋白相互作用（PPIs）。该相互作用图谱揭示了两种参与 Mtb 发病机制的因素-分泌性 Mtb 蛋白 LpqN 及其结合伴侣，人类泛素连接酶 CBL。我们发现 Mtb 突变体 lpqN 在巨噬细胞中衰减，但当去除 CBL 时，生长恢复。相反，Cbl 巨噬细胞对病毒感染具有抗性，表明 CBL 调节了抗菌和抗病毒免疫之间的细胞内在极化。总之，这些发现说明了这种 Mtb-人 PPI 图谱的实用性，可用于深入了解 Mtb 与其宿主之间复杂的相互作用。
