An Indispensable Role for the MavE Effector of Legionella pneumophila in Lysosomal Evasion.
An Indispensable Role for the MavE Effector of Legionella pneumophila in Lysosomal Evasion.
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DOI：
10.1128/mbio.03458-20
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发表时间：
2021-02-09
期刊：
影响因子：
6.4
通讯作者：
Abu Kwaik Y
中科院分区：
文献类型：
--
作者：
Vaughn B;Voth K;Price CT;Jones S;Ozanic M;Santic M;Cygler M;Abu Kwaik Y
人肺泡巨噬细胞液泡内嗜肺军团菌的细胞内增殖对于军团肺炎的表现至关重要。病原体的液泡内生长完全依赖于内质网对含有嗜肺军团菌的液泡（LCV）的重塑以及其对内体-溶酶体降解途径的逃避。含有嗜肺军团菌的液泡（LCV）从宿主内体-溶酶体降解途径中转移是军团菌肺炎表现所必需的主要毒力特征之一。在嗜肺军团菌中鉴定出的许多约 350 点/Icm 注射效应子已被证明会干扰各种宿主途径和过程，但尚未发现嗜肺军团菌效应子对于溶酶体逃逸是不可或缺的。虽然嗜肺军团菌的大多数单一效应突变体在巨噬细胞内不表现出有缺陷的表型，但我们表明，MavE效应子对于嗜肺军团菌在人单核细胞源性巨噬细胞（hMDM）和阿米巴原虫中的细胞内生长以及小鼠的肺内增殖至关重要。 mavE无效突变体无法用内质网（ER）来源的囊泡重塑LCV，并被运输到溶酶体并在那里被降解，类似于福尔马林杀死的细菌。在 hMDM 感染期间，MavE 效应器定位于 LCV 膜的两极。 MavE 的晶体结构分辨率为 1.8 Å，揭示了一个 C 端跨膜螺旋、三个基于酪氨酸的分选基序拷贝以及一个 NPxY 真核基序，该基序与信号传导和接头真核蛋白上存在的磷酸酪氨酸结合域结合。 NPxY 基序内的两个点突变导致嗜肺军团菌在 hMDM 和阿米巴原虫中减弱。 P78 和 D64 的取代缺陷与内质网重塑含有突变体的液泡失败有关，并导致液泡与溶酶体融合，导致细菌降解。因此，嗜肺军团菌的MavE效应子对于吞噬体的生物发生和溶酶体逃逸是不可或缺的。
Intracellular proliferation of Legionella pneumophila within a vacuole in human alveolar macrophages is essential for manifestation of Legionnaires’ pneumonia. Intravacuolar growth of the pathogen is totally dependent on remodeling the L. pneumophila-containing vacuole (LCV) by the ER and on its evasion of the endosomal-lysosomal degradation pathway. Diversion of the Legionella pneumophila-containing vacuole (LCV) from the host endosomal-lysosomal degradation pathway is one of the main virulence features essential for manifestation of Legionnaires’ pneumonia. Many of the ∼350 Dot/Icm-injected effectors identified in L. pneumophila have been shown to interfere with various host pathways and processes, but no L. pneumophila effector has ever been identified to be indispensable for lysosomal evasion. While most single effector mutants of L. pneumophila do not exhibit a defective phenotype within macrophages, we show that the MavE effector is essential for intracellular growth of L. pneumophila in human monocyte-derived macrophages (hMDMs) and amoebae and for intrapulmonary proliferation in mice. The mavE null mutant fails to remodel the LCV with endoplasmic reticulum (ER)-derived vesicles and is trafficked to the lysosomes where it is degraded, similar to formalin-killed bacteria. During infection of hMDMs, the MavE effector localizes to the poles of the LCV membrane. The crystal structure of MavE, resolved to 1.8 Å, reveals a C-terminal transmembrane helix, three copies of tyrosine-based sorting motifs, and an NPxY eukaryotic motif, which binds phosphotyrosine-binding domains present on signaling and adaptor eukaryotic proteins. Two point mutations within the NPxY motif result in attenuation of L. pneumophila in both hMDMs and amoeba. The substitution defects of P78 and D64 are associated with failure of vacuoles harboring the mutant to be remodeled by the ER and results in fusion of the vacuole to the lysosomes leading to bacterial degradation. Therefore, the MavE effector of L. pneumophila is indispensable for phagosome biogenesis and lysosomal evasion.