Dowd Georgina C, Bhalla Manmeet, Kean Bernard, Thomas Rowan, Ireton Keith
Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand.
Department of Microbiology and Immunology, University of Otago, Dunedin, New Zealand
Infect Immun. 2016 May 24;84(6):1826-1841. doi: 10.1128/IAI.00142-16. Print 2016 Jun.
Many bacterial pathogens subvert mammalian type IA phosphoinositide 3-kinase (PI3K) in order to induce their internalization into host cells. How PI3K promotes internalization is not well understood. Also unclear is whether type IA PI3K affects different pathogens through similar or distinct mechanisms. Here, we performed an RNA interference (RNAi)-based screen to identify components of the type IA PI3K pathway involved in invasin-mediated entry of Yersinia enterocolitica, an enteropathogen that causes enteritis and lymphadenitis. The 69 genes targeted encode known upstream regulators or downstream effectors of PI3K. A similar RNAi screen was previously performed with the food-borne bacterium Listeria monocytogenes The results of the screen with Y. enterocolitica indicate that at least nine members of the PI3K pathway are needed for invasin-mediated entry. Several of these proteins, including centaurin-α1, Dock180, focal adhesion kinase (FAK), Grp1, LL5α, LL5β, and PLD2 (phospholipase D2), were recruited to sites of entry. In addition, centaurin-α1, FAK, PLD2, and mTOR were required for remodeling of the actin cytoskeleton during entry. Six of the human proteins affecting invasin-dependent internalization also promote InlB-mediated entry of L. monocytogenes Our results identify several host proteins that mediate invasin-induced effects on the actin cytoskeleton and indicate that a subset of PI3K pathway components promote internalization of both Y. enterocolitica and L. monocytogenes.
许多细菌病原体破坏哺乳动物IA型磷酸肌醇3激酶（PI3K），以促使自身内化进入宿主细胞。PI3K如何促进内化作用尚未完全明确。IA型PI3K是否通过相似或不同的机制影响不同病原体也不清楚。在此，我们进行了一项基于RNA干扰（RNAi）的筛选，以鉴定IA型PI3K途径中参与侵袭素介导的小肠结肠炎耶尔森菌内化的成分，小肠结肠炎耶尔森菌是一种引起肠炎和淋巴结炎的肠道病原体。所靶向的69个基因编码PI3K已知的上游调节因子或下游效应器。之前对食源细菌单核细胞增生李斯特菌进行过类似的RNAi筛选。对小肠结肠炎耶尔森菌的筛选结果表明，侵袭素介导的内化作用至少需要PI3K途径的九个成员。其中一些蛋白质，包括centaurin-α1、Dock180、粘着斑激酶（FAK）、Grp1、LL5α、LL5β和PLD2（磷脂酶D2），被募集到内化位点。此外，centaurin-α1、FAK、PLD2和mTOR在侵入过程中对肌动蛋白细胞骨架的重塑是必需的。影响侵袭素依赖性内化的六种人类蛋白质也促进单核细胞增生李斯特菌InlB介导的内化。我们的结果鉴定了几种介导侵袭素对肌动蛋白细胞骨架诱导作用的宿主蛋白，并表明PI3K途径的一部分成分促进小肠结肠炎耶尔森菌和单核细胞增生李斯特菌的内化。
