Clathrin, AP-2, and the NPXY-binding subset of alternate endocytic adaptors facilitate FimH-mediated bacterial invasion of host cells
Clathrin, AP-2, and the NPXY-binding subset of alternate endocytic adaptors facilitate FimH-mediated bacterial invasion of host cells
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DOI：
10.1111/j.1462-5822.2008.01229.x
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发表时间：
2008-12-01
影响因子：
3.4
通讯作者：
Dhakal, Bijaya K.
中科院分区：
文献类型：
--
作者：
Eto, Danelle S.;Gordon, Hannah B.;Dhakal, Bijaya K.
FimH 粘附素位于 1 型菌毛的远端，与 α3β1 整合素等含甘露糖的糖蛋白受体结合，并刺激细菌进入目标宿主细胞。尿路致病性大肠杆菌 (UPEC) 菌株是尿路感染的主要原因，它利用 FimH 侵入膀胱上皮细胞。在这里，我们着手通过研究已知的入侵病原体利用的四种主要进入途径来定义 UPEC 进入宿主细胞的机制：小窝、网格蛋白、巨胞饮作用和分泌性溶酶体。使用药理学抑制剂与针对特定内吞途径成分、突变宿主细胞系和小鼠感染模型系统的RNA干扰相结合，我们发现1型菌毛依赖性细菌对宿主细胞的入侵是通过胆固醇和动力依赖性吞噬作用样机制发生的。该过程不需要小窝或分泌性溶酶体，但受到钙水平、网格蛋白以及来自主要网格蛋白接头 AP-2 和由 Numb、ARH 和 Dab2 组成的替代接头子集的协作输入的调节。这些替代的网格蛋白接头可识别 NPXY 基序，如在 β1 整联蛋白的胞质尾部中发现的那样，表明 FimH 与整联蛋白受体的结合与 1 型毛毛细菌的网格蛋白依赖性摄取之间存在功能联系。
The FimH adhesin, localized at the distal tips of type 1 pili, binds mannose-containing glycoprotein receptors like alpha 3 beta 1 integrins and stimulates bacterial entry into target host cells. Strains of uropathogenic Escherichia coli (UPEC), the major cause of urinary tract infections, utilize FimH to invade bladder epithelial cells. Here we set out to define the mechanism by which UPEC enters host cells by investigating four of the major entry routes known to be exploited by invasive pathogens: caveolae, clathrin, macropinocytosis and secretory lysosomes. Using pharmacological inhibitors in combination with RNA interference against specific endocytic pathway components, mutant host cell lines and a mouse infection model system, we found that type 1 pili-dependent bacterial invasion of host cells occurs via a cholesterol- and dynamin-dependent phagocytosis-like mechanism. This process did not require caveolae or secretory lysosomes, but was modulated by calcium levels, clathrin, and cooperative input from the primary clathrin adaptor AP-2 and a subset of alternate adaptors comprised of Numb, ARH and Dab2. These alternate clathrin adaptors recognize NPXY motifs, as found within the cytosolic tail of beta 1 integrin, suggesting a functional link between the engagement of integrin receptors by FimH and the clathrin-dependent uptake of type 1-piliated bacteria.