Mostowy Serge, Nam Tham To, Danckaert Anne, Guadagnini Stéphanie, Boisson-Dupuis Stéphanie, Pizarro-Cerdá Javier, Cossart Pascale
Institut Pasteur, Unité des Interactions Bactéries-Cellules, Paris, France.
PLoS One. 2009;4(1):e4196. doi: 10.1371/journal.pone.0004196. Epub 2009 Jan 15.
Septins are conserved GTPases that form filaments and are required in many organisms for several processes including cytokinesis. We previously identified SEPT9 associated with phagosomes containing latex beads coated with the Listeria surface protein InlB.
METHODOLOGY/PRINCIPAL FINDINGS: Here, we investigated septin function during entry of invasive bacteria in non-phagocytic mammalian cells. We found that SEPT9, and its interacting partners SEPT2 and SEPT11, are recruited as collars next to actin at the site of entry of Listeria and Shigella. SEPT2-depletion by siRNA decreased bacterial invasion, suggesting that septins have roles during particle entry. Incubating cells with InlB-coated beads confirmed an essential role for SEPT2. Moreover, SEPT2-depletion impaired InlB-mediated stimulation of Met-dependent signaling as shown by FRET.
CONCLUSIONS/SIGNIFICANCE: Together these findings highlight novel roles for SEPT2, and distinguish the roles of septin and actin in bacterial entry.
Septin是一类保守的GTP酶，可形成细丝，在许多生物体的包括胞质分裂在内的多个过程中发挥作用。我们之前鉴定出SEPT9与含有包被李斯特菌表面蛋白InlB的乳胶珠的吞噬体相关。
方法/主要发现：在此，我们研究了侵袭性细菌进入非吞噬性哺乳动物细胞过程中septin的功能。我们发现，SEPT9及其相互作用伙伴SEPT2和SEPT11在李斯特菌和志贺氏菌进入位点处作为肌动蛋白旁的环被募集。通过siRNA敲低SEPT2可减少细菌入侵，这表明septin在颗粒进入过程中发挥作用。用包被InlB的珠子孵育细胞证实了SEPT2的重要作用。此外，如FRET所示，敲低SEPT2会损害InlB介导的Met依赖性信号传导的刺激。
结论/意义：这些发现共同突出了SEPT2的新作用，并区分了septin和肌动蛋白在细菌进入中的作用。
