The type IX secretion system (T9SS) is specific to the Bacteroidetes phylum. Porphyromonas gingivalis, a keystone pathogen for periodontitis, utilises the T9SS to transport many proteins—including its gingipain virulence factors—across the outer membrane and attach them to the cell surface. Additionally, the T9SS is also required for gliding motility in motile organisms, such as Flavobacterium johnsoniae. At least nineteen proteins have been identified as components of the T9SS, including the three transcription regulators, PorX, PorY and SigP. Although the components are known, the overall organisation and the molecular mechanism of how the T9SS operates is largely unknown. This review focusses on the recent advances made in the structure, function, and organisation of the T9SS machinery to provide further insight into this highly novel secretion system.

中文翻译：

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IX型分泌系统：结构，功能和组织方面的进步。

IX型分泌系统（T9SS）特异于拟杆菌。牙龈卟啉单胞菌（Porphyromonas gingivalis）是牙周炎的关键病原体，它利用T9SS跨外膜运输许多蛋白质（包括其gingipain毒力因子）并将其附着在细胞表面。另外，T9SS还需要在运动性生物体（如约翰逊黄杆菌）中滑动运动。已经鉴定出至少十九种蛋白质作为T9SS的成分，包括三种转录调节因子PorX，PorY和SigP。尽管组件已知，但T9SS运作的总体组织和分子机制尚不清楚。这篇综述着重于T9SS机械的结构，功能和组织方面的最新进展，以进一步了解这种高度新颖的分泌系统。