Type III Secretion Translocon Structure and Function

描述（由申请方提供）：铜绿假单胞菌是医院获得性感染的常见原因。它使用III型分泌系统将效应蛋白直接注入靶向宿主细胞，特别是嗜中性粒细胞，从而防止宿主免疫系统的清除。效应蛋白的注射涉及称为易位子的专门结构，其由宿主细胞膜中的孔组成，所述孔与III型分泌针的尖端相互作用。虽然易位子对于III型分泌功能是关键的，但它很难进行生物化学研究。在这里，我们建议使用一种遗传技术来确定关键的易位相互作用，并根据它们在易位过程中的功能（易位插入，孔形成，对接的尖端孔和触发效应分泌）进行分类。识别对功能至关重要的易位接触不仅增加了我们对易位子的理解，还确定了治疗的潜在靶点。 干预位于细菌细胞之外，因此不受常规抗生素耐药性机制（如外膜或外排泵）的屏蔽。

DESCRIPTION (provided by applicant): P. aeruginosa is a common cause of hospital-acquired infections. It uses a type III secretion system to directly inject effector proteins into targeted host cells, in particular neutrophils, thereby preventing clearance by the host immune system. Injection of effector proteins involves a specialized structure called the translocon, which consists of a pore in the host cell membrane that interacts with the tip of the type III secretion needle. While the translocon is critical for type III secretion function, it has been difficult to study biochemically. Here we propose to use a genetic technique to identify critical translocator interactions and categorize them according to their function in the translocation process (translocator insertion, pore formation, docking of the tip to the pore and triggering of effector secretion). Identifying translocator contacts that are critical for function not only increases our understanding of the translocon, it also identifies potential targets for therapeutic intervention that lie outside of the bacterial cell and are therefore not shielded by conventional antibiotic resistance mechanisms, such as the outer membrane or efflux pumps.