Abstract
Type 3 secretion systems (T3SS) are essential virulence factors of numerous bacterial pathogens and inject effector proteins into host cells. The needle-like T3SS machinery consists of more than 20 components, has a length of around 100 nm and a diameter of up to 30 nm according to EM studies. Its intrabacterial components are highly dynamic and in permanent exchange with other bacterial structures. Therefore, a temporally and spatially resolved visualization of the T3SS using fluorescence microscopy techniques has been challenging. In the present study, novel labeling strategies were combined with super-resolution microscopy such as STED, STORM and MINFLUX. MINFLUX nanoscopy allowed to visualize components of the T3SS machinery such as the dynamic sorting platform component YscL and the extrabacterial pore protein YopD at unprecedented resolutions. The presented results represent the basis for an in depth investigation of T3SS structure and function and therefore gain new insights into the infection process of human pathogens in order to develop novel treatment and prevention strategies.
Competing Interest Statement
The authors declare the following competing interests. R.S., T.W. and C.A.W. are employees of Abberior Instruments manufacturing MINFLUX microscopes. C.A.W. is employee of Abberior commercializing fluorophores for super resolution. C.A.W. holds shares of Abberior Instruments. The other authors declare no competing interests.
Footnotes
Contact for questions concerning MINFLUX microscopy systems: c.wurm@abberior-instruments.com
Conceived and designed experiments: AC MR MW MA; Performed experiments: AC MR TW RS CAW MW; Analyzed the data: AC AVF; Contributed reagents/material/analysis tools/microscopes: TW RS CAW AD AVF; Wrote the paper: MA AC MW CAW AVF
