Analysis of Yops Secretion by Yersinia pestis Type III Secretion System
The type III secretion system (T3SS) is a highly conserved virulence mechanism that is widely distributed in Gram-negative bacteria. Three pathogenic Yersinia species share a common T3SS encoded by a 70-kb plasmid called pCD1 or pYV. At least six Yersinia outer proteins (Yops) are injected via a needlelike structure called Ysc injectisome into the cytosol of eukaryotic cells, where these virulent proteins hijack host signaling pathways and interfere with the host immune system. T3SS secretion is contact-dependent, and both transcription and secretion of Yersinia T3SS are highly activated when the growth temperature shifts from 26 to 37 °C. Yersinia T3SS has evolved a sophisticated regulatory mechanism to control the assembly of the secretion apparatus as well as the secretion of substrates. Detection of substrates secreted by T3SS is essential for the investigation of injectisome assembly and secretion regulation of this fine-tuned virulence mechanism. This chapter describes the immunoblotting detection method for analyzing Yops secreted into the culture medium.
Key wordsYersinia pestis Type III secretion system (T3SS) Yops