ExsA
ExsA is a transcriptional activator in Pseudomonas aeruginosa that controls the expression of the bacterium’s Type III secretion system (T3SS). It belongs to the AraC family of transcriptional regulators and functions by directly binding to promoter regions of T3SS regulon genes to initiate transcription. ExsA activates a set of operons and effector genes, including those in the exsCEBA operon and key virulence factors such as exoS, exoT, exoU, and exoY, thereby enabling the assembly and deployment of the T3SS.
Regulation of ExsA activity is orchestrated by the ExsC-ExsD-ExsE regulatory module. In non-inducing conditions, ExsD binds
Structurally, ExsA operates as a dimeric transcriptional activator within the AraC family and requires promoter binding