Type III secretion system needle-tip protein PcrV (Pseudomonas aeruginosa) (PcrV)

Type III secretion system needle-tip protein PcrV is a critical component of the type III secretion system (T3SS) in Pseudomonas aeruginosa, an opportunistic pathogen. It localizes at the distal end of the T3SS needle, serving as the key assembly platform for the translocon pore that mediates the injection of bacterial effector toxins into host cells. PcrV is indispensable for the insertion of translocator proteins PopB and PopD, enabling pore formation in the host membrane. Besides its structural role, PcrV has immunomodulatory properties, triggering proinflammatory responses and serving as a protective antigen in vaccine strategies. Blocking PcrV—with neutralizing antibodies or small molecules—effectively inhibits T3SS function, reduces cytotoxicity, and attenuates infection, marking it as a validated anti-virulence therapeutic target. The protein is highly conserved and prevalent among clinical isolates, underlining its importance in disease and as a therapeutic target. Structural studies indicate that PcrV assembles as an oligomer at the needle tip and provides an interface for interaction with translocator proteins and host cell sensing.

Other names

V-antigen (in analogy to LcrV in Yersinia)Needle-tip protein of type III secretion system (T3SS) in Pseudomonas aeruginosa

Antibodies or small molecules bind PcrV, block assembly/function of the T3SS translocon, thus preventing effector translocation and reducing cytotoxicity/virulence. Antibody-mediated neutralization blocks PcrV-PopB/PopD interaction and inhibits pore formation necessary for toxin injection.