An Atypical Minimal Kinase Inactivates the Molecular Chaperone Hsp90

Bacteria utilize a wide variety of proteins, termed effectors, to achieve virulence. We have identified an atypical kinase, HopBF1, found primarily in the plant pathogen Pseudomonas syringae. HopBF1 specifically inactivates Hsp90 causing the degradation of numerous Hsp90 clients, ultimately culminating in cell death and tissue necrosis. We further propose a remarkable betrayal mechanism in which HopBF1 masquerades as a host Hsp90 client to achieve specificity, followed by inactivation of the molecular chaperone.