Biophysical Society Thematic Meeting | Ascona 2026

Mechanobiology of Infection

Sunday Speaker Abstracts

MECHANICAL COMPRESSION ACTIVATES CAMP SIGNALING IN PSEUDOMONAS AERUGINOSA Fan Jin ; Shenzhen Institute of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China In Pseudomonas aeruginosa, cyclic AMP (cAMP) is a critical regulator of the type III secretion system (T3SS), whose abundance directly impacts bacterial virulence. Yet, the environmental signals that activate cAMP signaling remain incompletely understood. Here, using the real-time cAMP biosensor Gflamp1, we demonstrate that mechanical compression triggers cAMP elevation in P. aeruginosa. Combining microfluidics, image processing, and physical modelling, we estimated a mechanical force threshold of ~30 nN for cAMP activation. Genetic studies revealed that this mechanoresponse depends on the Pil-Chp chemotaxis system and the FimV FimL complex, along with the adenylate cyclase CyaB, but does not require surface-exposed type IV pili. We demonstrated direct interaction between the histidine kinase ChpA and the polar scaffolding protein FimV, and that FimL competes with ChpA for FimV binding. FRET-FLIM analysis indicated that ChpA moves closer to both PilG and FimL under mechanical compression. We further showed global upregulation of T3SS-associated genes during compressed-state bacterial growth. These findings offer insights into the dynamic processes underlying bacterial infection in host organisms.

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