Pressure-induced membrane tension mechanically opens the germinant receptor GerA ion channel to trigger bacterial spore germination.

Moderate high pressure (50–300 MPa) in Bacillus subtilis is linked to primary activation of the GerA germinant receptor, requiring GerA pore-lining residues.

• Why it matters: The biophysical mechanism by which high pressure activates membrane-embedded spore proteins has been unclear, limiting understanding of how spores reliably sense and respond to pressure.
• What they did: The study used GerA mutagenesis, in situ membrane tension measurements, and pressure-dependent permeability assays with propidium iodide and formaldehyde, plus heat or decoating to alter inner membrane properties.
• The result: High pressure compresses inner membrane phospholipids, elevates lateral membrane tension, and promotes GerA opening, supporting a stretch-to-open model and delaying germination when inner membrane physical properties are modified.

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