Cells Respond to Mechanical Stress by Rapid Disassembly of Caveolae

Bidisha Sinha, Darius Köster, Richard Ruez, Pauline Gonnord, Michele Bastiani, Daniel Abankwa, Radu V. Stan, Gillian Butler-Browne, Benoit Vedie, Ludger Johannes, Nobuhiro Morone, Robert G. Parton, Graça Raposo, Pierre Sens, Christophe Lamaze, Pierre Nassoy

The functions of caveolae, the characteristic plasma membrane invaginations, remain debated. Their abundance in cells experiencing mechanical stress led us to investigate their role in membrane-mediated mechanical response. Acute mechanical stress induced by osmotic swelling or by uniaxial stretching results in a rapid disappearance of caveolae, in a reduced caveolin/Cavin1 interaction, and in an increase of free caveolins at the plasma membrane. Tether-pulling force measurements in cells and in plasma membrane spheres demonstrate that caveola flattening and disassembly is the primary actin- and ATP-independent cell response that buffers membrane tension surges during mechanical stress. Conversely, stress release leads to complete caveola reassembly in an actin- and ATP-dependent process. The absence of a functional caveola reservoir in myotubes from muscular dystrophic patients enhanced membrane fragility under mechanical stress. Our findings support a new role for caveolae as a physiological membrane reservoir that quickly accommodates sudden and acute mechanical stresses.