Induced Membrane Curvature Bypasses Clathrin's Essential Endocytic Function

During clathrin-mediated endocytosis (CME), flat plasma membrane is rapidly remodeled to produce a nanometer-scale spherical vesicle. The mechanisms underlying this shape change are not known, but it has been hypothesized that the clathrin coat stabilizes membrane curvature. Here, we used nanopatterning to produce glass-like substrates with U-shaped features mimicking membrane shapes induced by fibrillar materials such as collagen. These substrates bend the ventral plasma membranes of cells grown on them into shapes characteristic of the energetically-unfavorable U-shaped intermediate stage of CME. This induced plasma membrane curvature recruits the endocytic machinery, enhances endocytic site maturation, and partially bypasses clathrin's role in CME, supporting the conclusion that clathrin's essential endocytic function is to stabilize membrane curvature.

Fluctuation tension and shape transition of vesicles: renormalisation calculations and Monte Carlo simulations

A quasi-spherical vesicle changes its shape to an oblate one at vanishing fluctuation surface tension.