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BP: Fachverband Biologische Physik

BP 14: Poster Session II

BP 14.67: Poster

Dienstag, 10. März 2026, 18:00–21:00, P2

Dynamic Generation of Rigidity and Curvature during Clathrin-mediated Endocytosis — •Johannes Dreckhoff, Leon Lettermann, and Ulrich Schwarz — University of Heidelberg, Germany

Clathrin-mediated endocytosis is a main transport pathway across cell membranes, yet the physical mechanisms by which the clathrin coat assembles to drive generation of membrane curvature are not understood well. In particular, it has been argued that bending would not be possible if the coat attained its high stiffness already at the initial stages. Here we address this crucial issue using agent-based kinetic Monte Carlo simulations for coat assembly in spherical geometries with variable curvature. By formulating a microscopic Hamiltonian governing individual clathrin legs, we elucidate the interplay between lattice growth, topological defects, effective membrane stiffness and macroscopic curvature generation. Our simulations reveal that the effective bending rigidity of the coat increases by approximately two orders of magnitude during assembly, driving the curvature generation. We also observed the growth curvature imprinting itself onto the system, resulting in a "curvature memory" effect. Crucially, our simulations capture the distinct dynamical regimes observed in experiments: we successfully reproduce the flat-to-curved transition, while also predicting stalled, flat growth events, potentially driven by premature lattice stiffening. This unifying description demonstrates that clathrin-mediated endocytosis is a multi-facetted process during which rigidity and curvature are generated in a cooperative manner.

Keywords: clathrin-mediated endocytosis; curvature generation; self-assembly; kinetic monte carlo; biological lattice