@article{14782,
  abstract     = {The actin cortex is a complex cytoskeletal machinery that drives and responds to changes in cell shape. It must generate or adapt to plasma membrane curvature to facilitate diverse functions such as cell division, migration, and phagocytosis. Due to the complex molecular makeup of the actin cortex, it remains unclear whether actin networks are inherently able to sense and generate membrane curvature, or whether they rely on their diverse binding partners to accomplish this. Here, we show that curvature sensing is an inherent capability of branched actin networks nucleated by Arp2/3 and VCA. We develop a robust method to encapsulate actin inside giant unilamellar vesicles (GUVs) and assemble an actin cortex at the inner surface of the GUV membrane. We show that actin forms a uniform and thin cortical layer when present at high concentration and distinct patches associated with negative membrane curvature at low concentration. Serendipitously, we find that the GUV production method also produces dumbbell-shaped GUVs, which we explain using mathematical modeling in terms of membrane hemifusion of nested GUVs. We find that branched actin networks preferentially assemble at the neck of the dumbbells, which possess a micrometer-range convex curvature comparable with the curvature of the actin patches found in spherical GUVs. Minimal branched actin networks can thus sense membrane curvature, which may help mammalian cells to robustly recruit actin to curved membranes to facilitate diverse cellular functions such as cytokinesis and migration.},
  author       = {Baldauf, Lucia and Frey, Felix F and Arribas Perez, Marcos and Idema, Timon and Koenderink, Gijsje H.},
  issn         = {0006-3495},
  journal      = {Biophysical Journal},
  keywords     = {Biophysics},
  number       = {11},
  pages        = {2311--2324},
  publisher    = {Elsevier},
  title        = {{Branched actin cortices reconstituted in vesicles sense membrane curvature}},
  doi          = {10.1016/j.bpj.2023.02.018},
  volume       = {122},
  year         = {2023},
}

@article{14788,
  abstract     = {Eukaryotic cells use clathrin-mediated endocytosis to take up a large range of extracellular cargo. During endocytosis, a clathrin coat forms on the plasma membrane, but it remains controversial when and how it is remodeled into a spherical vesicle.
Here, we use 3D superresolution microscopy to determine the precise geometry of the clathrin coat at large numbers of endocytic sites. Through pseudo-temporal sorting, we determine the average trajectory of clathrin remodeling during endocytosis. We find that clathrin coats assemble first on flat membranes to 50% of the coat area before they become rapidly and continuously bent, and this mechanism is confirmed in three cell lines. We introduce the cooperative curvature model, which is based on positive feedback for curvature generation. It accurately describes the measured shapes and dynamics of the clathrin coat and could represent a general mechanism for clathrin coat remodeling on the plasma membrane.},
  author       = {Mund, Markus and Tschanz, Aline and Wu, Yu-Le and Frey, Felix F and Mehl, Johanna L. and Kaksonen, Marko and Avinoam, Ori and Schwarz, Ulrich S. and Ries, Jonas},
  issn         = {1540-8140},
  journal      = {Journal of Cell Biology},
  keywords     = {Cell Biology},
  number       = {3},
  publisher    = {Rockefeller University Press},
  title        = {{Clathrin coats partially preassemble and subsequently bend during endocytosis}},
  doi          = {10.1083/jcb.202206038},
  volume       = {222},
  year         = {2023},
}