Protein crowding mediates membrane remodeling in upstream ESCRT-induced formation of intraluminal vesicles

Susanne Liese, Eva Maria Wenzel, Ingrid Kjos, Rossana Rojas Molina, Sebastian W. Schultz, Andreas Brech, Harald Stenmark, Camilla Raiborg, Andreas Carlson
2020 Proceedings of the National Academy of Sciences of the United States of America  
As part of the lysosomal degradation pathway, the endosomal sorting complexes required for transport (ESCRT-0 to -III/VPS4) sequester receptors at the endosome and simultaneously deform the membrane to generate intraluminal vesicles (ILVs). Whereas ESCRT-III/VPS4 have an established function in ILV formation, the role of upstream ESCRTs (0 to II) in membrane shape remodeling is not understood. Combining experimental measurements and electron microscopy analysis of ESCRT-III–depleted cells with
more » ... mathematical model, we show that upstream ESCRT-induced alteration of the Gaussian bending rigidity and their crowding in concert with the transmembrane cargo on the membrane induce membrane deformation and facilitate ILV formation: Upstream ESCRT-driven budding does not require ATP consumption as only a small energy barrier needs to be overcome. Our model predicts that ESCRTs do not become part of the ILV, but localize with a high density at the membrane neck, where the steep decline in the Gaussian curvature likely triggers ESCRT-III/VPS4 assembly to enable neck constriction and scission.
doi:10.1073/pnas.2014228117 pmid:33139578 fatcat:fczwkdsn3zck3fuhejtiyzplka