Actin growth profile in clathrin-mediated endocytosis

D. J. Tweten, P. V. Bayly, and A. E. Carlsson
Phys. Rev. E 95, 052414 – Published 23 May 2017

Abstract

Clathrin-mediated endocytosis in yeast is driven by a protein patch containing close to 100 different types of proteins. Among the proteins are 500010000 copies of polymerized actin, and successful endocytosis requires growth of the actin network. Since it is not known exactly how actin network growth drives endocytosis, we calculate the spatial distribution of actin growth required to generate the force that drives the process. First, we establish the force distribution that must be supplied by actin growth, by combining membrane-bending profiles obtained via electron microscopy with established theories of membrane mechanics. Next, we determine the profile of actin growth, using a continuum mechanics approach and an iterative procedure starting with an actin growth profile obtained from a linear analysis. The profile has fairly constant growth outside a central hole of radius 45–50 nm, but very little growth in this hole. This growth profile can reproduce the required forces if the actin shear modulus exceeds 80 kPa, and the growing filaments can exert very large polymerization forces. The growth profile prediction could be tested via electron-microscopy or super-resolution experiments in which the turgor pressure is suddenly turned off.

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  • Received 8 February 2017
  • Revised 1 May 2017

DOI:https://doi.org/10.1103/PhysRevE.95.052414

©2017 American Physical Society

Physics Subject Headings (PhySH)

Physics of Living Systems

Authors & Affiliations

D. J. Tweten1, P. V. Bayly1, and A. E. Carlsson2

  • 1Department of Mechanical Engineering, Washington University, St. Louis, Missouri 63130, USA
  • 2Department of Physics, Washington University, St. Louis, Missouri 63130, USA

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Issue

Vol. 95, Iss. 5 — May 2017

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