Research ArticleBIOPHYSICS

Dynamic spectrin/ankyrin-G microdomains promote lateral membrane assembly by opposing endocytosis

Science Advances  11 Sep 2015:
Vol. 1, no. 8, e1500301
DOI: 10.1126/sciadv.1500301

You are currently viewing the abstract.

View Full Text

Abstract

Current physical models for plasma membranes emphasize dynamic 10- to 300-nm compartments at thermodynamic equilibrium but subject to thermal fluctuations. However, epithelial lateral membranes contain micrometer-sized domains defined by an underlying membrane skeleton composed of spectrin and its partner ankyrin-G. We demonstrate that these spectrin/ankyrin-G domains exhibit local microtubule-dependent movement on a time scale of minutes and encounter most of the lateral membranes within an hour. Spectrin/ankyrin-G domains exclude clathrin and clathrin-dependent cargo, and inhibit both receptor-mediated and bulk endocytosis. Moreover, inhibition of endocytosis fully restores lateral membrane height in spectrin- or ankyrin-G–depleted cells. These findings support a non-equilibrium cellular-scale model for epithelial lateral membranes, where spectrin/ankyrin-G domains actively patrol the plasma membrane, analogous to “window washers,” and promote columnar morphology by blocking membrane uptake.

Keywords
  • ankyrin-G
  • spectrin
  • palmitoylation
  • epithelial lateral membrane
  • clathrin
  • endocytosis
  • plasma membrane
  • microdomain

This is an open-access article distributed under the terms of the Creative Commons Attribution-NonCommercial license, which permits use, distribution, and reproduction in any medium, so long as the resultant use is not for commercial advantage and provided the original work is properly cited.

View Full Text

More Like This