Dynamic spectrin/ankyrin-G microdomains promote lateral membrane assembly by opposing endocytosis.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 26523289.
- Also identified by DOI 10.1126/sciadv.1500301 and PMC identifier 4624203.
- Licence recorded as CC BY-NC.
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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.