A plasma membrane template for macropinocytic cups.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 27960076.
- Also identified by DOI 10.7554/eLife.20085 and PMC identifier 5154761.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
Macropinocytosis is a fundamental mechanism that allows cells to take up extracellular liquid into large vesicles. It critically depends on the formation of a ring of protrusive actin beneath the plasma membrane, which develops into the macropinocytic cup. We show that macropinocytic cups in <i>Dictyostelium</i> are organised around coincident intense patches of PIP<sub>3</sub>, active Ras and active Rac. These signalling patches are invariably associated with a ring of active SCAR/WAVE at their periphery, as are all examined structures based on PIP<sub>3</sub> patches, including phagocytic cups and basal waves. Patch formation does not depend on the enclosing F-actin ring, and patches become enlarged when the RasGAP NF1 is mutated, showing that Ras plays an instructive role. New macropinocytic cups predominantly form by splitting from existing ones. We propose that cup-shaped plasma membrane structures form from self-organizing patches of active Ras/PIP<sub>3</sub>, which recruit a ring of actin nucleators to their periphery.
Medical subject headings
- Actin Cytoskeleton
- Cell Membrane
- Dictyostelium
- Pinocytosis