Grove, J;
Metcalf, DJ;
Knight, AE;
Wavre-Shapton, ST;
Sun, T;
Protonotarios, E;
Griffin, LD;
... Marsh, M; + view all
(2014)
Flat Clathrin Lattices: stable features of the plasma membrane.
Mol Biol Cell
, 25
(22)
3581 - 3594.
10.1091/mbc.E14-06-1154.
PDF
Mol._Biol._Cell-2014-Grove-3581-94.pdf Download (5MB) |
Abstract
Clathrin-mediated endocytosis (CME) is a fundamental property of eukaryotic cells. Classical CME proceeds via the formation of clathrin-coated pits (CCP) at the plasma membrane that invaginate to form clathrin-coated vesicles; a process that is well understood. However, clathrin also assembles into flat clathrin lattices (FCL); these structures remain poorly described and their contribution to cell biology is unclear. We have used quantitative imaging to provide the first comprehensive description of FCL and explore their influence on plasma membrane organization. Ultrastructural analysis by electron and super-resolution microscopy revealed two discrete populations of clathrin structures. CCP were typified by their sphericity, small size and homogeneity. FCL were planar, large and heterogeneous, and present on both the dorsal and ventral surfaces of cells. Live microscopy demonstrated that CCP are short-lived and culminate in a peak of dynamin recruitment, consistent with classical CME. In contrast, FCL were long-lived with sustained association with dynamin. We investigated the biological relevance of FCL using the chemokine receptor CCR5 as a model system. Agonist activation leads to sustained recruitment of CCR5 to FCL. Quantitative molecular imaging indicated that FCL partitioned receptors at the cell surface. Our observations suggest that FCL provide stable platforms for the recruitment of endocytic cargo.
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