Elastin‐like polypeptides can be expressed in eukaryotic cells in fusion with functional proteins. When heated, they assemble organelle‐sized microdomains that sequester target complexes. On page 5340, J. A. MacKay and team demonstrate that, by fusion to clathrin‐light chain, these microdomains co‐localize and sequester clathrin heavy chain, which is necessary for clathrin‐mediated endocytosis. Assembly rapidly and reversibly blocks internalization of G‐protein coupled receptors. Image created by Isaac Mora.