Protein-retention ExM (proExM) of HeLa cells using acryloyl-X, SE (AcX) as the protein anchor. a Dual-color proExM of clathrin (fused to mEmerald, green) and keratin (mRuby2, red). Two representative images are shown. Scale bar, 1 μm (4.3 μm; here and after, physical size after the expansion, if available, is shown in brackets). b Dual-color proExM image of actin (mRuby2, red) and paxillin (mEmerald, green) fusions. Insets are magnified views of the boxed regions. Scale bars, 5 μm (21.5 μm) and 1 μm (4.3 μm, insets).