Fig. 5. GFP-tagging experiments indicate that the erasin sequence between residues 414 to 434 is both necessary and sufficient for ER localization. (A) Schematic diagram of GFP-tagged erasin constructs and summary of their localization obtained by live cell imaging and biochemical fractionation on gradients. The hydrophobic patch (HP) that is responsible for ER localization is indicated. (B) Representative examples of the fluorescent images taken of live cells following transfection with different GFP-tagged erasin constructs. (C) Helical wheel representation of the hydrophobic targeting sequence and comparison with that of caveolin-1. Note the position of the putative helix-disrupting proline residue in both sequences (see text).