FIGURE 1.

UIM regions in the proteasomal subunit S5a and the endocytotic protein Eps15. A, sequence alignment of the UIM containing regions from Homo sapiens S5a and Eps15 (30). The sequence of S5a, containing a 5-alanine substitution in the second UIM S5a-(196–309)^UIMII-5A is also shown. The UIM motif identified by Hofmann and Falquet (30) is shown below, where Φ is a large hydrophobic residue, e/d denotes a preference for an acidic residue, and X is any amino acid. The constructs used in this work extend from residues 196–309 in S5a (S5a-(196–309)) and 846–896 in Eps15 (Eps15-(846–896)). A box with inset numbers indicates the number of residues in the inter-UIM linker for S5a and Eps15. B, ribbon drawing of the three-dimensional structure of S5a-(196–309) (Protein Data Bank code 1YX4) (33) highlighting the regions (red) for the central hydrophobic regions of UIM I and II. This figure was produced using the program PyMOL (52).