FIGURE 3.
Efficient binding of clathrin adaptor proteins AP-1 and AP-2 to cytoplasmic tail peptides of E3/49K depends on the presence of the YXXΦ and LL motifs. The bottom panel shows the different cytoplasmic tail peptides used for the surface plasmon resonance spectroscopy studies with putative sorting signals in boldface type. YA is a mutant version with alanine substitution of the YXXΦ motif; LLAA is an altered version with alanine substitution of the LL motif; and YA/LLAA is a peptide with both motifs eliminated. Altered amino acids are shown in red. The equilibrium constants (KD) were determined in at least three independent experiments and are given in nm/liter ± S.D. The top panel shows the response versus time in seconds for the incubation of the different peptides with purified AP-1. n.d., not detectable. RU, resonance units.