Identification of proteins associated with the PDZ-binding motif of Syx. (A) A peptide corresponding to the last 19 amino acids of Syx was used for pull-down experiments in MAE cells. Proteins that bound to peptides were separated by SDS-PAGE and visualized by silver staining and analyzed by mass spectrometry. The identity of bands indicated by asterisks is shown in the figure as well as in Table S1. (B) Pals1, Patj, and Mupp1 binding to Amot was verified by coimmunoprecipitation analysis in HEK 293 cells as indicated. The Syx ΔEV (lacking 2 aa's in the PDZ-binding motif) was used as negative control.