PTPδ recruitment to dendrites by IL1RAPL1 cis-interaction. A, Hippocampal neurons were transfected at DIV 11 with GFP, HA-IL1RAPL1, and IL1RAPL1 in combination with HA-PTPδ and HA-PTPδ A−B− (HA-PTPδ without miniexons A and B), and HA-TSPAN7. At DIV 14–15, live hippocampal neurons were subjected to a surface staining. Total (blue signal) and surface (red signal) staining using anti-HA tag antibody are shown. B, The graph shows ratios of average intensity of surface HA signal per total HA signal measured for each neuron. All values represent mean ± SEM. *p < 0.05, compared with GFP+PTPδ condition (Student's t test.). C, Lysates from COS-7 cells coexpressing the indicated IL1RAPL1 and HA-PTPδ constructs were subjected to immunoprecipitation assay using rabbit anti-HA or rabbit IgG antibody. Ten percent of the lysate used for the immunoprecipitation and immunoprecipitate proteins were detected after immunoblotting using goat anti-IL1RAPL1 and mouse anti-HA antibodies. D, The images show coclustering assay in COS-7-transfected and stained with the indicated constructs.