pY374-PKCδ stabilizes association of RAB5 and RAB7 with EGFR-containing endosomes. (a–f) EGFR-containing endosomes (Alexa Fluor 488) and the indicated RABs (Alexa Fluor 594) in control pCas9Vec (clone a) or PTPN14-KO (two clones, c1 and o) BT-549 cells were fluorescently tagged as described in Fig. 6. Representative confocal micrographs of EGFR-containing endosomes costained with RAB5 (a), RAB7 (c), or RAB11 (e) 60 min after inducing endocytosis with 20 ng/ml EGF (arrowheads indicate colocalization), and quantified data of colocalization of EGFR-containing endosomes with RAB5 (b), RAB7 (d), or RAB11 (f) from confocal micrographs (mean ± SEM; n > 30 cells; ns, not significant; **, P < 0.01; ***, P < 0.001 using one-way ANOVA with Bonferroni multiple comparisons post-test).