HK-2 cells were stably transfected with RFP-tagged cystinosin-LKG or with its mutated form, deleted in C-terminal tail for the last five amino acids (ΔSSLKG). Cells were immunolabeled with LAMP-2 for lysosomes (A), PDI for endoplasmic reticulum (B), GM130 for Golgi (C). Scale bar = 10 μm. Analysis of ROIs (Regions of Interest) shows a Pearson’s Correlation (Rr) for RFP with LAMP-2 greater than with other organelle markers (p < 0.0005). In particular, the mutant ΔSSLKG shows an Rr for LAMP-2 significantly increased (p < 0.0005) compared to the wild type cystinosin-LKG. The presence of cystinosin-LKG and ΔSSLKG mutant on ER is low, moreover the analysis shows very low expression of cystinosin-LKG in the Golgi apparatus, whereas high Rr for GM130 in ΔSSLKG mutant suggests that it is accumulated significantly (p < 0.00001) on the Golgi apparatus (D). Means ± SEM of three experiments are shown.