Consequences of the ER-resident trafficking deficient CLN5 on the localization of PPT1/CLN1 and CLN3 in HeLa cells. HeLa cells were transiently transfected with the trafficking deficient CLN5 (CLN5-TD) carrying the intramolecular flag-tag after aa 330, alone, or together with wild type PPT1 or CLN3. The cells were fixed with methanol 48 h post transfection, stained and analyzed by confocal microscopy. CLN5-TD co-localized with the ER marker PDI (A-C). When transfected together with PPT1, CLN5-TD retained the wild type PPT1 also in the ER (D-F), (compare the two cells in E positive for PPT1 with and without CLN5-TD), whereas overexpression of the ER resident CLN6 did not have an influence on PPT1 trafficking (G-I). The CLN5-TD partially affected also the lysosomal targeting of the wild type CLN3 (J-L). Scale bar 10 μm.