Fig. 4.

Mutant MCT8^L291R shows an overlapping expression pattern with the lysosomal marker LAMP1 in JEG1 cells. a Immunohistochemical staining confirms the translocation defect of untreated MCT8^L291R in MDCK1, JEG1, and COS7 cells. In COS7 cells MCT8^WT was hard to see at the plasma membrane, although T₃ transport activity was clearly present. NaPB reduced the intracellular storage of mutant MCT8^L291R. Anti-HA-antibody was used to stain wild-type and mutant MCT8 green. b Immunohistochemical costaining of MCT8^L291R (red) expressed in JEG1 cells as well as the ER marker PDI and the lysosomal marker LAMP1 (both green). Scale bars, 50 µm. ER, endoplasmic reticulum; HA, hemagglutinin; LAMP1, lysosomal-associated marker protein 1; MCT8, monocarboxylate transporter 8; MDCK1, Madin-Darby canine kidney; NaPB, sodium phenylbutyrate; PDI, protein disulfide isomerase; T₃, 3,3′,5-triiodothyronine.