Figure 2. Functional analysis of changes in URAT1 expressed in HEK293 cells.
A. HEK293 cells were transiently transfected with Flag-tagged URAT1 cDNA constructs (wild-type and variants I75T, R347S, V388M, R434C and R434H). Plasma membrane expression was detected using an anti-FLAG monoclonal antibody, secondarily detected using an Alexa Fluor® 488 (green) antibody. Nuclei are counter stained using DAPI (blue). B. Uric acid uptake by HEK293 cells transiently transfected with wild-type URAT1 or its mutants was measured using [14C]Urate at 2 min, at 37°C and pH7.4. Significant reductions in urate transport activity was seen in some of the disease-associated variants. Data are mean ± S.E.M with n = 4. ***, P<0.001 when compared with wild type.