Fig. 4.

The C-terminal transmembrane domain region of ABCG1 is essential for cellular localization and function. (A) Cos-7 cells were transfected with 1×FLAG-tagged ABCG1, ABCG2, or the indicated chimeric fusion proteins. Confocal images (taken at 63× magnification) are shown. White and red arrows identify immunofluorescent signals in endosomes and the plasma membrane, respectively. (B) CHO-K1 cells were transfected with an empty/control plasmid or plasmids encoding the indicated protein and cholesterol efflux to HDL determined as described in Fig. 3. (C) CHO-K1 cells were cotransfected with pSynSRE and the indicated plasmid before determination of luciferase activity, as described in Fig. 3. Data in B and C are representative of two to three different experiments, each performed in sextuplet. *P < 0.05; ***P < 0.001 vs. cells transfected with pSynSRE and empty plasmid.