FIGURE 8.

SMSs form homodimers in the ER membrane. A and B, COS7 cells were incubated for 14 h in the presence or absence of 50 nm BFA. Then the cells were transfected with a plasmid encoding V5-tagged SMS1 or SMS2 and cultured for an additional 24 h. A, the cells were stained with anti-V5 (SMS1 or SMS2) and anti-PDI (an ER marker) antibodies, followed by appropriate Alexa Fluor-conjugated secondary antibodies, and analyzed by confocal microscopy. SMS1 or SMS2, green; PDI, red. Scale bar = 40 μm. B, the membrane extracts were resolved by BN-PAGE and detected by immunoblotting with anti-V5 antibody. The results are from one experiment representative of three independent experiments.