FIGURE 10.

Oligomerization of Oatp1d1. A, Western blot analysis of total cell lysate (TCL) of HEK293/Oatp1d1-overexpressing cells shows three forms of Oatp1d1: monomeric form (∼80 kDa), dimeric form (∼150 kDa), and oligomeric form (∼250 kDa). Western blot analysis of the membrane fraction (MF) of HEK293/Oatp1d1-overexpressing cells after the cell surface biotinylation with Sulfo-NHS-LC-LC-biotin and isolation of cell surface-biotinylated proteins with hydrophilic streptavidin magnetic beads shows only the oligomeric form. Western blots were performed in the presence of the reducing agent DTT with anti-His antibody and visualized with chemiluminescence. B, Western blot analysis of total cell lysate with and without DTT shows that without DTT, oligomers and dimers are present, whereas after the addition of DTT, the monomeric form appears, indicating that monomers form dimers through disulfide bonds.