FIGURE 9.

Surface biotinylation of FXYD proteins in H1299 cells. A, H1299 cells stably expressing YFP-α1 Na⁺/K⁺ ATPase and the above CFP-tagged FXYD proteins were surface-biotinylated with sulfo-NHS-SS biotin. Cells were lysed and subjected to streptavidin pull-down as described under “Experimental Procedures.” 5% of the total cell lysate (T) and all of the streptavidin bound proteins (PD) were resolved electrophoretically and blotted with anti-HA and anti-α1 antibodies. α1 Na⁺/K⁺ ATPase migrates as a doublet corresponding to normal and YFP-tagged polypeptides. B, a second experiment using the same protocol that better demonstrates the FXYD7 doublet.