Figure 3.
Immunoblot detection of cell-surface biotinylated Nramp1HA in independent CHO transfectants. Membrane protein fractions were prepared from independent CHO transfectants stably expressing Nramp1HA (N1-94, N1-116, N1-123, N1-1816) or Nramp2HA (N2-310a) and from CHO controls. These proteins (10 μg/lane) were analyzed by immunoblotting with affinity-purified rabbit polyclonal anti–Nramp1NT or anti–Nramp2NT, or with monoclonal anti–HA antibodies (panel A). In panel B, the cell lines were labeled by surface biotinylation (as described in “Materials and methods”), and biotinylated proteins captured with streptavidin-agarose beads were analyzed by immunoblotting with affinity-purified rabbit polyclonal anti–Nramp1NT or anti–Nramp2NT antibodies, or monoclonal anti–HA antibodies. The size of the molecular mass markers is shown to the left of the immunoblots.