Figure 2.

Immunoisolations of RRC show that distinct transcytotic elements were not detected; rather, recycling receptors and the pIgR were coisolated on the same elements. All immunoisolations were carried out by using 5 μg of RRC protein per 1 mg of antibody-coated magnetic beads. The entire sample from each population of elements was loaded onto the gels. (A) Immunoisolation (ImIs) was carried out by using magnetic beads coated with the anti-pIgR SC166 antibody. (B) The first immunoisolation (ImIs.1) was done by using magnetic beads coated with the anti-LDLR 4A4 antibody. The second immunoisolation (ImIs.2) was done by using magnetic beads coated with the anti-pIgR SC166 antibody. Starting material (SM), bound (B), and unbound (UB) populations of elements were analyzed by Western blotting using either the SC166 antibody or the antibodies against the recycling receptors, LDLR and TfR.