Effect of increasing expression of CD45-AP on CD45 dimerization in ALST-1 cells. Increasing expression of CD45-AP proportionally reduces CD45 dimerization in ALST-1 cells. (A) ALST-1 cells expressing 3 different levels of HA-CD45-AP (lanes 1-3) and 2 independent control transfectants with empty vector (lanes 4-5) were biosynthetically labeled with 35S-labeled amino acids. The cell lysates were treated with or without DSP and immunoprecipitated with anti-CD45 antibody. The immunoprecipitates were analyzed by SDS-PAGE under nonreducing conditions. Regions scanned for monomers and dimers are indicated by brackets. (B) Cell lysates of ALST-1 transfectants (1 × 106 cells) were immunoblotted with anti-HA antibody. See panel A for description of lanes. (C) ALST-1 transfectants were stained with FITC-conjugated anti-HA antibody and analyzed by flow cytometry.
