FIG. 1.

In vitro association between PP1α and DP71L. GST beads (lanes 1 and 4) or GST-DP71L beads (lanes 2 and 5) were mixed with bacterial cell lysates containing His-tagged PP1 for 1 h at 4°C (see Materials and Methods). After extensive washing, proteins bound to beads were eluted and analyzed by SDS-polyacrylamide gel electrophoresis and Western blotting with specific antibodies against PP1 (lanes 1 to 3) or 6×His (lanes 4 to 6). Overexpression of 6×His-PP1 as a positive control was detected with both antibodies in lanes 3 and 6, respectively. PP1 was visualized as a pulled-down band from a preloaded GST-DP71L Sepharose matrix (lanes 2 and 5), corresponding to a protein with an apparent molecular mass of ≈36 kDa, but not in the control assays using GST alone (lanes 1 and 4). The positions (in kilodaltons) of protein standards are shown to the right of the gel.