Fig. 5. The trimer Pnr-Chip-Tou can exist in living cells. The ternary complex is revealed by double-immunoprecipitation of protein extracts made from transfected Cos cells. (A) Immunoblot of a representative set of protein extracts. The transfected expression vectors are shown at the top. The asterisk denotes an artifactual band. (B) Double-immunoprecipitation of the protein extracts described in panel A. The M2 (IP 1) and B10 (IP 2) mouse antibodies are used to immunoprecipitate the flagged TouA domain (F.TouA) and the tagged full-lenght Chip (B10.Chip), respectively. They are shown on the left of the panels. After immunoprecipitation with the M2 antibody, the selected proteins were recovered by elution with the Flag peptide (IP 1 mAB M2+Elution). The antibodies used to reveal the blots are indicated at the bottom of the panels. Pnr, the F-TouA domain and the B10-Chip are recognized by the 2B8, the M2 and the B10 antibody, respectively. The locations of the proteins, including the IgG(H) of the B10 antibody, are indicated by arrows.