Figure 7.

UV promotes activation and dimerization of extracellular domain–deleted Ret. Lysates from NIH 3T3 cells transfected with RET-PTC-1 after sham or UV irradiation were analyzed by either Western blotting with anti-Ret antibody (B and C) or in vitro kinase assay after immunoprecipitation with anti-Ret antibody (A, D, and E). SDS-PAGE was done under reducing (A, B, and D) or unreducing (C and E) conditions in 7% (B–E) or 13% (A) polyacrylamide gels. Lanes 1, sham irradiation; lanes 2, 5 min after UV-B irradiation (600 J/m²). M, monomer Ret; D, dimer Ret. All measurements were repeated three times with basically the same results. Representative results are provided.