Fig. 5. PINCH and ILK co-precipitate and colocalize at integrin-rich sites in Drosophila embryos. (A-C) An optical section of a stage 16 embryo showing the localization of the indicated proteins. (A) PINCH immunoreactivity. (B) ILK::GFP. (C) Merged image of A,B. (D) Native immunoprecipitation of PINCH and associated proteins from Drosophila embryonic lysates. Lanes 1-4 represent different immunoprecipitation experiments, run out on an SDS-PAGE gel. The resulting blot was probed with the antisera indicated on the right-hand side. Immunoprecipitations with the PINCH preimmune serum (PI) serve as negative controls, while PINCH immunocomplexes were isolated with the affinity-purified PINCH antiserum (anti-Pin). (E,F) ILK::GFP distribution in a wild-type (E) and stck¹⁷ maternal/zygotic mutant (F) stage 16 embryo. The ILK fusion protein is still concentrated at the muscle-attachment sites in the stck mutant embryo (arrows in F).