Figure 1.

Components of MAP kinase module in caveolae. Normal human fibroblasts were grown as described. (A) Caveolae were purified and immunoblotted with the indicated antibody. (B and C) Membranes were attached to Formvar/carbon-coated electron microscope grids and labeled with either monoclonal anti-erk2 IgG (10-nm gold) alone (B) or monoclonal anti-erk2 IgG (10-nm gold) plus polyclonal anti-PDGF receptor IgG (5-nm gold) (C). In C, the small arrows point to caveolae containing PDGF receptors and the large arrows point to caveolae containing erk2. The asterisks indicate clathrin-coated pits. (Bars = 0.2 μm.)