Fig. 1

Protein patterns of distinct plasma membrane microdomains. Purified plasma membranes from isolated rat adipocytes (total plasma membrane) were used for preparation of DIGs by the carbonate method and subsequent sucrose gradient density centrifugation. Pooled fractions 4 and 5 (low buoyant density, hcDIGs), fractions 8 and 9 (high buoyant density, lcDIGs), and fractions 12–15 (carbonate-soluble plasma membrane proteins) were analyzed by SDS-PAGE (identical amounts of protein) and Coomassie blue staining (total protein) or immunoblotting of caveolin-1, GLUT4, and IRβ using chemiluminescent detection. The figure shows representative photographic/chemiluminescent images repeated two times with similar results. Quantitative evaluations from three different adipocyte incubations are given as means (arbitrary units) with total plasma membranes set at 100.