Association of PI3K with lipid bodies independent of caveolae in endothelial cells.

Endothelial cells were subjected to subcellular fractionation as described in “Materials and Methods.” Lipid body fractions were identified microscopically by their content of Nile red staining lipid bodies. Fractions were assayed for LDH and sulfatase C activities as cytosolic and microsomal markers, respectively (A). Equal amounts of protein (20 μg) concentrated from each subcellular fraction and from control cell lysates were electrophoresed and immunoblotted with anti-caveolin mAb (B) or anti-PI3K p85 mAb (C). Similar results were obtained from 3 independent experiments.