Fig. 1.

Oleate uptake by intestinal brush border membranes is caveolin-1 dependent and is in detergent resistant membranes. A. BB from WT (WT) and KO (KO) mice were prepared and incubated with ³H-oleate bound to albumin (Methods). The percentage of ³H-oleate taken up by both sets of BB is shown on the ordinate. The BB from both mouse genotypes were depleted of cholesterol (WT-dep) and (KO-dep) (Methods) and tested for albumin bound ³H-oleate uptake. The percentage of ³H-oleate taken up by both BB preparations is shown on the ordinate. The data are the mean ± SEM (N = 4). The p value tests the differences between the means of the native WT and KO BB preparations. B. The distribution of oleate in an OptiPrep gradient when incubated with (WT or KO) BB or without BB. ³H-oleate was incubated either with 1 mg prot WT-BB (closed squares), KO-BB (open circles), or by itself (open squares) at 37°C for 30 min. The brush borders were washed twice, re-isolated by centrifugation, and dissolved in 1% Triton X-100. The resulting mixture was placed at the bottom of an OptiPrep gradient and centrifuged for 20h (Methods). The gradient was resolved, 1 ml fractions collected (9 ml total volume), and the total ³H-oleate-dpm determined. C. Immunoblots (50 (µg prot) for caveolin-1, CD36, intestinal alkaline phosphatase (IAP), and clathrin are shown for each OptiPrep fraction. BB is the brush border fraction. E is empty lane.