The caveolar coat complex has a defined stoichiometry.

<p>(A) Cells expressing GFP, cavin-1-GFP, cavin-2-GFP, or cavin-3-GFP were cross-linked and lysed in 1% Triton X-100/1% octyl glucoside, followed by immuno-isolation of the complexes using anti-GFP antibodies. Eluted proteins were separated by SDS-PAGE and stained with Sypro Ruby. (B–E) Quantification of the relative molar ratios between cavin 1, 2, -3-GFP, cavin 1, cavin 3, and caveolins in the caveolar coat complex. Shown are the means +/− standard error determined from 6–8 independent experiments. Student <i>t</i> test was used to determine significant differences between samples. (F) Confocal microscopy to show levels of cavin 1, detected by indirect immunofluorescence, and cavin-3-GFP, in cells overexpressing high levels of cavin-2-mCherry. Cavin-3-GFP is stably transfected in these cells. Cavin-2-mCherry is shown in blue in the overlay panel, and the same cells are outlined in the other panels. (G) Quantification of fluorescence intensity from cells as in (F). Cavin 1 and cavin-3-GFP intensities are normalised so that the mean signal in cells without cavin-2-mCherry is always 1. Data from a single experiment are shown, each data point representing a single cell. The experiment was repeated three times with equivalent results. (H and I) These represent essentially the same experiments as in (F) and (G), except that here the effect of overexpressing cavin-3-mCherry in cells stably transfected with cavin-2-GFP was examined.