Fig. 2
The β1b-subunit increases the amount of CaV channels at the plasma membrane. a Co-localization analysis of HEK-293 cells expressing the α1-subunit of CaV1.2, CaV3.1, CaV3.2 and CaV3.3 fused to GFP, in the absence (-β1b) and presence (+β1b) of the β1b-subunit. Representative confocal microscopy images of cells expressing the respective CaV shown in green (left panels) and the plasma membrane marker FM4-64 (shown in red, middle panel). The co-localization between the CaV α1-subunit and the FM4-64 (in yellow) is shown in Merge panels. The plots to the right show the total pixels of colocalization between the green channel (CaV) and the red channel (FM-464), with the corresponding Pearson’s correlation coefficient (R) for each experimental condition. b The FRET between the GFP in each CaV channel and the blue fluorescent protein in the β1b-subunit. Notice that FRET is observed only between CaV1.2 (HVA channel) and β1b, but not with the other 3 CaV channels (CaV3.1, CaV3.2 and CaV3.3). High and low FRET was calculated pixel-by-pixel and the image shows in pseudo color FRET intensities. The number of cells analyzed for both colocalization and FRET panels were as follows: CaV1.2, 65; CaV3.1, 35; CaV3.2, 48; and CaV3.3, 32. The cells were obtained from 4 to 13 independent experiments. Scale bar: 10 μm