FIGURE 1.

Lateral diffusion of a single RyR2 channel in a bilayer in the absence and presence of different concentrations of annexin 12. The position of the RyR2 channel was determined as the 2-dimensional median of the fluo-3 fluorescence response to Ca²⁺ flux through the channel. Twenty data points were recorded at 3-s intervals. In the left panel in the top row, the bilayer was composed of only PE. In the remaining panels bilayers contained 80:20 PE/PS. Annexin 12, at the concentrations indicated below the last four panels was added to the trans chamber before fusion of RyR2 and caused a concentration-dependent decrease in RyR2 diffusion. The dynamics of the diffusion of RyR2 channels and the immobilizing effects of annexin 12 can be appreciated from the movie provided as supplemental material to this report.