FIGURE 6. S100A1 competes with CaM for binding to intact RyR1 in isolated SR vesicles.
A, S100A1 competes RyR1 away from agarose-linked CaM beads at high Ca2+ concentrations, as visualized by a decreased RyR1 band intensity in an anti-RyR Western blot. Each bar graph is the average of at least three images. At the bottom are representative bands from a single blot. Free CaM, a positive control, also competes RyR away from CaM-linked beads in the same protein concentration range. B, S100A1 and CaM compete RyR1 from CaM beads at low (100 nM) Ca2+ concentrations similar to those established for resting skeletal muscle (65).