Figure 4.

Deletion of the β8–β9 loop impairs RyR2 oligomerization. Protein distribution profile of RyR2^WT and RyR2^Δβ8–β9 assessed by sucrose density gradient centrifugation. (A) RyR2^WT and RyR2^Δβ8–β9 were expressed in HEK293 cells, CHAPS-solubilized microsomal membranes were subjected to density-gradient centrifugation and collected sucrose fractions were analysed by western blotting using RyR2 Ab¹⁰⁹³. Microsomes (25 μg, M) were also included to assess protein expression; sucrose concentration as indicated. (B) Cumulative data (n = 4) following densitometry analysis and normalization against the amount of input protein in the microsomes; data are given as mean value ± SEM.