A, TsA201 cells were transiently co-transfected with expression vectors encoding 3xFlag-tagged Rem2 and either empty pCDNA3.1+3xHAa (control), HA-tagged CCT-FL or the indicated HA-tagged CCT truncation mutants. Co-immunoprecipitation was performed with anti-HA antibody and Rem2 binding examined by immunoblotting with biotinylated FLAG antibody. Results are representative of three independent experiments. B, TsA201 cells were transiently co-transfected with expression vectors encoding Flag-Rad and either HA-CCT-FL, the indicated HA-tagged CCT truncation mutants, or empty vector. Co-immunoprecipitation analysis was performed as described in A. Results are representative of three independent experiments. C, TsA201 cells were transfected with plasmids expressing Cav1.2(1–1905), β1b and either GFP-Rem or unfused GFP as control. Current was examined using the whole-cell patch clamp configuration in the presence of 30 mM Ba2+.