Figure 6. Membrane-targeted Rem^1-265 inhibits I_Ca.

(A) Diagram showing construction of CAAX chimeric proteins and sequences of the K-Ras4B and H-Ras C-terminal and CAAX domains. (B) TsA201 cells were transfected with plasmids expressing GFP-Rem^1-265, GFP-Rem^1-265/KRas4B-CAAX, GFP-Rem^1-265/HRas-CAAX, or GFP-Rem^WT. 72 h after transfection cells were observed by confocal microscopy. Rem^1-265 shows cytosolic localization, but fusion of either of the CAAX tags results in cell peripheral distribution stronger even than that of Rem^WT and consistent with plasma membrane localization. (C) TsA201 cells were transfected with plasmids expressing Ca_V1.2, Ca_Vβ1b, and either GFP-Rem^1-265, GFP-Rem^1-265/KRas4B-CAAX, or GFP-Rem^1-265/HRas-CAAX. Although GFP-Rem^1-265/HRas-CAAX can fully inhibit the activity of this channel complex, GFP-Rem^1-265/KRas4B-CAAX shows only partial inhibition. (D) TsA201 cells were transfected with plasmids expressing Ca_V1.2, Ca_Vβ2a, and either GFP-Rem^1-265/KRas4B-CAAX, GFP-Rem^1-265/HRas-CAAX, or GFP as a control. Although GFP-Rem^1-265/KRas4B-CAAX can fully inhibit the activity of this channel complex, GFP-Rem^1-265/HRas-CAAX shows only partial inhibition. (E) Currents at 5 mV from Figure 6C. A significant difference (p<0.05) between treatments is denoted by asterisks. (F) Currents at 5 mV from Figure 6D. A significant difference (p<0.05) between treatments is denoted by asterisks.