Fig. 5.

4-AP acts through Cavβ3 to increase the plasma membrane expression of Cav1.2 and Cav2.2. (A and B) Original gel images and group data show the differential effect of 0.3 and 3 mM 4-AP on the protein level of Cav1.2 on the plasma membrane in HEK293 cells transfected with α₂δ1 and either Cavβ3 (A) or Cavβ2 (B). (C and D) Representative gel images and summary data illustrate the differential effect of 3 mM 4-AP on the protein level of Cav2.2 on the plasma membrane in cells cotransfected with α₂δ1 and either Cavβ3 (C) or Cavβ2 (D). N = 4 separate experiments in each group. (E) Original gel image and mean data show the effect of 0.3 and 3 mM 4-AP on the protein level of Cav1.2 on the plasma membrane surface in HEK293 cells cotransfected with α2δ1 and Cavβ3 (N = 5 separate experiments in each group). Data from 4-AP–treated samples were first normalized by using the loading (GAPDH) control and then normalized to the control group (without 4-AP). *P < 0.05, **P < 0.01, compared with the control without 4-AP (paired Student’s t test or repeated measures analysis of variance followed by Dunnett’s post hoc test).