Figure 6. cAMP‐dependent I _Ba upregulation is not affected by alanine mutations of S1700 and T1704 in α_1C, or by the Ca_Vβ subunit.

A, mutation S1700A, T1704A, or both to alanine do not alter the extent of cAMP upregulation of Ca_VΔ1821. a, summary of cAMP effect. N = 2 experiments. No statistical significance was found using one‐way ANOVA test. b, representative time course charts of changes in I _Ba following cAMP injection (200 μm). Insets in b show I _Ba current traces in the same cell. B, the presence of Ca_Vβ_2b subunit, or mutations in Ca_Vβ_2b phosphorylation sites, do not alter cAMP regulation. a, an illustration of the constructs used. SH3 and GK are structural modules within the β subunit. Numbers indicate amino acids. b, summary of % increase in I _Ba per cell, following cAMP injection. Oocytes were injected with the following RNAs: 1 ng α_1CΔ1821, α₂δ1 and either Ca_Vβ_2b‐wild‐type (WT), Ca_Vβ_2b‐4A or Ca_Vβ_2b‐CT_trunc, with or without 2.5 ng AKAP15 and 5 ng dCT. α_1CΔ1821 RNA (7 ng) was injected when Ca_Vβ_2b subunit was not present (α_1CΔ1821 and α₂δ1 only). No statistical significance was found using one‐way ANOVA test. c, representative time course charts of I _Ba following cAMP injection (200 μm). Insets show current traces in the same cells.