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. 2017 Jan 3;114(3):E416–E425. doi: 10.1073/pnas.1612383114

Fig. S4.

Fig. S4.

(A) IBa traces recorded in HL-1 cells transfected or not with WT or p.R311C Tbx20 by applying the pulse protocol (Top). (B and C) Current density–voltage relationships (B) and steady-state inactivation (C) for IBa recorded in the three experimental groups. (D) Mean densitometric analysis of Cav1.2 levels normalized to total protein. Each point/bar represents the mean ± SEM of n cells or N dishes of cells in each group. *P < 0.05 vs. Tbx20 (-). In these experiments, ICaL was measured using Ba2+ as a charge carrier (15, 18). WT Tbx20 slightly but significantly increased the IBa density (A and B) (n ≥ 9, P < 0.05). Moreover, p.R311C Tbx20 also increased the IBa density similar to Tbx20 WT (n = 7, P > 0.05 vs. Tbx20 WT). However, neither WT nor mutated Tbx20 affected the voltage dependence of activation or inactivation of the channel (C) (Table S3). Western blot analysis in HL-1 cells (D) (Fig. S3) demonstrated that both WT and p.R311C Tbx20 significantly and similarly increase Cav1.2 expression, consistent with the presence of the Tbx20 binding site in the mouse, but not the human, CACNA1C gene promoter (Table S4).