Fig. 5: Bcl-xL Serine (Ser) 14 phosphorylation disrupts its inhibitory interaction with IP3R, enhancing hypertrophic stimuli-induced calcineurin-NFAT signaling.
From: Ser14 phosphorylation of Bcl-xL mediates compensatory cardiac hypertrophy in male mice
a Gene set enrichment analysis plots of calcineurin and calcium regulation pathways enriched in WT compared to knock-in (KI) mouse hearts after 9 hs of TAC. NES, normalized enrichment score. GSEA nominal p value is the statistical significance of the enrichment score by using a phenotype-based permutation test with no adjustment. b The relative NFAT transcriptional activity in response to phenylephrine (PE) with or without 2-APB in cardiomyocytes transfected with adenovirus harboring Bcl-xL-WT or -S14A mutant (n = 6 independently prepared cardiomyocyte preparations/cultures). c Immunoprecipitation assay with anti-IP3R type 2 antibody using WT and KI mouse hearts 1 day after TAC. Repeated three times. d Flag pull-down assay using Flag-Bcl-xL-S14D or -S14A and recombinant GST-IP3R-fragment3, followed by Coomassie Brilliant Blue staining. Right panel shows quantification analysis of immunoprecipitated proteins (GST-IP3R-fragment 3 versus Flag-Bcl-xL-S14D or -S14A) (n = 8 independently prepared cardiomyocyte preparations/cultures, followed by in vitro binding assay). e The relative NFAT transcriptional activity in response to PE with or without synthetic peptide corresponding to the amino acid sequence in IP3R Fragment 3 (n = 6, independently prepared cardiomyocyte preparations/cultures). Two-way ANOVA with Tukey’s multiple comparison test. ****p < 0.0001, ***p < 0.001, **p < 0.01, *p < 0.05, ns not significant. Adjusted p values for (b): 0.0041 (WT, PE vs PE + 2-APB), 0.001 (S14A, Vehicle vs PE), 0.0003 (S14A, Vehicle vs PE + 2-APB). Adjusted p values for (e): 0.0251 (PE, WT vs S14A), 0.0096 (S14A, Vehicle vs PE), 0.0037 (S14A, PE vs PE+Pep). Data are mean ± SEM. Source data are provided as a Source Data file.
