Fig. 4: α-Tubulin acetylation is decreased through SRF-mediated expression of ATAT1 in cells, and cardiac tissue expressing cardiomyopathy-causing mutant A-type lamins.

a Schematic view of the enzymes responsible for acetylation and deacetylation of α-tubulin. b Experimental protocol for measuring SRF transcriptional activity based on ATAT1 expression by luciferase assay. c Box plot showing the quantification of luciferase activity after C2-WT and C2-H222P cells were transfected with the construction described in (b) (n = 3 independent experiments; whiskers min to max, line in the middle of the box is plotted at the median). d Bar graph showing mRNA relative expression of Srf, Acta2, and Atat1 in C2C12 transfected with plasmids expressing inactive MRTF-A (MRTFΔ100), WT MRTF-A (MRTF), or constitutively active SRF (SRF-VP16) (n = 3 independent experiments, mean ± SD). e Left: immunoblot showing α-TAT1 and α-tubulin expression in hearts of 6-month-old male WT and Lmna^{p.H222P/H222P} (H222P) mice. Right: bar graph showing the quantification of α-TAT1 (n = 3 WT and n = 5 H222P, mean ± SD). f–j Top left: immunoblot showing expression of acetylated and total α-tubulin, top right: bar graph showing the quantification of acetylated α-tubulin normalized to total α-tubulin (f) in the hearts of 3-month-old male WT and Lmna^{p.H222P/H222P} (H222P) mice (n = 3 mice per condition, mean ± SD). g in adult cardiomyocytes isolated from 3-month-old male WT and Lmna^{p.H222P/H222P} (H222P) mice (n = 3 mice per condition, mean ± SD). Bottom: representative immunofluorescence staining of acetylated α-tubulin (h) in explanted heart tissue from control individuals (n = 3) and patients carrying LMNA point mutations (n = 5) (mean ± SD). i in cardiomyocytes derived from iPS cells from a control (WT), a patient carrying LMNA p.R190W mutation (upper panel) and a patient carrying LMNA p.H222P mutation (lower panel). Bottom: representative immunofluorescence staining of acetylated α-tubulin in cardiomyocytes derived from iPS WT and H222P. α-Actinin is shown as cardiomyocyte differentiation marker. j In C2-WT and C2-H222P cells (n = 3 independent experiments, mean ± SD). Bottom: representative immunofluorescence staining of acetylated α-tubulin. k Immunoblot showing expression of HDAC6 in hearts of 6-month-old male WT mice and Lmna^{p.H222P/H222P} (H222P) mice (n = 3 mice per condition) as well as in C2-WT and C2-H222P cells (a representative of three independent repeats is shown). Statistics: for c, e–h, and j, unpaired two-tailed t-test; for d, one-way ANOVA followed by Tukey’s multiple comparison test. Source data are provided as a Source Data file. For b, parts of the figure were drawn by using pictures from Servier Medical Art. Servier Medical Art by Servier is licensed under a Creative Commons Attribution 3.0 Unported License (https://creativecommons.org/licenses/by/3.0/).