Figure 5. RSK3 anchoring disruption attenuates pressure overload-induced cardiac hypertrophy and heart failure.

A, mAKAP domain structure showing sites for binding partners that have been finely mapped and RBD and PBD peptides used in this project.^{4, 14, 27, 41-45} Muscle mAKAPβ is identical to neuronal mAKAPα but starting at residue 245. AC5 - adenylyl cyclase 5; MEF2 - myocyte enhancer factor-2; PLCε – phospholipase Cε; RyR – ryanodine receptor; CaN – calcineurin. B, Adult rat ventricular myocytes infected with adenovirus expressing myc-GFP or myc-GFP-RBD were cultured for 24 hours +/− 20 μmol/L phenylephrine (PE). n = 3. Cf. Figure XII in Data Supplement. C, Myocytes as in B were assayed by immunocytochemistry and morphometry. Anti-actinin – red, GFP and GFP-RBD in green, nuclei in blue. Bar - 25 μm. Bars and colored symbols indicate average mean and means of independent experiments using different myocyte preparations, respectively. n = 3. * vs. myc-GFP + PE; ^† vs. myc-GFP + no drug. D, myc-GFP-RBD (AAV9.RBD) and myc-GFP (AAV9.GFP) were expressed in mice using AAV9 and the cardiac myocyte-specific chicken troponin T promoter.²⁴ E, Timeline for AAV9.RBD prevention studies shown in F-J. F, Co-immunoprecipitation of mAKAPβ-RSK3 complexes using heart extracts obtained from adult RSK3^−/− and AAV9.RBD and AAV9.GFP injected mice and using a pan-RSK antibody (C-20). n: RSK3^−/− - 5, AAV mice - 8. G, left ventricular mass (normalized by body weight) based upon M-mode echocardiography 2 weeks post-TAC. n = 8-27. H, Wheat-germ agglutinin staining 2 weeks post-TAC. Bar - 50 μm. n = 3-6. I, left ventricular volume in systole 16-weeks post-TAC. J, gravimetric analysis 16-weeks post-TAC. I,J: n = 11-24. G-J: Bars indicate mean +/− s.e.m. * vs. GFP-TAC cohort; ^† vs. Sham treatment for same AAV. Data for C and G-J analyzed by matched two-way ANOVA and Tukey post-hoc testing. *,^† p < 0.05; **,^†† p < 0.01; ***,^††† p < 0.001.