β-Adrenergic Stimulation Induces Histone Deacetylase 5 (HDAC5) Nuclear Accumulation in Cardiomyocytes by B55α-PP2A-Mediated Dephosphorylation.

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Weeks, KL; Ranieri, A; Karaś, A; Bernardo, BC; Ashcroft, AS; Molenaar, C; McMullen, JR; Avkiran, MDate
2017-03-25Source Title
Journal of the American Heart AssociationPublisher
Ovid Technologies (Wolters Kluwer Health)University of Melbourne Author/s
Bernardo, BiancaAffiliation
Paediatrics (RCH)Metadata
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Weeks, K. L., Ranieri, A., Karaś, A., Bernardo, B. C., Ashcroft, A. S., Molenaar, C., McMullen, J. R. & Avkiran, M. (2017). β-Adrenergic Stimulation Induces Histone Deacetylase 5 (HDAC5) Nuclear Accumulation in Cardiomyocytes by B55α-PP2A-Mediated Dephosphorylation.. J Am Heart Assoc, 6 (4), https://doi.org/10.1161/JAHA.116.004861.Access Status
Open AccessOpen Access at PMC
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5533001Abstract
BACKGROUND: Class IIa histone deacetylase (HDAC) isoforms such as HDAC5 are critical signal-responsive repressors of maladaptive cardiomyocyte hypertrophy, through nuclear interactions with transcription factors including myocyte enhancer factor-2. β-Adrenoceptor (β-AR) stimulation, a signal of fundamental importance in regulating cardiac function, has been proposed to induce both phosphorylation-independent nuclear export and phosphorylation-dependent nuclear accumulation of cardiomyocyte HDAC5. The relative importance of phosphorylation at Ser259/Ser498 versus Ser279 in HDAC5 regulation is also controversial. We aimed to determine the impact of β-AR stimulation on the phosphorylation, localization, and function of cardiomyocyte HDAC5 and delineate underlying molecular mechanisms. METHODS AND RESULTS: A novel 3-dimensional confocal microscopy method that objectively quantifies the whole-cell nuclear/cytoplasmic distribution of green fluorescent protein tagged HDAC5 revealed the β-AR agonist isoproterenol to induce β1-AR-mediated and protein kinase A-dependent HDAC5 nuclear accumulation in adult rat cardiomyocytes, which was accompanied by dephosphorylation at Ser259/279/498. Mutation of Ser259/Ser498 to Ala promoted HDAC5 nuclear accumulation and myocyte enhancer factor-2 inhibition, whereas Ser279 ablation had no such effect and did not block isoproterenol-induced nuclear accumulation. Inhibition of the Ser/Thr phosphatase PP2A blocked isoproterenol-induced HDAC5 dephosphorylation. Co-immunoprecipitation revealed a specific interaction of HDAC5 with the PP2A targeting subunit B55α, as well as catalytic and scaffolding subunits, which increased >3-fold with isoproterenol. Knockdown of B55α in neonatal cardiomyocytes attenuated isoproterenol-induced HDAC5 dephosphorylation. CONCLUSIONS: β-AR stimulation induces HDAC5 nuclear accumulation in cardiomyocytes by a mechanism that is protein kinase A-dependent but requires B55α-PP2A-mediated dephosphorylation of Ser259/Ser498 rather than protein kinase A-mediated phosphorylation of Ser279.
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