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Dynamic nucleocytoplasmic shuttling of class IIa histone deacetylases (HDACs) is a fundamental mechanism regulating gene transcription. Recent studies have identified several protein kinases that phosphorylate HDAC5, leading to its exportation from the nucleus. However, the negative regulatory mechanisms for HDAC5 nuclear exclusion remain largely unknown. Here we show that cAMP-activated protein kinase A (PKA) specifically phosphorylates HDAC5 and prevents its export from the nucleus, leading to suppression of gene transcription. PKA interacts directly with HDAC5 and phosphorylates HDAC5 at serine 280, an evolutionarily conserved site. Phosphorylation of HDAC5 by PKA interrupts the association of HDAC5 with protein chaperone 14-3-3 and hence inhibits stress signal-induced nuclear export of HDAC5. An HDAC5 mutant that mimics PKA-dependent phosphorylation localizes in the nucleus and acts as a dominant inhibitor for myocyte enhancer factor 2 transcriptional activity. Molecular manipulations of HDAC5 show that PKA-phosphorylated HDAC5 inhibits cardiac fetal gene expression and cardiomyocyte hypertrophy. Our findings identify HDAC5 as a substrate of PKA and reveal a cAMP/PKA-dependent pathway that controls HDAC5 nucleocytoplasmic shuttling and represses gene transcription. This pathway may represent a mechanism by which cAMP/PKA signaling modulates a wide range of biological functions and human diseases such as cardiomyopathy. [ABSTRACT FROM AUTHOR]

Vascular endothelial growth factor (VEGF) is essential for normal and pathological angiogenesis. However, the signaling pathways linked to gene regulation in VEG F-induced angiogenesis are not fully understood. Here we demonstrate a critical role of protein kinase D (PKD) and histone deacetylase 5 (HDAC5) in VEGF-induced gene expression and angiogenesis. We found that VEGF stimulated HDAC5 phosphorylation and nuclear export in endothelial cells through a VEGF receptor 2-phospholipase Cγ-protein kinase C-PKD-dependent pathway. We further showed that the PKD-HDAC5 pathway mediated myocyte enhancer factor-2 transcriptional activation and a specific subset of gene expression in response to VEGF, including NR4A1, an orphan nuclear receptor involved in angiogenesis. Specifically, inhibition of PKD by overexpression of the PKD kinase-negative mutant prevents VEGF-induced HDAC5 phosphorylation and nuclear export as well as NR4A1 induction. Moreover, a mutant of HDAC5 specifically deficient in PKD-dependent phosphorylation inhibited VEGF-mediated NR4A1 expression, endothelial cell migration, and in vitro angiogenesis. These findings suggest that the PKD-HDAC5 pathway plays an important role in VEGF regulation of gene transcription and angiogenesis. [ABSTRACT FROM AUTHOR]

Angiotensin II (Ang II) induces the phenotypic modulation and hypertrophy of vascular smooth muscle cells (VSMCs), which is implicated in the pathogenesis of hypertension and atherosclerosis. Here we established a novel role of histone deacetylases 5 (HDAC5) in Ang II-induced VSMC hypertrophy. We showed that Ang II rapidly stimulated phosphorylation of HDAC5 (p-HDAC5) on Ser259/498 sites in a time- and dose- dependent manner in rat aortic VSMCs. Ang II receptor 1 mediated p-HDAC5. Protein kinase C (PKC) inhibitors, GF109203X and Gö6983, inhibited p-HDAC5. Using pharmacological inhibitor, siRNA and adenovirus encoding kinase-negative mutant of protein kinase D (PKD) demonstrated that PKD was essential for p-HDAC5 by Ang II. Moreover, we showed that Ang II stimulated HDAC5 nuclear export, which was dependent on its phosphorylation via PKC/PKD pathway, because HDAC5 nuclear export was abolished by inhibiting PKC and PKD and by infection of adenovirus encoding HDAC5 S259/498A mutant. Furthermore, both PKD inhibition and HDAC5 S259/498A mutant blocked Ang II-induced myocyte enhancer factor 2 (MEF2) transcriptional activation. Importantly, Ang II promoted VSMC protein synthesis in PKD and HDAC5-dependent manner. Our findings reveal for the first time that PKD and HDAC5 play a key role in Ang II-induced VSMC hypertrophy, and suggest that PKD and HDAC5 may emerge as potential targets for cardiovascular diseases. [ABSTRACT FROM AUTHOR]