HDAC3-dependent Reversible Lysine Acetylation of Cardiac Myosin Heavy Chain Isoforms Modulates Their Enzymatic and Motor Activity

Abstract

Reversible lysine acetylation is a widespread post-translational modification controlling the activity of proteins in different subcellular compartments. We previously demonstrated that a class II histone deacetylase (HDAC), HDAC4, and a histone acetyltransferase, PCAF, associate with cardiac sarcomeres, and a class I and II HDAC inhibitor, trichostatin A, enhances contractile activity of myofilaments. In this study, we show that a class I HDAC, HDAC3, is also present at cardiac sarcomeres. By immunohistochemical and electron microscopic analyses, we found that HDAC3 was localized to the A band of sarcomeres and was capable of deacetylating myosin heavy chain (MHC) isoforms. The motor domains of both cardiac ␣-and ␤-MHC isoforms were found to be reversibly acetylated. Biomechanical studies revealed that lysine acetylation significantly decreased the K m for the actin-activated ATPase activity of both ␣-and ␤-MHC isoforms. By an in vitro motility assay, we found that lysine acetylation increased the actin sliding velocity of ␣-myosin by 20% and ␤-myosin by 36%, compared to their respective non-acetylated isoforms. Moreover, myosin acetylation was found to be sensitive to cardiac stress. During induction of hypertrophy, myosin isoform acetylation increased progressively with duration of stress stimuli, independent of isoform shift, suggesting that lysine acetylation of myosin could be an early response of myofilaments to increase contractile performance of the heart. These studies provide the first evidence for localization of HDAC3 at myofilaments and uncover a novel mechanism modulating the motor activity of cardiac MHC isoforms.

Mammalian plasma membrane proteins as potential biomarkers and drug targets

“…In an interesting model, Jackson [101] discussed the possible role of N-terminal acetylation of GTPases, and subsequent association of this enzyme with membrane, a process that further influences membrane trafficking and organelle structure in eukaryotic cells. Cytoskeletal proteins such as cytokeratins [102], tubulin [103][104][105] and myosin [99,106] can also be acetylated, and this PTM can influence their association with the plasma membrane. Casale et al [103] and Santander et al [104] have shown that the brain plasma membrane Na 1 , K 1 -ATP-ase is inhibited by acetylated tubulin.…”

Non-sirtuin histone deacetylases in the control of cardiac aging

“…However, it is important to emphasize that this is an oversimplification. For example, HDAC3 has also been found at the plasma membrane, where it regulates Src tyrosine kinase activity [21], and in cardiomyocytes HDAC3 has been shown to co-localize with sarcomeres [22]. …”

Epigenetic Mechanisms in Heart Failure Pathogenesis

“…Taken together, these studies support that excessive activation of p300 acetyltransferase is involved in pathologic cardiac hypertrophy and inhibition of p300 might be a potential therapeutic strategy in HF. While p300 has been the most extensively studied, other proteins with Kac ”writing” capabilities such as CBP and PCAF are also emerging as important regulators of cardiac remodeling 85 .…”

“…A number of these HDACs have been studied in the context of cardiac remodeling and HF pathogenesis using genetically modified mouse models and pharmacological inhibitors 46, 85, 87-111 (Table 2). Of these, members of HDAC classes I, IIa, and III have been most extensively studied while very little is known about class IIb and IV HDACs.…”

“…The apicidin derivative API-D, which inhibits HDACs 1-3 (albeit with modest in vitro activity against HDAC6) 115 has been shown to have beneficial effects in rodent models of pressure overload 120 . Future work using next-generation inhibitors with better target-specificity will be required 119 to elucidate the therapeutic potential of HDAC modulation in the heart 46, 85, 87-111 (Table 2). …”