The Experts below are selected from a list of 42783 Experts worldwide ranked by ideXlab platform
Charles J. Lowenstein - One of the best experts on this subject based on the ideXlab platform.
-
histone deacetylase isoforms regulate innate immune responses by deacetylating mitogen activated protein kinase phosphatase 1
Journal of Leukocyte Biology, 2014Co-Authors: Youngtae Jeong, Ronghui Du, Charles J. LowensteinAbstract:The MAPK pathway mediates TLR signaling during innate immune responses. We discovered previously that MKP-1 is acetylated, enhancing its interaction with its MAPK substrates and deactivating TLR signaling. As HDACs modulate inflammation by deacetylating histone and nonhistone proteins, we hypothesized that HDACs may regulate LPS-induced inflammation by deacetylating MKP-1. We found that mouse macrophages expressed a subset of HDAC isoforms (HDAC1, HDAC2, and HDAC3), which all interacted with MKP-1. Genetic silencing or pharmacologic inhibition of HDAC1, -2, and -3 increased MKP-1 acetylation in cells. Furthermore, knockdown or pharmacologic inhibition of HDAC1, -2, and -3 decreased LPS-induced phosphorylation of the MAPK member p38. Also, pharmacologic inhibition of HDAC did not decrease MAPK signaling in MKP-1 null cells. Finally, inhibition of HDAC1, -2, and -3 decreased LPS-induced expression of TNF, IL-1 , iNOS (NOS2), and nitrite synthesis. Taken together, our results show that HDAC1, -2, and -3 deacetylate MKP-1 and that this post-translational modification increases MAPK signaling and innate immune signaling. Thus, HDAC1, -2, and -3 isoforms are potential therapeutic targets in inflammatory diseases. J. Leukoc. Biol. 95: 000–000; 2014.
-
histone deacetylase isoforms regulate innate immune responses by deacetylating mitogen activated protein kinase phosphatase 1
Journal of Leukocyte Biology, 2014Co-Authors: Youngtae Jeong, Xiaolei Zhu, Shasha Yin, Jian Wang, Hengmi Cui, Wangsen Cao, Charles J. LowensteinAbstract:The MAPK pathway mediates TLR signaling during innate immune responses. We discovered previously that MKP-1 is acetylated, enhancing its interaction with its MAPK substrates and deactivating TLR signaling. As HDACs modulate inflammation by deacetylating histone and nonhistone proteins, we hypothesized that HDACs may regulate LPS-induced inflammation by deacetylating MKP-1. We found that mouse macrophages expressed a subset of HDAC isoforms (HDAC1, HDAC2, and HDAC3), which all interacted with MKP-1. Genetic silencing or pharmacologic inhibition of HDAC1, -2, and -3 increased MKP-1 acetylation in cells. Furthermore, knockdown or pharmacologic inhibition of HDAC1, -2, and -3 decreased LPS-induced phosphorylation of the MAPK member p38. Also, pharmacologic inhibition of HDAC did not decrease MAPK signaling in MKP-1 null cells. Finally, inhibition of HDAC1, -2, and -3 decreased LPS-induced expression of TNF-α, IL-1β, iNOS (NOS2), and nitrite synthesis. Taken together, our results show that HDAC1, -2, and -3 deacetylate MKP-1 and that this post-translational modification increases MAPK signaling and innate immune signaling. Thus, HDAC1, -2, and -3 isoforms are potential therapeutic targets in inflammatory diseases.
Edward Seto - One of the best experts on this subject based on the ideXlab platform.
-
histone deacetylase 3 interacts with and deacetylates myocyte enhancer factor 2
Molecular and Cellular Biology, 2007Co-Authors: Serge Grégoire, Edward Seto, Lin Xiao, Xiaohong Zhang, Minghong Xu, Jiarong Li, Jiemin Wong, Xiang-jiao YangAbstract:The myocyte enhancer factor 2 (MEF2) family of transcription factors is not only important for controlling gene expression in normal cellular programs, like muscle differentiation, T-cell apoptosis, neuronal survival, and synaptic differentiation, but has also been linked to cardiac hypertrophy and other pathological conditions. Lysine acetylation has been shown to modulate MEF2 function, but it is not so clear which deacetylase(s) is involved. We report here that treatment of HEK293 cells with trichostatin A or nicotinamide upregulated MEF2D acetylation, suggesting that different deacetylases catalyze the deacetylation. Related to the trichostatin A sensitivity, histone deacetylase 4 (HDAC4) and HDAC5, two known partners of MEF2, exhibited little deacetylase activity towards MEF2D. In contrast, HDAC3 efficiently deacetylated MEF2D in vitro and in vivo. This was specific, since HDAC1, HDAC2, and HDAC8 failed to do so. While HDAC4, HDAC5, HDAC7, and HDAC9 are known to recognize primarily the MEF2-specific domain, we found that HDAC3 interacts directly with the MADS box. In addition, HDAC3 associated with the acetyltransferases p300 and p300/CBP-associated factor (PCAF) to reverse autoacetylation. Furthermore, the nuclear receptor corepressor SMRT (silencing mediator of retinoid acid and thyroid hormone receptor) stimulated the deacetylase activity of HDAC3 towards MEF2 and PCAF. Supporting the physical interaction and deacetylase activity, HDAC3 repressed MEF2-dependent transcription and inhibited myogenesis. These results reveal an unexpected role for HDAC3 and suggest a novel pathway through which MEF2 activity is controlled in vivo.
-
Negative Regulation of Histone Deacetylase 8 Activity by Cyclic AMP-Dependent Protein Kinase A
Molecular and cellular biology, 2004Co-Authors: Heehyoung Lee, Natalie Rezai-zadeh, Edward SetoAbstract:In eukaryotes, genomic DNA is wrapped tightly around core histones to form nucleosomes, the fundamental building blocks of chromatin. Nucleosomes, once regarded as inert structural particles, are now considered integral and dynamic components of the machineries responsible for gene regulation. Many different enzymes and protein complexes are known to bring about changes in the state of chromatin by numerous mechanisms, with resultant effects on gene expression. One class of complexes alters DNA packaging (remodels chromatin) in an ATP-dependent manner (4, 29). Another class of chromatin-altering factors acts by covalently modifying histone proteins (5). These modifications include acetylation, phosphorylation, methylation, ubiquitination, and ADP-ribosylation. The best-characterized posttranslational histone modification is acetylation, which is catalyzed by histone acetyltransferase (HAT) enzymes. Histone acetylation is a reversible process that is regulated by the opposing activities of HATs and histone deacetylases (HDACs). Generally, hyperacetylation of histones results in transcriptional activation whereas deacetylation correlates with transcriptional silencing. Consistent with this generalization, transcriptional activators are often associated with HAT activity whereas HDACs frequently form complexes with transcriptional repressors (24). Therefore, these two regulatory processes work in harmony to achieve appropriate levels of gene expression. Several oncogenes and tumor suppressors (pRb, BRCA-1, BRCA-2, PML-RAR, and a zinc finger protein mutated in leukemia) have been shown to be associated with HATs or HDACs (41). HDAC proteins are vital regulators of fundamental cellular events, including cell cycle progression, differentiation, and tumorigenesis (37, 45). A small-molecule inhibitor of HDAC, trichostatin A (TSA), arrests mammalian cells in both G1 and G2 (31, 44), while overexpression of HDAC1 in mouse cells reduces their growth rate by lengthening the duration of G2 and M (3). TSA induces terminal differentiation of mouse erythroleukemia cells and apoptosis of lymphoid and colorectal cancer cells. In addition, TSA treatment of cells expressing the PML zinc finger protein derepresses transcription and allows cells to differentiate normally (18). With this precedent, HDAC inhibitors are being actively explored as potential agents for the treatment of certain forms of cancer (22, 23, 27). The human HDACs are organized into three different classes based on their similarity to yeast HDAC proteins (37, 45). Class I enzymes are ubiquitously expressed and include HDAC1, -2, -3, and -8, which are homologous to the yeast RPD3 protein. Class II includes HDAC4, -5, -6, -7, -9, and -10, which are similar to yeast HDA1 and are expressed in a tissue-specific manner. The Sir2-like class III HDACs, including SIRT1 to -7, require NAD+ for enzymatic activity. The most recent addition to the human HDAC family, HDAC11, uniquely shares sequence homology with the catalytic regions of both class I and II HDAC enzymes (15). By far, the most frequently studied and best-characterized human HDACs are HDAC1 and HDAC2. Early studies elegantly demonstrated that HDAC1 and HDAC2 were associated with proteins that modulate their enzymatic activity and their recruitment to genomic regions. Three large multisubunit protein complexes, called Sin3, NuRD/Mi2, and CoREST, contain HDAC1 and HDAC2 (1, 17, 21, 25, 30, 38, 42, 46-48). In addition to complex formation, recent studies have revealed that the activity of class I HDACs is regulated by posttranslational modifications. For example, HDAC1 is a substrate for SUMO-1 (small ubiquitin-related modifier 1), and mutations of the target residues decrease transcriptional repression without affecting the ability of HDAC1 to associate with mSin3 (10). In addition, like those of many class II HDACs, the actions of HDAC1 and HDAC2 are regulated by phosphorylation. Phosphorylation of HDAC1 by protein kinase CK2 alters HDAC1's enzymatic activity and its capacity to form protein complexes (7, 13, 33). Similarly, phosphorylation of HDAC2 by protein kinase CK2 is essential for HDAC2's deacetylase activity and its association with mSin3, Mi2, Sp1, and Sp3 (36, 39). Our previous studies showed that, like HDAC1 and HDAC2, HDAC3 also is phosphorylated by protein kinase CK2 (39). Surprisingly, unlike other members of the class I HDAC family, HDAC8 is not phosphorylated by protein kinase CK2 (39). However, it is possible that kinases other than protein kinase CK2 phosphorylate HDAC8 and modulate its activity. A complete understanding of how phosphorylation regulates the actions of class I HDACs requires a thorough determination of whether HDAC8 is a phosphoprotein and, if so, what kinase is responsible and what the functional consequences are. HDAC8 cDNA was identified initially by three independent groups using sequence homology database searches with class I HDAC proteins (6, 20, 40). The HDAC8 gene encodes a 377-amino-acid protein with a predicted molecular mass of 45 kDa and is located on the X chromosome at position q21.2-q21.3 or q13 (6, 40). Protein sequence comparisons of HDAC8 reveal a 37% similarity to HDAC1. In Northern blot analyses, the size of HDAC8 mRNA is between 1.7 and 2.4 kb, and HDAC8 mRNA is expressed in multiple human organs, including the liver, heart, brain, lung, pancreas, placenta, prostate, and kidney. Consistent with the presence of a stretch of basic residues that could serve as a nuclear localization signal, HDAC8 is predominantly located in the nucleus. A recent report suggests that the inv (16) fusion protein specifically associates with HDAC8 (11). Although sequence analysis of HDAC8 revealed consensus phosphorylation sites for protein kinase A (PKA) and protein kinase CK2, our previous studies showed that HDAC8 was not phosphorylated by protein kinase CK2 in vitro (39). In the present study, we show that HDAC8 is phosphorylated instead by PKA both in vitro and in vivo. Most interestingly, phosphorylation of HDAC8 by PKA inhibits its deacetylase activity, which results in the hyperacetylation of histones H3 and H4. Thus, our findings uncover a novel mechanism of class I HDAC regulation.
-
functional domains of histone deacetylase 3
Journal of Biological Chemistry, 2002Co-Authors: Wenming Yang, Shihchang Tsai, Gyorgy Fejer, Edward SetoAbstract:Abstract Post-translational modifications of histones, in general, and acetylation/deacetylation, in particular, can dramatically alter gene expression in eukaryotic cells. In humans, four highly homologous class I HDAC enzymes (HDAC1, HDAC2, HDAC3, and HDAC8) have been identified to date. Although HDAC3 shares some structural and functional similarities with other class I HDACs, it exists in multisubunit complexes separate and different from other known HDAC complexes, implying that individual HDACs might function in a distinct manner. In this current study, to understand further the cellular function of HDAC3 and to uncover possible unique roles this protein may have in gene regulation, we performed a detailed analysis of HDAC3 using deletion mutations. Surprisingly, we found that the non-conserved C-terminal region of HDAC3 is required for both deacetylase and transcriptional repression activity. In addition, we discovered that the central portion of the HDAC3 protein possesses a nuclear export signal, whereas the C-terminal part of HDAC3 contributes to the protein's localization in the nucleus. Finally, we found that HDAC3 forms oligomers in vitro and in vivo and that the N-terminal portion of HDAC3 is necessary for this property. These data indicate that HDAC3 comprises separate, non-overlapping domains that contribute to the unique properties and function of this protein.
-
the histone deacetylase 3 complex contains nuclear receptor corepressors
Proceedings of the National Academy of Sciences of the United States of America, 2000Co-Authors: Valentina Perissi, Lena Staszewski, Wenming Yang, Anna Krones, Christopher K Glass, Michael G Rosenfeld, Edward SetoAbstract:Acetylation and deacetylation of nucleosomal histones have profound effects on gene transcription in all eukaryotes. In humans, three highly homologous class I and four class II histone deacetylase (HDAC) enzymes have been identified to date. The class I deacetylases HDAC1 and HDAC2 are components of multisubunit complexes, one of which could associate with the nuclear hormone receptor corepressor, N-CoR. N-CoR also interacts with class II deacetylases HDAC4, HDAC5, and HDAC7. In comparison with HDAC1 and HDAC2, HDAC3 remains relatively uncharacterized, and very few proteins have been shown to interact with HDAC3. Using an affinity purification approach, we isolated an enzymatically active HDAC3 complex that contained members of the nuclear receptor corepressor family. Deletion analysis of N-CoR revealed that HDAC3 binds multiple N-CoR regions in vitro and that all of these regions are required for maximal binding in vivo. The N-CoR domains that interact with HDAC3 are distinct from those that bind other HDACs. Transient overexpression of HDAC3 and microinjection of Abs against HDAC3 showed that a component of transcriptional repression mediated by N-CoR depends on HDAC3. Interestingly, data suggest that interaction with a region of N-CoR augments the deacetylase activity of HDAC3. These results provide a possible molecular mechanism for HDAC3 regulation and argue that N-CoR is a platform in which distinct domains can interact with most of the known HDACs.
Xiang-jiao Yang - One of the best experts on this subject based on the ideXlab platform.
-
molecular and functional characterization of histone deacetylase 4 hdac4
Methods of Molecular Biology, 2016Co-Authors: Lin Li, Xiang-jiao YangAbstract:: Histone deacetylases (HDACs) regulate various nuclear and cytoplasmic processes. In mammals, these enzymes are divided into four classes, with class II further divided into two subclasses: IIa (HDAC4, HDAC5, HDAC7, HDAC9) and IIb (HDAC6 and HDAC10). While HDAC6 is mainly cytoplasmic and HDAC10 is pancellular, class IIa HDACs are dynamically shuttled between the nucleus and cytoplasm in a signal-dependent manner, indicating that they are unique signal transducers able to transduce signals from the cytoplasm to chromatin in the nucleus. Once inside the nucleus, class IIa HDACs interact with MEF2 and other transcription factors, mainly acting as transcriptional corepressors. Although class IIa HDACs share many molecular properties in vitro, they play quite distinct roles in vivo. This chapter lists methods that we have used for molecular and biochemical characterization of HDAC4, including development of regular and phospho-specific antibodies, deacetylase activity determination, reporter gene assays, analysis of subcellular localization, and determination of interaction with 14-3-3 and MEF2. Although described specifically for HDAC4, the protocols should be adaptable for analysis to the other three class IIa members, HDAC5, HDAC7, and HDAC9, as well as for other proteins with related properties.
-
histone deacetylase 3 interacts with and deacetylates myocyte enhancer factor 2
Molecular and Cellular Biology, 2007Co-Authors: Serge Grégoire, Edward Seto, Lin Xiao, Xiaohong Zhang, Minghong Xu, Jiarong Li, Jiemin Wong, Xiang-jiao YangAbstract:The myocyte enhancer factor 2 (MEF2) family of transcription factors is not only important for controlling gene expression in normal cellular programs, like muscle differentiation, T-cell apoptosis, neuronal survival, and synaptic differentiation, but has also been linked to cardiac hypertrophy and other pathological conditions. Lysine acetylation has been shown to modulate MEF2 function, but it is not so clear which deacetylase(s) is involved. We report here that treatment of HEK293 cells with trichostatin A or nicotinamide upregulated MEF2D acetylation, suggesting that different deacetylases catalyze the deacetylation. Related to the trichostatin A sensitivity, histone deacetylase 4 (HDAC4) and HDAC5, two known partners of MEF2, exhibited little deacetylase activity towards MEF2D. In contrast, HDAC3 efficiently deacetylated MEF2D in vitro and in vivo. This was specific, since HDAC1, HDAC2, and HDAC8 failed to do so. While HDAC4, HDAC5, HDAC7, and HDAC9 are known to recognize primarily the MEF2-specific domain, we found that HDAC3 interacts directly with the MADS box. In addition, HDAC3 associated with the acetyltransferases p300 and p300/CBP-associated factor (PCAF) to reverse autoacetylation. Furthermore, the nuclear receptor corepressor SMRT (silencing mediator of retinoid acid and thyroid hormone receptor) stimulated the deacetylase activity of HDAC3 towards MEF2 and PCAF. Supporting the physical interaction and deacetylase activity, HDAC3 repressed MEF2-dependent transcription and inhibited myogenesis. These results reveal an unexpected role for HDAC3 and suggest a novel pathway through which MEF2 activity is controlled in vivo.
-
Identification of the ankyrin repeat proteins ANKRA and RFXANK as novel partners of class IIa histone deacetylases.
The Journal of biological chemistry, 2005Co-Authors: Audrey H. Wang, Jenny P.-y. Ting, Eleni Zika, Serge Grégoire, Lin Xiao, Kenneth L. Wright, Xiang-jiao YangAbstract:Abstract Eighteen human histone deacetylases (HDACs) have been identified, and according to their sequence similarity to yeast homologs, these enzymes are grouped into distinct classes. Within class II, HDAC4, HDAC5, HDAC7, and HDAC9 share similar domain organization both within the N-terminal extension and the C-terminal catalytic domain, thus forming a subclass known as class IIa. These HDACs function as signal-responsive transcriptional corepressors. To gain further insight into their function and regulation, we utilized an N-terminal fragment of HDAC4 as bait in yeast two-hybrid screens, which uncovered myocyte enhancer factor 2C, 14-3-3ζ, and ankyrin repeat family A protein (ANKRA). ANKRA is a poorly characterized protein with an ankyrin repeat domain similar to RFXANK, a subunit of the trimeric transcription factor RFX. Mutations on genes of the RFX subunits and the coactivator CIITA are responsible for the bare lymphocyte syndrome, an immunodeficiency disorder attributed to the lack of major histocompatibility complex class II (MHCII) antigens. Through its ankyrin repeat domain, RFXANK interacted with HDAC4. Two RFXANK-binding sites were found on HDAC4 with one located within residues 118–279 and another within residues 448–666. Interestingly, this deacetylase also interacted with CIITA. Consistent with the physical interaction with RFXANK and CIITA, HDAC4 and homologs repressed MHCII expression. These results identify ANKRA, RFXANK, and CIITA as novel targets of class IIa HDACs and suggest that these deacetylases play a role in regulating MHCII expression.
-
identification of hdac10 a novel class ii human histone deacetylase containing a leucine rich domain
Nucleic Acids Research, 2002Co-Authors: Jenny Tong, Jianhong Liu, Nicholas Bertos, Xiang-jiao YangAbstract:Histone acetylation is important for regulating chromatin structure and gene expression. Three classes of mammalian histone deacetylases have been identified. Among class II, there are five known members, namely HDAC4, HDAC5, HDAC6, HDAC7 and HDAC9. Here we describe the identification and characterization of a novel class II member termed HDAC10. It is a 669 residue polypeptide with a bipartite modular structure consisting of an N-terminal Hda1p-related putative deacetylase domain and a C-terminal leucine-rich domain. HDAC10 is widely expressed in adult human tissues and cultured mammalian cells. It is enriched in the cytoplasm and this enrichment is not sensitive to leptomycin B, a specific inhibitor known to block the nuclear export of other class II members. The leucine-rich domain of HDAC10 is responsible for its cytoplasmic enrichment. Recombinant HDAC10 protein possesses histone deacetylase activity, which is sensitive to trichostatin A, a specific inhibitor for known class I and class II histone deacetylases. When tethered to a promoter, HDAC10 is able to repress transcription. Furthermore, HDAC10 interacts with HDAC3 but not with HDAC4 or HDAC6. These results indicate that HDAC10 is a novel class II histone deacetylase possessing a unique leucine-rich domain.
Youngtae Jeong - One of the best experts on this subject based on the ideXlab platform.
-
histone deacetylase isoforms regulate innate immune responses by deacetylating mitogen activated protein kinase phosphatase 1
Journal of Leukocyte Biology, 2014Co-Authors: Youngtae Jeong, Ronghui Du, Charles J. LowensteinAbstract:The MAPK pathway mediates TLR signaling during innate immune responses. We discovered previously that MKP-1 is acetylated, enhancing its interaction with its MAPK substrates and deactivating TLR signaling. As HDACs modulate inflammation by deacetylating histone and nonhistone proteins, we hypothesized that HDACs may regulate LPS-induced inflammation by deacetylating MKP-1. We found that mouse macrophages expressed a subset of HDAC isoforms (HDAC1, HDAC2, and HDAC3), which all interacted with MKP-1. Genetic silencing or pharmacologic inhibition of HDAC1, -2, and -3 increased MKP-1 acetylation in cells. Furthermore, knockdown or pharmacologic inhibition of HDAC1, -2, and -3 decreased LPS-induced phosphorylation of the MAPK member p38. Also, pharmacologic inhibition of HDAC did not decrease MAPK signaling in MKP-1 null cells. Finally, inhibition of HDAC1, -2, and -3 decreased LPS-induced expression of TNF, IL-1 , iNOS (NOS2), and nitrite synthesis. Taken together, our results show that HDAC1, -2, and -3 deacetylate MKP-1 and that this post-translational modification increases MAPK signaling and innate immune signaling. Thus, HDAC1, -2, and -3 isoforms are potential therapeutic targets in inflammatory diseases. J. Leukoc. Biol. 95: 000–000; 2014.
-
histone deacetylase isoforms regulate innate immune responses by deacetylating mitogen activated protein kinase phosphatase 1
Journal of Leukocyte Biology, 2014Co-Authors: Youngtae Jeong, Xiaolei Zhu, Shasha Yin, Jian Wang, Hengmi Cui, Wangsen Cao, Charles J. LowensteinAbstract:The MAPK pathway mediates TLR signaling during innate immune responses. We discovered previously that MKP-1 is acetylated, enhancing its interaction with its MAPK substrates and deactivating TLR signaling. As HDACs modulate inflammation by deacetylating histone and nonhistone proteins, we hypothesized that HDACs may regulate LPS-induced inflammation by deacetylating MKP-1. We found that mouse macrophages expressed a subset of HDAC isoforms (HDAC1, HDAC2, and HDAC3), which all interacted with MKP-1. Genetic silencing or pharmacologic inhibition of HDAC1, -2, and -3 increased MKP-1 acetylation in cells. Furthermore, knockdown or pharmacologic inhibition of HDAC1, -2, and -3 decreased LPS-induced phosphorylation of the MAPK member p38. Also, pharmacologic inhibition of HDAC did not decrease MAPK signaling in MKP-1 null cells. Finally, inhibition of HDAC1, -2, and -3 decreased LPS-induced expression of TNF-α, IL-1β, iNOS (NOS2), and nitrite synthesis. Taken together, our results show that HDAC1, -2, and -3 deacetylate MKP-1 and that this post-translational modification increases MAPK signaling and innate immune signaling. Thus, HDAC1, -2, and -3 isoforms are potential therapeutic targets in inflammatory diseases.
Eric Verdin - One of the best experts on this subject based on the ideXlab platform.
-
histone deacetylase hdac8 associates with smooth muscle alpha actin and is essential for smooth muscle cell contractility
The FASEB Journal, 2005Co-Authors: David Waltregny, Wendy Glenisson, Siv Ly Tran, Brian J North, Eric Verdin, Alain Colige, Vincenzo CastronovoAbstract:Although originally characterized as nuclear enzymes controlling the stability of nucleosomes, histone deacetylases (HDACs) may also exert their activity within the cytosol. Recently, we have demonstrated that HDAC8, a class I HDAC, is a novel, prominently cytosolic marker of smooth muscle differentiation. As HDAC8 displays a striking stress fiber-like pattern of distribution and is coexpressed in vivo with smooth muscle alpha-actin (alpha-SMA) and smooth muscle myosin heavy chain, we have explored the possible participation of this HDAC in smooth muscle cytoskeleton regulation. Cell fractionation assays performed with primary human smooth muscle cells (HSMCs) showed that HDAC8, in contrast to HDAC1 and HDAC3, was enriched in cytoskeleton-bound protein fractions and insoluble cell pellets, suggesting an association of HDAC8 with the cystoskeleton. Coimmunoprecipitation experiments using HSMCs, NIH-3T3 cells, and human prostate tissue lysates further demonstrated that HDAC8 associates with alpha-SMA but not with beta-actin. HDAC8 silencing through RNA interference strongly reduced the capacity of HSMCs to contract collagen lattices. Mock transfections had no effect on HSMC contractily, and transfections with small interfering RNAs (siRNAs) specific for HDAC6, a cytosolic HDAC that functions as an alpha-tubulin deacetylase, resulted in a weak contraction inhibition. Although mock- and HDAC6 siRNA-transfected HSMCs showed no noticeable morphological changes, HDAC8 siRNA-transfected HSMCs displayed a size reduction with diminished cell spreading after replating. Altogether, our findings indicate that HDAC8 associates with the smooth muscle actin cytoskeleton and may regulate the contractile capacity of smooth muscle cells.
-
enzymatic activity associated with class ii hdacs is dependent on a multiprotein complex containing hdac3 and smrt n cor
Molecular Cell, 2002Co-Authors: Wolfgang Fischle, Franck Dequiedt, Michael J Hendzel, Matthew G Guenther, Mitchell A Lazar, Wolfgang Voelter, Eric VerdinAbstract:Histone deacetylases (HDACs) play a key role in regulating eukaryotic gene expression. The HDAC domain, homologous to the yeast repressors RPD3 and HDA1, is considered necessary and sufficient for enzymatic activity. Here, we show that the catalytic domain of HDAC4 interacts with HDAC3 via the transcriptional corepressor N-CoR/SMRT. All experimental conditions leading to the suppression of HDAC4 binding to SMRT/N-CoR and to HDAC3 result in the loss of enzymatic activity associated with HDAC4. In vitro reconstitution experiments indicate that HDAC4 and other class II HDACs are inactive in the context of the SMRT/N-CoR-HDAC3 complex and do not contribute to its enzymatic activity. These observations indicate that class II HDACs regulate transcription by bridging the enzymatically active SMRT/N-CoR-HDAC3 complex and select transcription factors independently of any intrinsic HDAC activity.
-
human HDAC7 histone deacetylase activity is associated with hdac3 in vivo
Journal of Biological Chemistry, 2001Co-Authors: Wolfgang Fischle, Franck Dequiedt, Michael J Hendzel, Wolfgang Voelter, Maryse Fillion, Eric VerdinAbstract:Histone deacetylases (HDACs) are part of transcriptional corepressor complexes and play key roles in regulating chromatin structure. Three different classes of human HDACs have been defined based on their homology to HDACs found in Saccharomyces cerevisiae: RPD3 (class I), HDA1 (class II), and SIR2 (class III). Here we describe the identification and functional characterization of HDAC7, a new member of the human class II HDAC family. Although HDAC7 is localized mostly to the cell nucleus, it is also found in the cytoplasm, suggesting nucleocytoplasmic shuttling. The HDAC activity of HDAC7 maps to a carboxyl-terminal domain and is dependent on the interaction with the class I HDAC, HDAC3, in the cell nucleus. Cytoplasmic HDAC7 that is not bound to HDAC3 is enzymatically inactive. We provide evidence that the transcriptional corepressors SMRT and N-CoR could serve as critical mediators of HDAC7 activity by binding class II HDACs and HDAC3 by two distinct repressor domains. Different class II HDACs reside in the cell nucleus in stable and autonomous complexes with enzymatic activity, but the enzymatic activities associated with HDAC7 and HDAC4 rely on shared cofactors, including HDAC3 and SMRT/N-CoR.
