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Actin-Binding Proteins in Cardiac Hypertrophy. Cells 2022; 11:cells11223566. [PMID: 36428995 PMCID: PMC9688942 DOI: 10.3390/cells11223566] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 11/04/2022] [Accepted: 11/08/2022] [Indexed: 11/16/2022] Open
Abstract
The heart reacts to a large number of pathological stimuli through cardiac hypertrophy, which finally can lead to heart failure. However, the molecular mechanisms of cardiac hypertrophy remain elusive. Actin participates in the formation of highly differentiated myofibrils under the regulation of actin-binding proteins (ABPs), which provides a structural basis for the contractile function and morphological change in cardiomyocytes. Previous studies have shown that the functional abnormality of ABPs can contribute to cardiac hypertrophy. Here, we review the function of various actin-binding proteins associated with the development of cardiac hypertrophy, which provides more references for the prevention and treatment of cardiomyopathy.
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2
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Lew ZX, Zhou HM, Fang YY, Ye Z, Zhong W, Yang XY, Yu Z, Chen DY, Luo SM, Chen LF, Lin Y. Transgelin interacts with PARP1 in human colon cancer cells. Cancer Cell Int 2020; 20:366. [PMID: 32774160 PMCID: PMC7398379 DOI: 10.1186/s12935-020-01461-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2020] [Accepted: 07/27/2020] [Indexed: 01/13/2023] Open
Abstract
Background Transgelin, an actin-binding protein, is associated with cytoskeleton remodeling. Findings from our previous studies demonstrated that transgelin was up-regulated in node-positive colorectal cancer (CRC) versus node-negative disease. Over-expression of TAGLN affected the expression of 256 downstream transcripts and increased the metastatic potential of colon cancer cells in vitro and in vivo. This study aims to explore the mechanisms through which transgelin participates in the metastasis of colon cancer cells. Methods Immunofluorescence and immunoblotting analysis were used to determine the cellular localization of endogenous and exogenous transgelin in colon cancer cells. Co-immunoprecipitation and subsequently high-performance liquid chromatography/tandem mass spectrometry were performed to identify the proteins that were potentially interacting with transgelin. The 256 downstream transcripts regulated by transgelin were analyzed with bioinformatics methods to discriminate the specific key genes and signaling pathways. The Gene-Cloud of Biotechnology Information (GCBI) tools were used to predict the potential transcription factors (TFs) for the key genes. The predicted TFs corresponded to the proteins identified to interact with transgelin. The interaction between transgelin and the TFs was verified by co-immunoprecipitation and immunofluorescence. Results Transgelin was found to localize in both the cytoplasm and nucleus of the colon cancer cells. Approximately 297 proteins were identified to interact with transgelin. The overexpression of TAGLN led to the differential expression of 184 downstream genes. Network topology analysis discriminated seven key genes, including CALM1, MYO1F, NCKIPSD, PLK4, RAC1, WAS and WIPF1, which are mostly involved in the Rho signaling pathway. Poly (ADP-ribose) polymerase-1 (PARP1) was predicted as the unique TF for the key genes and concurrently corresponded to the DNA-binding proteins potentially interacting with transgelin. The interaction between PARP1 and transgelin in human RKO colon cancer cells was further validated by immunoprecipitation and immunofluorescence assays. Conclusions Our results suggest that transgelin binds to PARP1 and regulates the expression of downstream key genes, which are mainly involved in the Rho signaling pathway, and thus participates in the metastasis of colon cancer.
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Affiliation(s)
- Zhen-Xian Lew
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China.,Department of Gastroenterology and Hepatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China.,Department of Surgery, Guangzhou Concord Cancer Center, Guangzhou, 510045 China
| | - Hui-Min Zhou
- Department of Gastroenterology and Hepatology, The First Affiliated Hospital, School of Clinical Medicine of Guangdong Pharmaceutical University, Guangzhou, 510080 China
| | - Yuan-Yuan Fang
- Intensive Care Unit, Tongling People's Hospital, Tongling City, 244000 Anhui province China
| | - Zhen Ye
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China.,Department of Gastroenterology and Hepatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China
| | - Wa Zhong
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China.,Department of Gastroenterology and Hepatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China
| | - Xin-Yi Yang
- Digestive Medicine Center, The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen, 518107 China
| | - Zhong Yu
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China.,Department of Gastroenterology and Hepatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China
| | - Dan-Yu Chen
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China.,Department of Gastroenterology and Hepatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China
| | - Si-Min Luo
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China.,Department of Gastroenterology and Hepatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China
| | - Li-Fei Chen
- Department of Nephrology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, Guangzhou, 510120 China
| | - Ying Lin
- Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China.,Department of Gastroenterology and Hepatology, Sun Yat-sen Memorial Hospital, Sun Yat-sen University, No. 107 West Yanjiang Road, Guangzhou, 510120 Guangdong China
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Liu Y, Zheng B, Zhang XH, Nie CJ, Li YH, Wen JK. Localization and function of KLF4 in cytoplasm of vascular smooth muscle cell. Biochem Biophys Res Commun 2013; 436:162-8. [PMID: 23726909 DOI: 10.1016/j.bbrc.2013.05.067] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2013] [Accepted: 05/16/2013] [Indexed: 01/04/2023]
Abstract
The Krüppel-like factor 4 is a DNA-binding transcriptional regulator that regulates a diverse array of cellular processes, including development, differentiation, proliferation, and apoptosis. The previous studies about KLF4 functions mainly focused on its role as a transcription factor, its functions in the cytoplasm are still unknown. In this study, we found that PDGF-BB could prompt the translocation of KLF4 to the cytoplasm through CRM1-mediated nuclear export pathway in vascular smooth muscle cells (VSMCs) and increased the interaction of KLF4 with actin in the cytoplasm. Further study showed that both KLF4 phosphorylation and SUMOylation induced by PDGF-BB participates in regulation of cytoskeletal organization by stabilizing the actin cytoskeleton in VSMCs. In conclusion, these results identify that KLF4 participates in the cytoskeletal organization by stabilizing cytoskeleton in the cytoplasm of VSMCs.
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MESH Headings
- Actin Cytoskeleton/drug effects
- Actin Cytoskeleton/metabolism
- Actins/metabolism
- Active Transport, Cell Nucleus/drug effects
- Animals
- Becaplermin
- Blotting, Western
- Cell Nucleus/metabolism
- Cells, Cultured
- Cytoplasm/drug effects
- Cytoplasm/metabolism
- HEK293 Cells
- Humans
- Karyopherins/metabolism
- Kruppel-Like Factor 4
- Kruppel-Like Transcription Factors/genetics
- Kruppel-Like Transcription Factors/metabolism
- Male
- Microscopy, Confocal
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/metabolism
- Phosphorylation/drug effects
- Protein Binding/drug effects
- Proto-Oncogene Proteins c-sis/pharmacology
- Rats
- Rats, Sprague-Dawley
- Receptors, Cytoplasmic and Nuclear/metabolism
- Sumoylation/drug effects
- Exportin 1 Protein
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Affiliation(s)
- Yan Liu
- Department of Biochemistry and Molecular Biology, The Key Laboratory of Neurobiology and Vascular Biology, China
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4
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Shi HJ, Wen JK, Miao SB, Liu Y, Zheng B. KLF5 and hhLIM cooperatively promote proliferation of vascular smooth muscle cells. Mol Cell Biochem 2012; 367:185-94. [DOI: 10.1007/s11010-012-1332-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2012] [Accepted: 05/03/2012] [Indexed: 12/11/2022]
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Li A, Ponten F, dos Remedios CG. The interactome of LIM domain proteins: The contributions of LIM domain proteins to heart failure and heart development. Proteomics 2012; 12:203-25. [DOI: 10.1002/pmic.201100492] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Revised: 11/07/2011] [Accepted: 11/08/2011] [Indexed: 12/22/2022]
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6
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Zheng B, Han M, Shu YN, Li YJ, Miao SB, Zhang XH, Shi HJ, Zhang T, Wen JK. HDAC2 phosphorylation-dependent Klf5 deacetylation and RARα acetylation induced by RAR agonist switch the transcription regulatory programs of p21 in VSMCs. Cell Res 2011; 21:1487-508. [PMID: 21383775 PMCID: PMC3193446 DOI: 10.1038/cr.2011.34] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 12/19/2010] [Accepted: 01/10/2011] [Indexed: 02/03/2023] Open
Abstract
Abnormal proliferation of vascular smooth muscle cells (VSMCs) occurs in hypertension, atherosclerosis and restenosis after angioplasty, leading to pathophysiological vascular remodeling. As an important growth arrest gene, p21 plays critical roles in vascular remodeling. Regulation of p21 expression by retinoic acid receptor (RAR) and its ligand has important implications for control of pathological vascular remodeling. Nevertheless, the mechanism of RAR-mediated p21 expression in VSMCs remains poorly understood. Here, we show that, under basal conditions, RARα forms a complex with histone deacetylase 2 (HDAC2) and Krüppel-like factor 5 (Klf5) at the p21 promoter to inhibit its expression. Upon RARα agonist stimulation, HDAC2 is phosphorylated by CK2α. Phosphorylation of HDAC2, on the one hand, promotes its dissociation from RARα, thus allowing the liganded-RARα to interact with co-activators; on the other hand, it increases its interaction with Klf5, thus leading to deacetylation of Klf5. Deacetylation of Klf5 facilitates its dissociation from the p21 promoter, relieving its repressive effect on the p21 promoter. Interference with HDAC2 phosphorylation by either CK2α knockdown or the use of phosphorylation-deficient mutant of HDAC2 prevents the dissociation of Klf5 from the p21 promoter and impairs RAR agonist-induced p21 activation. Our results reveal a novel mechanism involving a phosphorylation-deacetylation cascade that functions to remove the basal repression complex from the p21 promoter upon RAR agonist treatment, allowing for optimum agonist-induced p21 expression.
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MESH Headings
- Acetylation
- Animals
- Casein Kinase II/genetics
- Casein Kinase II/metabolism
- Cell Line
- Cyclin-Dependent Kinase Inhibitor p21/genetics
- Cyclin-Dependent Kinase Inhibitor p21/metabolism
- Gene Expression Regulation/physiology
- Histone Deacetylase 2/genetics
- Histone Deacetylase 2/metabolism
- Kruppel-Like Transcription Factors/genetics
- Kruppel-Like Transcription Factors/metabolism
- Male
- Multiprotein Complexes/genetics
- Multiprotein Complexes/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Mutation
- Myocytes, Smooth Muscle/cytology
- Myocytes, Smooth Muscle/metabolism
- Phosphorylation/physiology
- Promoter Regions, Genetic/physiology
- Rats
- Rats, Sprague-Dawley
- Receptors, Retinoic Acid/agonists
- Receptors, Retinoic Acid/genetics
- Receptors, Retinoic Acid/metabolism
- Repressor Proteins/genetics
- Repressor Proteins/metabolism
- Retinoic Acid Receptor alpha
- Transcription, Genetic/physiology
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Affiliation(s)
- Bin Zheng
- Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| | - Mei Han
- Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| | - Ya-nan Shu
- Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| | - Ying-jie Li
- Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| | - Sui-bing Miao
- Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| | - Xin-hua Zhang
- Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| | - Hui-jing Shi
- Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| | - Tian Zhang
- Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang 050017, China
| | - Jin-kun Wen
- Department of Biochemistry and Molecular Biology, Key Laboratory of Neural and Vascular Biology, Ministry of Education, Hebei Medical University, No. 361, Zhongshan East Road, Shijiazhuang 050017, China
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Krüppel-like factor 4 interacts with p300 to activate mitofusin 2 gene expression induced by all-trans retinoic acid in VSMCs. Acta Pharmacol Sin 2010; 31:1293-302. [PMID: 20711222 DOI: 10.1038/aps.2010.96] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
AIM To elucidate how krüppel-like factor 4 (KLF4) activates mitofusin 2 (mfn-2) expression in all-trans retinoic acid (ATRA)-induced vascular smooth muscle cell (VSMC) differentiation. METHODS The mfn-2 promoter-reporter constructs and the KLF4 acetylation-deficient or phosphorylation-deficient mutants were constructed. Adenoviral vector of KLF4-mediated overexpression and Western blot analysis were used to determine the effect of KLF4 on mfn-2 expression. The luciferase assay and chromatin immunoprecipitation were used to detect the transactivation of KLF4 on mfn-2 gene expression. Co-immunoprecipitation and GST pull-down assays were used to determine the modification of KLF4 and interaction of KLF4 with p300 in VSMCs. RESULTS KLF4 mediated ATRA-induced mfn-2 expression in VSMCs. KLF4 bound directly to the mfn-2 promoter and activated its transcription. ATRA increased the interaction of KLF4 with p300 by inducing KLF4 phosphorylation via activation of JNK and p38 MAPK signaling. KLF4 acetylation by p300 increased its activity to transactivate the mfn-2 promoter. CONCLUSION ATRA induces KLF4 acetylation by p300 and increases the ability of KLF4 to transactivate the mfn-2 promoter in VSMCs.
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Zheng B, Han M, Bernier M, Zhang XH, Meng F, Miao SB, He M, Zhao XM, Wen JK. Krüppel-like factor 4 inhibits proliferation by platelet-derived growth factor receptor beta-mediated, not by retinoic acid receptor alpha-mediated, phosphatidylinositol 3-kinase and ERK signaling in vascular smooth muscle cells. J Biol Chem 2009; 284:22773-85. [PMID: 19531492 DOI: 10.1074/jbc.m109.026989] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Proliferation inhibition of vascular smooth muscle cells (VSMCs) is governed by the activity of a transcription factor network. Krüppel-like factor 4 (Klf4), retinoic acid receptor (RAR alpha), and platelet-derived growth factor receptor (PDGFR) are expressed in VSMCs and are components of such a network. However, the relationship among them in the regulation of VSMC proliferation remains unknown. Here, we investigated the mechanisms whereby Klf4 mediates the growth inhibitory effects in VSMCs through RAR alpha and PDGFR beta. We demonstrated that Klf4 directly binds to the 5' regulatory region of RAR alpha, down-regulates RAR alpha expression, and specifically inhibits RAR alpha-mediated phosphatidylinositol 3-kinase (PI3K) and ERK signaling in cultured VSMCs induced by the synthetic retinoid Am80. Of particular interest, Klf4 inhibits RAR alpha and PDGFR beta expression while blocking PI3K and ERK signaling induced by Am80 and PDGF-BB, respectively. The anti-proliferative effects of Klf4 on neointimal formation depend largely on PDGFR-mediated PI3K signaling without involvement of the RAR alpha-activated signaling pathways. These findings provide a novel mechanism for signal suppression and growth inhibitory effects of Klf4 in VSMCs. Moreover, the results of this study suggest that Klf4 is one of the key mediators of retinoid actions in VSMCs.
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Affiliation(s)
- Bin Zheng
- Department of Biochemistry and Molecular Biology, Hebei Medical University, Zhongshan East Road, Shijiazhuang 050017, China
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9
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Meng F, Han M, Zheng B, Wang C, Zhang R, Zhang XH, Wen JK. All-trans retinoic acid increases KLF4 acetylation by inducing HDAC2 phosphorylation and its dissociation from KLF4 in vascular smooth muscle cells. Biochem Biophys Res Commun 2009; 387:13-8. [PMID: 19486889 DOI: 10.1016/j.bbrc.2009.05.112] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 05/25/2009] [Indexed: 10/20/2022]
Abstract
The zinc finger transcription factor Krüppel-like factor 4 (KLF4) has been implicated in vascular smooth muscle cell differentiation induced by all-trans retinoic acid (ATRA). However, the molecular mechanism whereby ATRA regulates KLF4 activity is still poorly understood. Here, we show that ATRA-induced histone deacetylase 2 (HDAC2) phosphorylation at Ser424 in VSMCs and inhibited the interaction of HDAC2 with KLF4. Inhibiting JNK by JNK inhibitor SP600125 or knockdown of JNK by JNK siRNA abrogated ATRA-induced HDAC2 phosphorylation and reversed ATRA-induced suppression of the interaction of HDAC2 with KLF4. We further demonstrated that HDAC2 directly deacetylated KLF4, and that KLF4 acetylation and binding activity of KLF4 to the SM22alpha promoter were significantly increased in ATRA-treated VSMCs. Collectively, our results indicate that ATRA induces HDAC2 phosphorylation mediated by JNK signaling, and thus causes HDAC2 dissociation from KLF4, subsequently leading to the increase in KLF4 acetylation.
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Affiliation(s)
- Fang Meng
- Department of Biochemistry and Molecular Biology, Hebei Medical University, Shijiazhuang, PR China
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10
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Zheng B, Han M, Bernier M, Wen JK. Nuclear actin and actin-binding proteins in the regulation of transcription and gene expression. FEBS J 2009; 276:2669-85. [PMID: 19459931 PMCID: PMC2978034 DOI: 10.1111/j.1742-4658.2009.06986.x] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Nuclear actin is involved in the transcription of all three RNA polymerases, in chromatin remodeling and in the formation of heterogeneous nuclear ribonucleoprotein complexes, as well as in recruitment of the histone modifier to the active gene. In addition, actin-binding proteins (ABPs) control actin nucleation, bundling, filament capping, fragmentation and monomer availability in the cytoplasm. In recent years, more and more attention has focused on the role of actin and ABPs in the modulation of the subcellular localization of transcriptional regulators. This review focuses on recent developments in the study of transcription and transcriptional regulation by nuclear actin, and the regulation of muscle-specific gene expression, nuclear receptor and transcription complexes by ABPs. Among the ABPs, striated muscle activator of Rho signaling and actin-binding LIM protein regulate actin dynamics and serum response factor-dependent muscle-specific gene expression. Functionally and structurally unrelated cytoplasmic ABPs interact cooperatively with nuclear receptor and regulate its transactivation. Furthermore, ABPs also participate in the formation of transcription complexes.
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Affiliation(s)
- Bin Zheng
- Department of Biochemistry and Molecular Biology, Hebei Medical University, Shijiazhuang, China
| | - Mei Han
- Department of Biochemistry and Molecular Biology, Hebei Medical University, Shijiazhuang, China
| | - Michel Bernier
- Laboratory of Clinical Investigation, National Institute on Aging, National Institutes of Health, Baltimore, Maryland, USA
| | - Jin-kun Wen
- Department of Biochemistry and Molecular Biology, Hebei Medical University, Shijiazhuang, China
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Zheng B, Wen JK, Han M. hhLIM is a novel F-actin binding protein involved in actin cytoskeleton remodeling. FEBS J 2008; 275:1568-1578. [PMID: 18331358 DOI: 10.1111/j.1742-4658.2008.06315.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Human heart LIM protein (hhLIM) is a newly cloned protein. In vitro analyses showed that green fluorescent protein (GFP)-tagged hhLIM protein accumulated in the cytoplasm of C2C12 cells and colocalized with F-actin, indicating that hhLIM is an actin-binding protein in C2C12 cells. Overexpression of hhLIM-GFP in C2C12 cells significantly stabilized actin filaments and delayed depolymerization of the actin cytoskeleton induced by cytochalasin B treatment. Expression of hhLIM-GFP in C2C12 cells also induced significant changes in the organization of the actin cytoskeleton, specifically, fewer and thicker actin bundles than in control cells, suggesting that hhLIM functions as an actin-bundling protein. This hypothesis was confirmed using low-speed co-sedimentation assays and direct observation of F-actin bundles that formed in vitro in the presence of hhLIM. hhLIM has two LIM domains. To identify the essential regions and sites for association, a series of truncated mutants was constructed which showed that LIM domain 2 has the same activity as full-length hhLIM. To further characterize the binding sites, the LIM domain was functionally destructed by replacing cysteine with serine in domain 2, and results showed that the second LIM domain plays a central role in bundling of F-actin. Taken together, these data identify hhLIM as an actin-binding protein that increases actin cytoskeleton stability by promoting bundling of actin filaments.
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Affiliation(s)
- Bin Zheng
- Department of Biochemistry and Molecular Biology, Hebei Medical University, Shijiazhuang, China
| | - Jin-Kun Wen
- Department of Biochemistry and Molecular Biology, Hebei Medical University, Shijiazhuang, China
| | - Mei Han
- Department of Biochemistry and Molecular Biology, Hebei Medical University, Shijiazhuang, China
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