1
|
Zhu H, Narita M, Joseph JA, Krainer G, Arter WE, Olan I, Saar KL, Ermann N, Espinosa JR, Shen Y, Kuri MA, Qi R, Welsh TJ, Collepardo‐Guevara R, Narita M, Knowles TPJ. The Chromatin Regulator HMGA1a Undergoes Phase Separation in the Nucleus. Chembiochem 2023; 24:e202200450. [PMID: 36336658 PMCID: PMC10098602 DOI: 10.1002/cbic.202200450] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Revised: 10/20/2022] [Indexed: 11/09/2022]
Abstract
The protein high mobility group A1 (HMGA1) is an important regulator of chromatin organization and function. However, the mechanisms by which it exerts its biological function are not fully understood. Here, we report that the HMGA isoform, HMGA1a, nucleates into foci that display liquid-like properties in the nucleus, and that the protein readily undergoes phase separation to form liquid condensates in vitro. By bringing together machine-leaning modelling, cellular and biophysical experiments and multiscale simulations, we demonstrate that phase separation of HMGA1a is promoted by protein-DNA interactions, and has the potential to be modulated by post-transcriptional effects such as phosphorylation. We further show that the intrinsically disordered C-terminal tail of HMGA1a significantly contributes to its phase separation through electrostatic interactions via AT hooks 2 and 3. Our work sheds light on HMGA1 phase separation as an emergent biophysical factor in regulating chromatin structure.
Collapse
Affiliation(s)
- Hongjia Zhu
- Centre for Misfolding DiseasesYusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
| | - Masako Narita
- Cancer Research UK Cambridge InstituteLi Ka Shing CentreUniversity of CambridgeCambridgeUK
| | - Jerelle A. Joseph
- Department of GeneticsUniversity of CambridgeCambridgeUK
- Cavendish LaboratoryDepartment of PhysicsUniversity of CambridgeJJ Thomson AvenueCambridgeUK
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
| | - Georg Krainer
- Centre for Misfolding DiseasesYusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
| | - William E. Arter
- Centre for Misfolding DiseasesYusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
- Transition Bio Ltd., Maxwell CentreJJ Thomson AvenueCambridgeUK
| | - Ioana Olan
- Cancer Research UK Cambridge InstituteLi Ka Shing CentreUniversity of CambridgeCambridgeUK
| | - Kadi L. Saar
- Centre for Misfolding DiseasesYusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
- Transition Bio Ltd., Maxwell CentreJJ Thomson AvenueCambridgeUK
| | - Niklas Ermann
- Transition Bio Ltd., Maxwell CentreJJ Thomson AvenueCambridgeUK
| | - Jorge R. Espinosa
- Cavendish LaboratoryDepartment of PhysicsUniversity of CambridgeJJ Thomson AvenueCambridgeUK
| | - Yi Shen
- School of Chemical and Biomolecular EngineeringThe University of SydneySydneyAustralia
| | - Masami Ando Kuri
- Cancer Research UK Cambridge InstituteLi Ka Shing CentreUniversity of CambridgeCambridgeUK
| | - Runzhang Qi
- Centre for Misfolding DiseasesYusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
| | - Timothy J. Welsh
- Centre for Misfolding DiseasesYusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
| | - Rosana Collepardo‐Guevara
- Department of GeneticsUniversity of CambridgeCambridgeUK
- Cavendish LaboratoryDepartment of PhysicsUniversity of CambridgeJJ Thomson AvenueCambridgeUK
- Yusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
| | - Masashi Narita
- Cancer Research UK Cambridge InstituteLi Ka Shing CentreUniversity of CambridgeCambridgeUK
| | - Tuomas P. J. Knowles
- Centre for Misfolding DiseasesYusuf Hamied Department of ChemistryUniversity of CambridgeCambridgeUK
- Cavendish LaboratoryDepartment of PhysicsUniversity of CambridgeJJ Thomson AvenueCambridgeUK
| |
Collapse
|
2
|
Wang L, Zhang J, Xia M, Liu C, Zu X, Zhong J. High Mobility Group A1 (HMGA1): Structure, Biological Function, and Therapeutic Potential. Int J Biol Sci 2022; 18:4414-4431. [PMID: 35864955 PMCID: PMC9295051 DOI: 10.7150/ijbs.72952] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 06/24/2022] [Indexed: 11/26/2022] Open
Abstract
High mobility group A1 (HMGA1) is a nonhistone chromatin structural protein characterized by no transcriptional activity. It mainly plays a regulatory role by modifying the structure of DNA. A large number of studies have confirmed that HMGA1 regulates genes related to tumours in the reproductive system, digestive system, urinary system and haematopoietic system. HMGA1 is rare in adult cells and increases in highly proliferative cells such as embryos. After being stimulated by external factors, it will produce effects through the Wnt/β-catenin, PI3K/Akt, Hippo and MEK/ERK pathways. In addition, HMGA1 also affects the ageing, apoptosis, autophagy and chemotherapy resistance of cancer cells, which are linked to tumorigenesis. In this review, we summarize the mechanisms of HMGA1 in cancer progression and discuss the potential clinical application of targeted HMGA1 therapy, indicating that targeted HMGA1 is of great significance in the diagnosis and treatment of malignancy.
Collapse
Affiliation(s)
- Lu Wang
- Institute of Clinical Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, PR China
| | - Ji Zhang
- Department of Clinical Laboratory, Shenzhen Traditional Chinese Medicine Hospital, Shenzhen 518033, Guangdong, China
| | - Min Xia
- Institute of Clinical Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, PR China.,Cancer Research Institute, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, PR China
| | - Chang Liu
- Department of Endocrinology and Metabolism, The First People's Hospital of Chenzhou, First School of Clinical Medicine, University of Southern Medical, Guangzhou 510515, Guangdong, China
| | - Xuyu Zu
- Institute of Clinical Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, PR China.,Cancer Research Institute, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, PR China
| | - Jing Zhong
- Institute of Clinical Medicine, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, PR China.,Cancer Research Institute, The First Affiliated Hospital, Hengyang Medical School, University of South China, Hengyang, Hunan, 421001, PR China
| |
Collapse
|
3
|
Kohl B, Zhong X, Herrmann C, Stoll R. Phosphorylation orchestrates the structural ensemble of the intrinsically disordered protein HMGA1a and modulates its DNA binding to the NFκB promoter. Nucleic Acids Res 2020; 47:11906-11920. [PMID: 31340016 PMCID: PMC7145567 DOI: 10.1093/nar/gkz614] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/14/2019] [Accepted: 07/05/2019] [Indexed: 12/27/2022] Open
Abstract
High Mobility Group Protein A1a (HMGA1a) is a highly abundant nuclear protein, which plays a crucial role during embryogenesis, cell differentiation, and neoplasia. Here, we present the first ever NMR-based structural ensemble of full length HMGA1a. Our results show that the protein is not completely random coil but adopts a compact structure consisting of transient long-range contacts, which is regulated by post-translational phosphorylation. The CK2-, cdc2- and cdc2/CK2-phosphorylated forms of HMGA1a each exhibit a different binding affinity towards the PRD2 element of the NFκB promoter. Our study identifies connected regions between phosphorylation sites in the wildtype ensemble that change considerably upon phosphorylation, indicating that these posttranslational modifications sites are part of an electrostatic contact network that alters the structural ensemble by shifting the conformational equilibrium. Moreover, ITC data reveal that the CK2-phosphorylated HMGA1a exhibits a different DNA promoter binding affinity for the PRD2 element. Furthermore, we present the first structural model for AT-hook 1 of HMGA1a that can adopt a transient α-helical structure, which might serve as an additional regulatory mechanism in HMAG1a. Our findings will help to develop new therapeutic strategies against HMGA1a-associated cancers by taking posttranslational modifications into consideration.
Collapse
Affiliation(s)
- Bastian Kohl
- Faculty of Chemistry and Biochemistry, Biomolecular NMR Spectroscopy, Ruhr University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Xueyin Zhong
- Faculty of Chemistry and Biochemistry, Biomolecular NMR Spectroscopy, Ruhr University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Christian Herrmann
- Faculty of Chemistry and Biochemistry, Protein Interactions, Ruhr University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| | - Raphael Stoll
- Faculty of Chemistry and Biochemistry, Biomolecular NMR Spectroscopy, Ruhr University of Bochum, Universitätsstraße 150, 44780 Bochum, Germany
| |
Collapse
|
4
|
The Mammalian High Mobility Group Protein AT-Hook 2 (HMGA2): Biochemical and Biophysical Properties, and Its Association with Adipogenesis. Int J Mol Sci 2020; 21:ijms21103710. [PMID: 32466162 PMCID: PMC7279267 DOI: 10.3390/ijms21103710] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 04/30/2020] [Accepted: 05/12/2020] [Indexed: 12/11/2022] Open
Abstract
The mammalian high-mobility-group protein AT-hook 2 (HMGA2) is a small DNA-binding protein and consists of three “AT-hook” DNA-binding motifs and a negatively charged C-terminal motif. It is a multifunctional nuclear protein directly linked to obesity, human height, stem cell youth, human intelligence, and tumorigenesis. Biochemical and biophysical studies showed that HMGA2 is an intrinsically disordered protein (IDP) and could form homodimers in aqueous buffer solution. The “AT-hook” DNA-binding motifs specifically bind to the minor groove of AT-rich DNA sequences and induce DNA-bending. HMGA2 plays an important role in adipogenesis most likely through stimulating the proliferative expansion of preadipocytes and also through regulating the expression of transcriptional factor Peroxisome proliferator-activated receptor γ (PPARγ) at the clonal expansion step from preadipocytes to adipocytes. Current evidence suggests that a main function of HMGA2 is to maintain stemness and renewal capacity of stem cells by which HMGA2 binds to chromosome and lock chromosome into a specific state, to allow the human embryonic stem cells to maintain their stem cell potency. Due to the importance of HMGA2 in adipogenesis and tumorigenesis, HMGA2 is considered a potential therapeutic target for anticancer and anti-obesity drugs. Efforts are taken to identify inhibitors targeting HMGA2.
Collapse
|
5
|
Sumter TF, Xian L, Huso T, Koo M, Chang YT, Almasri TN, Chia L, Inglis C, Reid D, Resar LMS. The High Mobility Group A1 (HMGA1) Transcriptome in Cancer and Development. Curr Mol Med 2016; 16:353-93. [PMID: 26980699 DOI: 10.2174/1566524016666160316152147] [Citation(s) in RCA: 83] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 02/15/2016] [Accepted: 03/10/2016] [Indexed: 01/19/2023]
Abstract
BACKGROUND & OBJECTIVES Chromatin structure is the single most important feature that distinguishes a cancer cell from a normal cell histologically. Chromatin remodeling proteins regulate chromatin structure and high mobility group A (HMGA1) proteins are among the most abundant, nonhistone chromatin remodeling proteins found in cancer cells. These proteins include HMGA1a/HMGA1b isoforms, which result from alternatively spliced mRNA. The HMGA1 gene is overexpressed in cancer and high levels portend a poor prognosis in diverse tumors. HMGA1 is also highly expressed during embryogenesis and postnatally in adult stem cells. Overexpression of HMGA1 drives neoplastic transformation in cultured cells, while inhibiting HMGA1 blocks oncogenic and cancer stem cell properties. Hmga1 transgenic mice succumb to aggressive tumors, demonstrating that dysregulated expression of HMGA1 causes cancer in vivo. HMGA1 is also required for reprogramming somatic cells into induced pluripotent stem cells. HMGA1 proteins function as ancillary transcription factors that bend chromatin and recruit other transcription factors to DNA. They induce oncogenic transformation by activating or repressing specific genes involved in this process and an HMGA1 "transcriptome" is emerging. Although prior studies reveal potent oncogenic properties of HMGA1, we are only beginning to understand the molecular mechanisms through which HMGA1 functions. In this review, we summarize the list of putative downstream transcriptional targets regulated by HMGA1. We also briefly discuss studies linking HMGA1 to Alzheimer's disease and type-2 diabetes. CONCLUSION Further elucidation of HMGA1 function should lead to novel therapeutic strategies for cancer and possibly for other diseases associated with aberrant HMGA1 expression.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | - L M S Resar
- Department of Medicine, Faculty of the Johns Hopkins University School of Medicine, 720 Rutland Avenue, Ross Research Building, Room 1025, Baltimore, MD 21205-2109, USA.
| |
Collapse
|
6
|
HMGA1 is a novel downstream nuclear target of the insulin receptor signaling pathway. Sci Rep 2012; 2:251. [PMID: 22355763 PMCID: PMC3273854 DOI: 10.1038/srep00251] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2011] [Accepted: 01/18/2012] [Indexed: 02/07/2023] Open
Abstract
High-mobility group AT-hook 1 (HMGA1) protein is an important nuclear factor that activates gene transcription by binding to AT-rich sequences in the promoter region of DNA. We previously demonstrated that HMGA1 is a key regulator of the insulin receptor (INSR) gene and individuals with defects in HMGA1 have decreased INSR expression and increased susceptibility to type 2 diabetes mellitus. In addition, there is evidence that intracellular regulatory molecules that are employed by the INSR signaling system are involved in post-translational modifications of HMGA1, including protein phosphorylation. It is known that phosphorylation of HMGA1 reduces DNA-binding affinity and transcriptional activation. In the present study, we investigated whether activation of the INSR by insulin affected HMGA1 protein phosphorylation and its regulation of gene transcription. Collectively, our findings indicate that HMGA1 is a novel downstream target of the INSR signaling pathway, thus representing a new critical nuclear mediator of insulin action and function.
Collapse
|
7
|
Sharma A, Ray R, Rajeswari MR. High-Mobility Group A1 (HMGA1) Protein Expression Correlates With Cisplatin-Induced Cell Death in Squamous Cell Carcinoma of Skin. Cancer Invest 2010. [DOI: 10.1080/07357900903286933] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
8
|
Sgarra R, Maurizio E, Zammitti S, Lo Sardo A, Giancotti V, Manfioletti G. Macroscopic Differences in HMGA Oncoproteins Post-Translational Modifications: C-Terminal Phosphorylation of HMGA2 Affects Its DNA Binding Properties. J Proteome Res 2009; 8:2978-89. [DOI: 10.1021/pr900087r] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Riccardo Sgarra
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Elisa Maurizio
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | - Salvina Zammitti
- Department of Life Sciences, University of Trieste, Trieste, Italy
| | | | | | | |
Collapse
|
9
|
Wiśniewski JR, Zougman A, Krüger S, Ziółkowski P, Pudełko M, Bębenek M, Mann M. Constitutive and dynamic phosphorylation and acetylation sites on NUCKS, a hypermodified nuclear protein, studied by quantitative proteomics. Proteins 2008; 73:710-8. [DOI: 10.1002/prot.22104] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
|
10
|
Zhang Q, Wang Y. Homeodomain-interacting protein kinase-2 (HIPK2) phosphorylates HMGA1a at Ser-35, Thr-52, and Thr-77 and modulates its DNA binding affinity. J Proteome Res 2007; 6:4711-9. [PMID: 17960875 DOI: 10.1021/pr700571d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The chromosomal high-mobility group A (HMGA) proteins, composed of HMGA1a, HMGA1b and HMGA2, play important roles in the regulation of numerous processes in eukaryotic cells, such as transcriptional regulation, DNA repair, RNA processing, and chromatin remodeling. The biological activities of HMGA1 proteins are highly regulated by their post-translational modifications (PTMs), including acetylation, methylation, and phosphorylation. Recently, it was found that the homeodomain-interacting protein kinase-2 (HIPK2), a newly identified serine/threonine kinase, co-immunoprecipitated with, and phosphorylated, HMGA1 proteins. However, the sites and the biological significance of the phosphorylation have not been elucidated. Here, we found that HIPK2 phosphorylates HMGA1a at Ser-35, Thr-52, and Thr-77, and HMGA1b at Thr-41 and Thr-66. In addition, we demonstrated that cdc2, which is known to phosphorylate HMGA1 proteins, could induce the phosphorylation of HMGA1 proteins at the same Ser/Thr sites. The two kinases, however, exhibited different site preferences for the phosphorylation: The preference for HIPK2 phosphorylation followed the order of Thr-77 > Thr-52 > Ser-35, whereas the order for cdc2 phosphorylation was Thr-52 > Thr-77 > Ser-35. Moreover, we found that the HIPK2-phosphorylated HMGA1a reduced the binding affinity of HMGA1a to human germ line promoter, and the drop in binding affinity induced by HIPK2 phosphorylation was lower than that introduced by cdc2 phosphorylation, which is consistent with the notion that the second AT-hook in HMGA1a is more important for DNA binding than the third AT-hook.
Collapse
|
11
|
Zhang Q, Zhang K, Zou Y, Perna A, Wang Y. A quantitative study on the in vitro and in vivo acetylation of high mobility group A1 proteins. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2007; 18:1569-78. [PMID: 17627840 PMCID: PMC2020522 DOI: 10.1016/j.jasms.2007.05.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2007] [Revised: 05/27/2007] [Accepted: 05/30/2007] [Indexed: 05/16/2023]
Abstract
High mobility group (HMG) A1 proteins are subject to a number of post-translational modifications, which may regulate their function in gene transcription and other cellular processes. We examined, by using mass spectrometry, the acetylation of HMGA1a and HMGA1b proteins induced by histone acetyltransferases p300 and PCAF in vitro and in PC-3 human prostate cancer cells in vivo. It turned out that five lysine residues in HMGA1a, i.e., Lys-14, Lys-64, Lys-66, Lys-70, and Lys-73, could be acetylated by both p300 and PCAF. We further quantified the level of acetylation by analyzing, with LC-MS/MS, the proteolytic peptides of the in vitro or in vivo acetylated HMGA1 proteins where the unmodified lysine residues were chemically derivatized with a perdeuterated acetyl group. Quantification results revealed that p300 and PCAF exhibited different site preferences for the acetylation; the preference of p300 acetylation followed the order of Lys-64 approximately Lys-70 > Lys-66 > Lys-14 approximately Lys73, whereas the selectivity of PCAF acetylation followed the sequence of Lys-70 approximately Lys-73 > Lys-64 approximately Lys-66 > Lys-14. HMGA1b was acetylated in a very similar fashion as HMGA1a. We also demonstrated that C-terminal phosphorylation of HMGA1 proteins did not affect the in vitro acetylation of the two proteins by either p300 or PCAF. Moreover, we examined the acetylation of lysine residues in HMGA1a and HMGA1b isolated from PC-3 human prostate cancer cells. Our results showed that all the above five lysine residues were also acetylated in vivo, with Lys-64, Lys-66 and Lys-70 in HMGA1a exhibiting higher levels of acetylation than Lys-14 and Lys-73.
Collapse
Affiliation(s)
| | | | | | | | - Yinsheng Wang
- *Address correspondence to: Yinsheng Wang, E-mail: , Fax: (951) 827-4713, Tel: (951) 827-2700
| |
Collapse
|
12
|
Zou Y, Webb K, Perna AD, Zhang Q, Clarke S, Wang Y. A Mass Spectrometric Study on the in Vitro Methylation of HMGA1a and HMGA1b Proteins by PRMTs: Methylation Specificity, the Effect of Binding to AT-Rich Duplex DNA, and the Effect of C-Terminal Phosphorylation. Biochemistry 2007; 46:7896-906. [PMID: 17550233 DOI: 10.1021/bi6024897] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
HMGA1a and HMGA1b are members of one subfamily of non-histone chromosomal high-mobility group (HMG) proteins. They bind to various DNA-related substrates, including the minor groove of AT-rich duplex DNA sequences, and have been postulated to be architectural transcription factors functioning in a wide variety of cellular processes. Post-translational modifications of HMGA1 proteins, such as phosphorylation, acetylation, and methylation, are widely observed in tumor cells in vivo and correlated with the modulation of protein function. Here, we investigated the in vitro methylation of recombinant human HMGA1a and HMGA1b proteins by three members of the protein arginine methyltransferase (PRMT) family: PRMT1, PRMT3, and PRMT6. PRMT1 and PRMT3 showed a preference for methylating arginine residues in the first AT-hook of HMGA1 proteins, whereas PRMT6 methylated mainly residues in the second AT-hook. The initial sites of methylation catalyzed by PRMT1 and PRMT3 were mapped by tandem mass spectrometry to be Arg25 and Arg23, respectively, while we confirmed that the initial sites of methylation catalyzed by PRMT6 were at Arg57 and Arg59. Our results also revealed that binding of HMGA1 proteins to AT-rich duplex DNA, but not GC-rich duplex DNA, significantly inhibited the methylation efficiency of all of the PRMTs toward HMGA1 proteins. Moreover, C-terminal constitutive phosphorylation of HMGA1 proteins induced by protein kinase CK2 did not have any appreciable effect on the in vitro methylation of HMGA1. Our results suggest that PRMT1 might be involved in the previously reported methylation of Arg25 in HMGA1a in vivo.
Collapse
Affiliation(s)
- Yan Zou
- Department of Chemistry-027, University of California, Riverside, California 92521-0403, USA
| | | | | | | | | | | |
Collapse
|
13
|
Kjærulff S, Andersen NR, Borup MT, Nielsen O. Cdk phosphorylation of the Ste11 transcription factor constrains differentiation-specific transcription to G1. Genes Dev 2007; 21:347-59. [PMID: 17289922 PMCID: PMC1785116 DOI: 10.1101/gad.407107] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Eukaryotic cells normally differentiate from G(1); here we investigate the mechanism preventing expression of differentiation-specific genes outside G(1). In fission yeast, induction of the transcription factor Ste11 triggers sexual differentiation. We find that Ste11 is only active in G(1) when Cdk activity is low. In the remaining part of the cell cycle, Ste11 becomes Cdk-phosphorylated at Thr 82 (T82), which inhibits its DNA-binding activity. Since the ste11 gene is autoregulated and the Ste11 protein is highly unstable, this Cdk switch rapidly extinguishes Ste11 activity when cells enter S phase. When we mutated T82 to aspartic acid, mimicking constant phosphorylation, cells no longer underwent differentiation. Conversely, changing T82 to alanine rendered Ste11-controlled transcription constitutive through the cell cycle, and allowed mating from S phase with increased frequency. Thus, Cdk phosphorylation mediates periodic expression of Ste11 and its target genes, and we suggest this to be part of the mechanism restricting differentiation to G(1).
Collapse
Affiliation(s)
- Søren Kjærulff
- Institute of Molecular Biology and Physiology, University of Copenhagen, DK-1353 Copenhagen K, Denmark
| | - Nicoline Resen Andersen
- Institute of Molecular Biology and Physiology, University of Copenhagen, DK-1353 Copenhagen K, Denmark
| | - Mia Trolle Borup
- Institute of Molecular Biology and Physiology, University of Copenhagen, DK-1353 Copenhagen K, Denmark
| | - Olaf Nielsen
- Institute of Molecular Biology and Physiology, University of Copenhagen, DK-1353 Copenhagen K, Denmark
- Corresponding author.E-MAIL ; FAX 45-35322113
| |
Collapse
|
14
|
Cui T, Wei S, Brew K, Leng F. Energetics of binding the mammalian high mobility group protein HMGA2 to poly(dA-dT)2 and poly(dA)-poly(dT). J Mol Biol 2005; 352:629-45. [PMID: 16109425 DOI: 10.1016/j.jmb.2005.07.048] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2005] [Revised: 07/14/2005] [Accepted: 07/18/2005] [Indexed: 11/18/2022]
Abstract
The mammalian high mobility group protein A2 (HMGA2) is a chromosomal architectural transcription factor involved in oncogenesis and cell transformation. It has three "AT-hook" DNA binding domains, which specifically bind to the minor groove of AT DNAs. The interaction of HMGA2 with poly(dA-dT)2 and poly(dA)poly(dT) has been investigated using the ethidium displacement assay, isothermal titration calorimetry, and UV melting studies. Each AT hook DNA binding domain was found to bind to 5 bp and each HMGA2 molecule binds to 15 bp. Although an individual AT hook DNA binding domain binds to AT DNAs with moderate affinity, HMGA2 binds with very high affinity to both DNAs in solutions containing 20 mM Na+ at 25 degrees C. The K(a) and binding enthalpy for poly(dA-dT)2 were determined to be, respectively, 1.9x10(14)M(-1) and -29.1(+/-0.5)kcal/mol. The binding reaction is enthalpy-driven with a favorable free energy of -19.5 kcal/mol and unfavorable entropy of -32.5 cal/mol K (-TDeltaS= +9. 7kcal/mol) at a 1M reference state. Interestingly, although HMGA2 binds to poly(dA)poly(dT) with a binding constant of 9.6x10(12) M(-1), the binding reaction is entropy-driven with an unfavorable enthalpy of +0.6 kcal/mol, a free energy of -17.7 kcal/mol and an entropy of +61.4 cal/mol K (-TDeltaS=-18.3 kcal/mol) at the 1 M state. The enthalpy-entropy compensation is similar to that of several minor groove-binding drugs such as netropesin, distamycin A and Hoechst33258 and may be a reflection of dehydration difference of different ligand-DNA complexes. The salt-dependence of the binding constant of HMGA2 with both DNAs showed that electrostatic interaction is a dominant force for the binding reactions. The temperature dependence of binding enthalpy for poly(dA-dT)2 indicates a large heat capacity of binding of -705(+/-113) cal/molK, consistent with an important role of solvent displacement in the linked folding/binding processes in this system.
Collapse
Affiliation(s)
- Tengjiao Cui
- Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA
| | | | | | | |
Collapse
|
15
|
Sgarra R, Rustighi A, Tessari MA, Di Bernardo J, Altamura S, Fusco A, Manfioletti G, Giancotti V. Nuclear phosphoproteins HMGA and their relationship with chromatin structure and cancer. FEBS Lett 2004; 574:1-8. [PMID: 15358530 DOI: 10.1016/j.febslet.2004.08.013] [Citation(s) in RCA: 152] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Revised: 07/23/2004] [Accepted: 08/02/2004] [Indexed: 01/09/2023]
Abstract
The structural characteristics of the three nuclear phosphoproteins of the high mobility group A family are outlined and related to their participation in chromatin structure alteration in many biological processes such as gene expression, neoplastic transformation, differentiation, and apoptosis. The elevated expression of these proteins in tumor cells and their post-translational modifications, such as phosphorylation, acetylation and methylation, are discussed and suggested as suitable targets for cancer chemotherapy.
Collapse
Affiliation(s)
- Riccardo Sgarra
- Dipartimento di Biochimica, Biofisica e Chimica delle Macromolecole, via L. Giorgieri 1, Università di Trieste, 34127 Trieste, Italy
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Di Agostino S, Fedele M, Chieffi P, Fusco A, Rossi P, Geremia R, Sette C. Phosphorylation of high-mobility group protein A2 by Nek2 kinase during the first meiotic division in mouse spermatocytes. Mol Biol Cell 2003; 15:1224-32. [PMID: 14668482 PMCID: PMC363112 DOI: 10.1091/mbc.e03-09-0638] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The mitogen-activated protein kinase (MAPK) pathway is required for maintaining the chromatin condensed during the two meiotic divisions and to avoid a second round of DNA duplication. However, molecular targets of the MAPK pathway on chromatin have not yet been identified. Here, we show that the architectural chromatin protein HMGA2 is highly expressed in male meiotic cells. Furthermore, Nek2, a serine-threonine kinase activated by the MAPK pathway in mouse pachytene spermatocytes, directly interacts with HMGA2 in vitro and in mouse spermatocytes. The interaction does not depend on the activity of Nek2 and seems constitutive. On progression from pachytene to metaphase, Nek2 is activated and HMGA2 is phosphorylated in an MAPK-dependent manner. We also show that Nek2 phosphorylates in vitro HMGA2 and that this phosphorylation decreases the affinity of HMGA2 for DNA and might favor its release from the chromatin. Indeed, we find that most HMGA2 associates with chromatin in mouse pachytene spermatocytes, whereas it is excluded from the chromatin upon the G2/M progression. Because hmga2-/- mice are sterile and show a dramatic impairment of spermatogenesis, it is possible that the functional interaction between HMGA2 and Nek2 plays a crucial role in the correct process of chromatin condensation in meiosis.
Collapse
Affiliation(s)
- Silvia Di Agostino
- Dipartimento di Sanità Pubblica e Biologia Cellulare, University of Rome "Tor Vergata," 00133 Rome, Italy
| | | | | | | | | | | | | |
Collapse
|
17
|
Borrmann L, Schwanbeck R, Heyduk T, Seebeck B, Rogalla P, Bullerdiek J, Wisniewski JR. High mobility group A2 protein and its derivatives bind a specific region of the promoter of DNA repair gene ERCC1 and modulate its activity. Nucleic Acids Res 2003; 31:6841-51. [PMID: 14627817 PMCID: PMC290254 DOI: 10.1093/nar/gkg884] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2003] [Revised: 10/07/2003] [Accepted: 10/07/2003] [Indexed: 12/13/2022] Open
Abstract
High mobility group A2 (HMGA2) chromosomal non-histone protein and its derivatives play an important role in development and progression of benign and malignant tumors, obesity and arteriosclerosis, although the underlying mechanisms of these conditions are poorly understood. Therefore, we tried to identify target genes for this transcriptional regulator and to provide insights in the mechanism of interaction to its target. Multiple genes have been identified by microarray experiments as being transcriptionally regulated by HMGA2. Among these we chose the ERCC1 gene, encoding a DNA repair protein, for this study. DNA-binding studies were performed using HMGA2 and C-terminally truncated DeltaHMGA2, a derivative that is frequently observed in a variety of tumors. A unique high affinity HMGA2 binding site was mapped to a specific AT-rich region located -323 to -298 upstream of the ERCC1 transcription start site, distinguishing it from other potential AT-rich binding sites. The observed 1:1 stoichiometry for the binding of wild-type HMGA2 to this region was altered to 1:2 upon binding of truncated DeltaHMGA2, causing DNA bending. Furthermore, the regulatory effect of HMGA2 was confirmed by luciferase promoter assays showing that ERCC1 promoter activity is down-regulated by all investigated HMGA2 forms, with the most striking effect exerted by DeltaHMGA2. Our results provide the first insights into how HMGA2 and its aberrant forms bind and regulate the ERCC1 promoter.
Collapse
Affiliation(s)
- Lars Borrmann
- Center for Human Genetics, University of Bremen, Leobenerstr. ZHG, D-28359 Bremen, Germany
| | | | | | | | | | | | | |
Collapse
|
18
|
Vasseur S, Hoffmeister A, Garcia-Montero A, Barthet M, Saint-Michel L, Berthézène P, Fiedler F, Closa D, Dagorn JC, Iovanna JL. Mice with targeted disruption of p8 gene show increased sensitivity to lipopolysaccharide and DNA microarray analysis of livers reveals an aberrant gene expression response. BMC Gastroenterol 2003; 3:25. [PMID: 12959645 PMCID: PMC212298 DOI: 10.1186/1471-230x-3-25] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2003] [Accepted: 09/08/2003] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND p8 is a DNA-binding protein induced in many tissues in response to LPS treatment. Hence, p8 could be a mediator of LPS-associated effects or, on the contrary, p8 expression may be part of the protective mechanism of the tissues in response to LPS. Finally, p8 expression in response to LPS could also be a simple epiphenomenon. METHODS To investigate the role of p8 in vivo, we generated p8-deficient mice by gene targeting. Because p8 is a stress protein, we analyzed the response of p8-/- mice to a systemic stress induced by LPS injection. Liver was chosen as model organ to monitor alterations in gene expression. RESULTS LPS resulted in higher serum TNF-alpha concentration and higher mortality rate in p8-deficient mice than in wild-type. Also, liver and pancreas, but not lung, from p8-/- mice showed increased amounts of MPO and HPO. To gain insight into the molecular bases of such susceptibility, we used high density DNA microarrays consisting of ~6000 genes and ESTs to compare gene regulation in response to LPS in p8+/+ and p8-/- livers. In wild-type, 105 genes and 73 ESTs were up-regulated and 232 genes and 138 ESTs down-regulated. By contrast, 212 genes and 125 ESTs were found up-regulated and 90 genes and 85 ESTs down regulated in p8-/- mice. Among them, only 93 (51 induced and 42 repressed) corresponded to the wild-type pattern, demonstrating that p8 deficiency hinders the normal response to LPS, which may account for the increased sensitivity of p8-/-mice to the endotoxin. CONCLUSIONS The large number of genes showing abnormal regulation after LPS suggests that p8 is an important regulatory factor involved in many cellular defence pathways.
Collapse
Affiliation(s)
- Sophie Vasseur
- Centre de Recherche INSERM, EMI 0116, 163 Avenue de Luminy, 13009 Marseille, France
| | - Albrecht Hoffmeister
- Centre de Recherche INSERM, EMI 0116, 163 Avenue de Luminy, 13009 Marseille, France
| | | | - Marc Barthet
- Centre de Recherche INSERM, EMI 0116, 163 Avenue de Luminy, 13009 Marseille, France
| | - Laure Saint-Michel
- Centre de Recherche INSERM, EMI 0116, 163 Avenue de Luminy, 13009 Marseille, France
| | - Patrice Berthézène
- Centre de Recherche INSERM, EMI 0116, 163 Avenue de Luminy, 13009 Marseille, France
| | - Fritz Fiedler
- Institut für Anästhesie, Klinikum Mannheim, Theodor-Kutzer-Ufer, D-68167, Mannheim, Germany
| | - Daniel Closa
- Department of Experimental Pathology. IDIBAPS; IIBB-CSIC, 08036 Barcelona, Spain
| | - Jean Charles Dagorn
- Centre de Recherche INSERM, EMI 0116, 163 Avenue de Luminy, 13009 Marseille, France
| | - Juan Lucio Iovanna
- Centre de Recherche INSERM, EMI 0116, 163 Avenue de Luminy, 13009 Marseille, France
| |
Collapse
|
19
|
Liu F, Chau KY, Arlotta P, Ono SJ. The HMG I proteins: dynamic roles in gene activation, development, and tumorigenesis. Immunol Res 2002; 24:13-29. [PMID: 11485207 DOI: 10.1385/ir:24:1:13] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
The high mobility group I, Y, and I-C proteins are low-molecular-weight, nonhistone chromosomal proteins that play a general role modulating gene expression during development and the immune response. Consistent with their role in early development, all three proteins are expressed at high levels during embryogenesis, and their expression is markedly diminished in differentiated cells. Exceptions to the general repression of these genes in adult tissues involve (1) A burst of synthesis of the HMG I protein during the immune response (during lymphocyte activation and preceding cytokine/adhesion molecule gene expression), (2) A constitutive expression of the HMG I and Y proteins in photoreceptor cells, and (3) Derepression of HMG I, Y, and often I-C expression in neoplastic cells. Work from several laboratories has now uncovered how these proteins participate in gene activation: (1) By altering the chromatin structure around an inducible gene-and thus influencing accessibility of the locus to regulatory proteins-(2) By facilitating the loading of transcription factors onto the promoters, and (3) By bridging adjacent transcription factors on a promoter via protein/protein interactions. Despite the similar structures and biochemical properties of the three proteins, the work has also provided clues to a division of labor between these proteins. HMG I and Y have demonstrable roles in enhanceosome formation, whereas HMG I-C has a specific role in adipogenesis. C-terminal truncations of HMG I-C and wild-type HMG Y appear to function in a manner analogous to oncogenes, as assessed by cellular transforation assays and transgenic mice. Future work should clearly define the similarities and differences in the biological roles of the three proteins, and should evolve to include attempts at pharmaceutical intervention in disease, based upon structural information concerning HMG I interactions with DNA and with regulatory proteins.
Collapse
Affiliation(s)
- F Liu
- University College London, Institute of Ophthalmology, UK
| | | | | | | |
Collapse
|
20
|
Ko L, Cardona GR, Henrion-Caude A, Chin WW. Identification and characterization of a tissue-specific coactivator, GT198, that interacts with the DNA-binding domains of nuclear receptors. Mol Cell Biol 2002; 22:357-69. [PMID: 11739747 PMCID: PMC134202 DOI: 10.1128/mcb.22.1.357-369.2002] [Citation(s) in RCA: 74] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gene activation mediated by nuclear receptors is regulated in a tissue-specific manner and requires interactions between nuclear receptors and their cofactors. Here, we identified and characterized a tissue-specific coactivator, GT198, that interacts with the DNA-binding domains of nuclear receptors. GT198 was originally described as a genomic transcript that mapped to the human breast cancer susceptibility locus 17q12-q21 with unknown function. We show that GT198 exhibits a tissue-specific expression pattern in which its mRNA is elevated in testis, spleen, thymus, pituitary cells, and several cancer cell lines. GT198 is a 217-amino-acid nuclear protein that contains a leucine zipper required for its dimerization. In vitro binding and yeast two-hybrid assays indicated that GT198 interacted with nuclear receptors through their DNA-binding domains. GT198 potently stimulated transcription mediated by estrogen receptor alpha and beta, thyroid hormone receptor beta1, androgen receptor, glucocorticoid receptor, and progesterone receptor. However, the action of GT198 was distinguishable from that of the ligand-binding domain-interacting nuclear receptor coactivators, such as TRBP, CBP, and SRC-1, with respect to basal activation and hormone sensitivity. Furthermore, protein kinase A, protein kinase C, and mitogen-activated protein kinase can phosphorylate GT198 in vitro, and cotransfection of these kinases regulated the transcriptional activity of GT198. These data suggest that GT198 is a tissue-specific, kinase-regulated nuclear receptor coactivator that interacts with the DNA-binding domains of nuclear receptors.
Collapse
Affiliation(s)
- Lan Ko
- Department of Gene Regulation, Bone and Inflammation Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA.
| | | | | | | |
Collapse
|
21
|
Schwanbeck R, Gymnopoulos M, Petry I, Piekiełko A, Szewczuk Z, Heyduk T, Zechel K, Wiśniewski JR. Consecutive steps of phosphorylation affect conformation and DNA binding of the chironomus high mobility group A protein. J Biol Chem 2001; 276:26012-21. [PMID: 11335713 DOI: 10.1074/jbc.m011053200] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The high mobility group (HMG) proteins of the AT-hook family (HMGA) lie downstream in regulatory networks with protein kinase C, Cdc2 kinase, MAP kinase, and casein kinase 2 (CK2) as final effectors. In the cells of the midge Chironomus, almost all of the HMGA protein (cHMGA) is phosphorylated by CK2 at two adjacent sites. 40% of the protein population is additionally modified by MAP kinase. Using spectroscopic and protein footprinting techniques, we analyzed how individual and consecutive steps of phosphorylation change the conformation of an HMGA protein and affect its contacts with poly(dA-dT).poly(dA-dT) and a fragment of the interferon-beta promoter. We demonstrate that phosphorylation of cHMGA by CK2 alters its conformation and modulates its DNA binding properties such that a subsequent phosphorylation by Cdc2 kinase changes the organization of the protein-DNA complex. In contrast, consecutive phosphorylation by MAP kinase, which results in a dramatic change in cHMGA conformation, has no direct effect on the complex. Because the phosphorylation of the HMGA proteins attenuates binding affinity and reduces the extent of contacts between the DNA and protein, it is likely that this process mirrors the dynamics and diversity of regulatory processes in chromatin.
Collapse
Affiliation(s)
- R Schwanbeck
- III. Zoologisches Institut-Entwicklungsbiologie, Universität Göttingen, Göttingen D 37073, Germany
| | | | | | | | | | | | | | | |
Collapse
|