1
|
Jackson JT, Nutt SL, McCormack MP. The Haematopoietically-expressed homeobox transcription factor: roles in development, physiology and disease. Front Immunol 2023; 14:1197490. [PMID: 37398663 PMCID: PMC10313424 DOI: 10.3389/fimmu.2023.1197490] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 06/01/2023] [Indexed: 07/04/2023] Open
Abstract
The Haematopoietically expressed homeobox transcription factor (Hhex) is a transcriptional repressor that is of fundamental importance across species, as evident by its evolutionary conservation spanning fish, amphibians, birds, mice and humans. Indeed, Hhex maintains its vital functions throughout the lifespan of the organism, beginning in the oocyte, through fundamental stages of embryogenesis in the foregut endoderm. The endodermal development driven by Hhex gives rise to endocrine organs such as the pancreas in a process which is likely linked to its role as a risk factor in diabetes and pancreatic disorders. Hhex is also required for the normal development of the bile duct and liver, the latter also importantly being the initial site of haematopoiesis. These haematopoietic origins are governed by Hhex, leading to its crucial later roles in definitive haematopoietic stem cell (HSC) self-renewal, lymphopoiesis and haematological malignancy. Hhex is also necessary for the developing forebrain and thyroid gland, with this reliance on Hhex evident in its role in endocrine disorders later in life including a potential role in Alzheimer's disease. Thus, the roles of Hhex in embryological development throughout evolution appear to be linked to its later roles in a variety of disease processes.
Collapse
Affiliation(s)
- Jacob T. Jackson
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
| | - Stephen L. Nutt
- Immunology Division, The Walter and Eliza Hall Institute of Medical Research, Parkville, VIC, Australia
- Department of Medical Biology, University of Melbourne, Parkville, VIC, Australia
| | - Matthew P. McCormack
- The Australian Centre for Blood Diseases, Monash University, Melbourne, VIC, Australia
- iCamuno Biotherapeutics, Melbourne, VIC, Australia
| |
Collapse
|
2
|
Reolizo LM, Williams H, Wadey K, Frankow A, Li Z, Gaston K, Jayaraman PS, Johnson JL, George SJ. Inhibition of Intimal Thickening By PRH (Proline-Rich Homeodomain) in Mice. Arterioscler Thromb Vasc Biol 2023; 43:456-473. [PMID: 36700427 PMCID: PMC9944393 DOI: 10.1161/atvbaha.122.318367] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2022] [Accepted: 01/05/2023] [Indexed: 01/27/2023]
Abstract
BACKGROUND Late vein graft failure is caused by intimal thickening resulting from endothelial cell (EC) damage and inflammation which promotes vascular smooth muscle cell (VSMC) dedifferentiation, migration, and proliferation. Nonphosphorylatable PRH (proline-rich homeodomain) S163C:S177C offers enhanced stability and sustained antimitotic effect. Therefore, we investigated whether adenovirus-delivered PRH S163C:S177C protein attenuates intimal thickening via VSMC phenotype modification without detrimental effects on ECs. METHODS PRH S163C:S177C was expressed in vitro (human saphenous vein-VSMCs and human saphenous vein-ECs) and in vivo (ligated mouse carotid arteries) by adenoviruses. Proliferation, migration, and apoptosis were quantified and phenotype was assessed using Western blotting for contractile filament proteins and collagen gel contraction. EC inflammation was quantified using VCAM (vascular cell adhesion protein)-1, ICAM (intercellular adhesion molecule)-1, interleukin-6, and monocyte chemotactic factor-1 measurement and monocyte adhesion. Next Generation Sequencing was utilized to identify novel downstream mediators of PRH action and these and intimal thickening were investigated in vivo. RESULTS PRH S163C:S177C inhibited proliferation, migration, and apoptosis and promoted contractile phenotype (enhanced contractile filament proteins and collagen gel contraction) compared with virus control in human saphenous vein-VSMCs. PRH S163C:S177C expression in human saphenous vein-ECs significantly reduced apoptosis, without affecting cell proliferation and migration, while reducing TNF (tumor necrosis factor)-α-induced VCAM-1 and ICAM-1 and monocyte adhesion and suppressing interleukin-6 and monocyte chemotactic factor-1 protein levels. PRH S163C:S177C expression in ligated murine carotid arteries significantly impaired carotid artery ligation-induced neointimal proliferation and thickening without reducing endothelial coverage. Next Generation Sequencing revealed STAT-1 (signal transducer and activator of transcription 1) and HDAC-9 (histone deacetylase 9) as mediators of PRH action and was supported by in vitro and in vivo analyses. CONCLUSIONS We observed PRH S163C:S177C attenuated VSMC proliferation, and migration and enhanced VSMC differentiation at least in part via STAT-1 and HDAC-9 signaling while promoting endothelial repair and anti-inflammatory properties. These findings highlight the potential for PRH S163C:S177C to preserve endothelial function whilst suppressing intimal thickening, and reducing late vein graft failure.
Collapse
Affiliation(s)
- Lien M. Reolizo
- Bristol Heart Institute, University of Bristol, UK (L.M.R., H.W., K.W., A.F., Z.L., J.L.J., S.J.G.)
| | - Helen Williams
- Bristol Heart Institute, University of Bristol, UK (L.M.R., H.W., K.W., A.F., Z.L., J.L.J., S.J.G.)
| | - Kerry Wadey
- Bristol Heart Institute, University of Bristol, UK (L.M.R., H.W., K.W., A.F., Z.L., J.L.J., S.J.G.)
| | - Aleksandra Frankow
- Bristol Heart Institute, University of Bristol, UK (L.M.R., H.W., K.W., A.F., Z.L., J.L.J., S.J.G.)
| | - Ze Li
- Bristol Heart Institute, University of Bristol, UK (L.M.R., H.W., K.W., A.F., Z.L., J.L.J., S.J.G.)
| | - Kevin Gaston
- School of Medicine and Biodiscovery Institute, Faculty of Medicine & Health Sciences, University of Nottingham, UK (K.G., P.-S.J.)
| | - Padma-Sheela Jayaraman
- School of Medicine and Biodiscovery Institute, Faculty of Medicine & Health Sciences, University of Nottingham, UK (K.G., P.-S.J.)
| | - Jason L. Johnson
- Bristol Heart Institute, University of Bristol, UK (L.M.R., H.W., K.W., A.F., Z.L., J.L.J., S.J.G.)
| | - Sarah J. George
- Bristol Heart Institute, University of Bristol, UK (L.M.R., H.W., K.W., A.F., Z.L., J.L.J., S.J.G.)
| |
Collapse
|
3
|
Niu K, Meng Y, Liu M, Ma Z, Lin H, Zhou H, Fan H. Phosphorylation of GntR reduces Streptococcus suis oxidative stress resistance and virulence by inhibiting NADH oxidase transcription. PLoS Pathog 2023; 19:e1011227. [PMID: 36913374 PMCID: PMC10010549 DOI: 10.1371/journal.ppat.1011227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Accepted: 02/21/2023] [Indexed: 03/14/2023] Open
Abstract
GntR transcription factor of Streptococcus suis serotype 2 (SS2) is a potential substrate protein of STK, but the regulation mechanisms of GntR phosphorylation are still unclear. This study confirmed that STK phosphorylated GntR in vivo, and in vitro phosphorylation experiments showed that STK phosphorylated GntR at Ser-41. The phosphomimetic strain (GntR-S41E) had significantly reduced lethality in mice and reduced bacterial load in the blood, lung, liver, spleen, and brain of infected mice compared to wild-type (WT) SS2. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) experiments demonstrated that the promoter of nox was bound by GntR. The phosphomimetic protein GntR-S41E cannot bind to the promoter of nox, and the nox transcription levels were significantly reduced in the GntR-S41E mutant compared to WT SS2. The virulence in mice and the ability to resist oxidative stress of the GntR-S41E strain were restored by complementing transcript levels of nox. NOX is an NADH oxidase that catalyzes the oxidation of NADH to NAD+ with the reduction of oxygen to water. We found that NADH is likely accumulated under oxidative stress in the GntR-S41E strain, and higher NADH levels resulted in increased amplified ROS killing. In total, we report GntR phosphorylation could inhibit the transcription of nox, which impaired the ability of SS2 to resist oxidative stress and virulence.
Collapse
Affiliation(s)
- Kai Niu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Yu Meng
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Mingxing Liu
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
| | - Zhe Ma
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Huixing Lin
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Hong Zhou
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| | - Hongjie Fan
- MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, China
- Jiangsu Co-innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, Yangzhou University, Yangzhou, China
| |
Collapse
|
4
|
Guo Y, Zhu Z, Huang Z, Cui L, Yu W, Hong W, Zhou Z, Du P, Liu CY. CK2-induced cooperation of HHEX with the YAP-TEAD4 complex promotes colorectal tumorigenesis. Nat Commun 2022; 13:4995. [PMID: 36008411 PMCID: PMC9411202 DOI: 10.1038/s41467-022-32674-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2021] [Accepted: 08/11/2022] [Indexed: 11/23/2022] Open
Abstract
Dysregulation of Hippo pathway leads to hyperactivation of YAP-TEAD transcriptional complex in various cancers, including colorectal cancer (CRC). In this study, we observed that HHEX (Hematopoietically expressed homeobox) may enhance transcription activity of the YAP-TEAD complex. HHEX associates with and stabilizes the YAP-TEAD complex on the regulatory genomic loci to coregulate the expression of a group of YAP/TEAD target genes. Also, HHEX may indirectly regulate these target genes by controlling YAP/TAZ expression. Importantly, HHEX is required for the pro-tumorigenic effects of YAP during CRC progression. In response to serum stimulation, CK2 (Casein Kinase 2) phosphorylates HHEX and enhances its interaction with TEAD4. A CK2 inhibitor CX-4945 diminishes the interaction between HHEX and TEAD4, leading to decreased expression of YAP/TEAD target genes. CX-4945 synergizes the antitumor activity of YAP-TEAD inhibitors verteporfin and Super-TDU. Elevated expression of HHEX is correlated with hyperactivation of YAP/TEAD and associated with poor prognosis of CRC patients. Overall, our study identifies HHEX as a positive modulator of YAP/TEAD to promote colorectal tumorigenesis, providing a new therapeutic strategy for targeting YAP/TEAD in CRC. Hippo signalling is often deregulated in cancers. Here the authors show that CK2 enhances the cooperation of HHEX with YAP-TEAD complex to promote colorectal tumorigenesis.
Collapse
Affiliation(s)
- Yuegui Guo
- Department of Colorectal and Anal Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.,Shanghai Colorectal Cancer Research Center, Shanghai, 200092, China
| | - Zhehui Zhu
- Department of Colorectal and Anal Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.,Shanghai Colorectal Cancer Research Center, Shanghai, 200092, China.,State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, 200438, China
| | - Zhenyu Huang
- Department of Colorectal and Anal Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.,Shanghai Colorectal Cancer Research Center, Shanghai, 200092, China
| | - Long Cui
- Department of Colorectal and Anal Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China.,Shanghai Colorectal Cancer Research Center, Shanghai, 200092, China
| | - Wei Yu
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, 200438, China
| | - Wanjin Hong
- Institute of Molecular and Cell Biology, Agency for Science, Technology and Research (A*STAR), 61, Biopolis Drive, Proteos, Singapore, 138673, Singapore
| | - Zhaocai Zhou
- State Key Laboratory of Genetic Engineering, School of Life Sciences, Zhongshan Hospital, Fudan University, Shanghai, 200438, China.
| | - Peng Du
- Department of Colorectal and Anal Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China. .,Shanghai Colorectal Cancer Research Center, Shanghai, 200092, China.
| | - Chen-Ying Liu
- Department of Colorectal and Anal Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, 200092, China. .,Shanghai Colorectal Cancer Research Center, Shanghai, 200092, China.
| |
Collapse
|
5
|
Firnau MB, Brieger A. CK2 and the Hallmarks of Cancer. Biomedicines 2022; 10:1987. [PMID: 36009534 PMCID: PMC9405757 DOI: 10.3390/biomedicines10081987] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 08/08/2022] [Accepted: 08/10/2022] [Indexed: 11/29/2022] Open
Abstract
Cancer is a leading cause of death worldwide. Casein kinase 2 (CK2) is commonly dysregulated in cancer, impacting diverse molecular pathways. CK2 is a highly conserved serine/threonine kinase, constitutively active and ubiquitously expressed in eukaryotes. With over 500 known substrates and being estimated to be responsible for up to 10% of the human phosphoproteome, it is of significant importance. A broad spectrum of diverse types of cancer cells has been already shown to rely on disturbed CK2 levels for their survival. The hallmarks of cancer provide a rationale for understanding cancer's common traits. They constitute the maintenance of proliferative signaling, evasion of growth suppressors, resisting cell death, enabling of replicative immortality, induction of angiogenesis, the activation of invasion and metastasis, as well as avoidance of immune destruction and dysregulation of cellular energetics. In this work, we have compiled evidence from the literature suggesting that CK2 modulates all hallmarks of cancer, thereby promoting oncogenesis and operating as a cancer driver by creating a cellular environment favorable to neoplasia.
Collapse
Affiliation(s)
| | - Angela Brieger
- Department of Internal Medicine I, Biomedical Research Laboratory, University Hospital Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| |
Collapse
|
6
|
Jayaraman PS, Gaston K. Targeting protein kinase CK2 in the treatment of cholangiocarcinoma. EXPLORATION OF TARGETED ANTI-TUMOR THERAPY 2021; 2:434-447. [PMID: 36045705 PMCID: PMC9400764 DOI: 10.37349/etat.2021.00055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Accepted: 08/31/2021] [Indexed: 12/23/2022] Open
Abstract
Cholangiocarcinoma (CCA) is a disease with a very poor prognosis and limited treatment options. Although targeted therapies directed towards specific mutations found in CCA are becoming available and are showing great potential, many tumors do not carry actionable mutations and, in those that do, the emergence of drug resistance is a likely consequence of treatment. Therapeutic targeting of enzymes and other proteins that show elevated activity in CCA cells but which are not altered by mutation is a potential strategy for the treatment of target negative and drug-resistant disease. Protein kinase CK2 (CK2) is a ubiquitously expressed kinase that has increased expression and increased activity in a variety of cancer types including CCA. Several potent CK2 inhibitors are in pre-clinical development or under assessment in a variety of clinical trials often in combination with drugs that induce DNA damage. This review outlines the importance of CK2 in CCA and assesses the progress that has been made in the evaluation of CK2 inhibition as a treatment strategy in this disease. Targeting CK2 based on the expression levels or activity of this protein and/or in combination with drugs that induce DNA damage or inhibit cell cycle progression, could be a viable option for tumors that lack actionable mutations, or for tumors that develop resistance to targeted treatments.
Collapse
Affiliation(s)
- Padma-Sheela Jayaraman
- Biodiscovery Institute, University of Nottingham, NG7 2UH, UK
- Division of Translational Medical Sciences, School of Medicine, University of Nottingham, NG7 2UH, UK
| | - Kevin Gaston
- Biodiscovery Institute, University of Nottingham, NG7 2UH, UK
- Division of Translational Medical Sciences, School of Medicine, University of Nottingham, NG7 2UH, UK
| |
Collapse
|
7
|
Identification and validation of the phosphorylation sites on Aristaless-related homeobox protein. Biosci Rep 2021; 40:225651. [PMID: 32608477 PMCID: PMC7364481 DOI: 10.1042/bsr20194513] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 06/21/2020] [Accepted: 06/29/2020] [Indexed: 11/17/2022] Open
Abstract
The Aristaless-related homeobox protein (ARX) is a transcription factor expressed in the developing forebrain, skeletal muscle, pancreas, testis, and a variety of other tissues. It is known to have context-dependent transcriptional activator and repressor activity, although how it can achieve these opposing functions remains poorly understood. We hypothesized phosphorylation status might play a role in pivoting ARX between functioning as an activator or repressor. To gain further mechanistic insight as to how ARX functions, we identified multiple phosphorylation sites on ARX. We further established PKA as the kinase that phosphorylates ARX at least at Ser266 in mice. Two other kinases, CK2α and CDK4/cyclin D1, were also identified as kinases that phosphorylate ARX in vitro. Unexpectedly, phosphorylation status did not change either the nuclear localization or transcriptional function of ARX.
Collapse
|
8
|
Mullin NP, Varghese J, Colby D, Richardson JM, Findlay GM, Chambers I. Phosphorylation of NANOG by casein kinase I regulates embryonic stem cell self-renewal. FEBS Lett 2021; 595:14-25. [PMID: 33107035 PMCID: PMC7839479 DOI: 10.1002/1873-3468.13969] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 10/13/2020] [Accepted: 10/15/2020] [Indexed: 12/24/2022]
Abstract
The self-renewal efficiency of mouse embryonic stem cells (ESCs) is determined by the concentration of the transcription factor NANOG. While NANOG binds thousands of sites in chromatin, the regulatory systems that control DNA binding are poorly characterised. Here, we show that NANOG is phosphorylated by casein kinase I, and identify target residues. Phosphomimetic substitutions at phosphorylation sites within the homeodomain (S130 and S131) have site-specific functional effects. Phosphomimetic substitution of S130 abolishes DNA binding by NANOG and eliminates LIF-independent self-renewal. In contrast, phosphomimetic substitution of S131 enhances LIF-independent self-renewal, without influencing DNA binding. Modelling the DNA-homeodomain complex explains the disparate effects of these phosphomimetic substitutions. These results indicate how phosphorylation may influence NANOG homeodomain interactions that underpin ESC self-renewal.
Collapse
Affiliation(s)
- Nicholas P. Mullin
- Centre for Regenerative MedicineInstitute for Stem Cell ResearchSchool of Biological SciencesUniversity of EdinburghUK
| | - Joby Varghese
- Protein Phosphorylation and Ubiquitylation UnitJames Black CentreSchool of Life SciencesDundeeUK
| | - Douglas Colby
- Centre for Regenerative MedicineInstitute for Stem Cell ResearchSchool of Biological SciencesUniversity of EdinburghUK
| | - Julia M. Richardson
- Institute of Quantitative Biology, Biochemistry and BiotechnologyEdinburghUK
| | - Greg M. Findlay
- Protein Phosphorylation and Ubiquitylation UnitJames Black CentreSchool of Life SciencesDundeeUK
| | - Ian Chambers
- Centre for Regenerative MedicineInstitute for Stem Cell ResearchSchool of Biological SciencesUniversity of EdinburghUK
| |
Collapse
|
9
|
Blood platelets stimulate cancer extravasation through TGFβ-mediated downregulation of PRH/HHEX. Oncogenesis 2020; 9:10. [PMID: 32019914 PMCID: PMC7000753 DOI: 10.1038/s41389-020-0189-0] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 01/07/2020] [Accepted: 01/10/2020] [Indexed: 02/07/2023] Open
Abstract
Cancer cells go through a process known as epithelial–mesenchymal transition (EMT) during which they acquire the ability to migrate and invade extracellular matrix. Some cells also acquire the ability to move across a layer of endothelial cells to enter and exit the bloodstream; intra- and extravasation, respectively. The transcription factor PRH/HHEX (proline-rich homeodomain/haematopoietically expressed homeobox) controls cell proliferation and cell migration/invasion in a range of cell types. Our previous work showed that PRH activity is downregulated in prostate cancer cells owing to increased inhibitory PRH phosphorylation and that this increases cell proliferation and invasion. PRH inhibits migration and invasion by prostate and breast epithelial cells in part by activating the transcription of Endoglin, a transforming growth factor β (TGFβ) co-receptor. Here we show that depletion of PRH in immortalised prostate epithelial cells results in increased extravasation in vitro. We show that blood platelets stimulate extravasation of cells with depleted PRH and that inhibition of TGFβ signalling blocks the effects of platelets on these cells. Moreover, TGFβ induces changes characteristic of EMT including decreased E-Cadherin expression and increased Snail expression. We show that in prostate cells PRH regulates multiple genes involved in EMT and TGFβ signalling. However, both platelets and TGFβ increase PRH phosphorylation. In addition, TGFβ increases binding of its effector pSMAD3 to the PRH/HHEX promoter and downregulates PRH protein and mRNA levels. Thus, TGFβ signalling downregulates PRH activity by multiple mechanisms and induces an EMT that facilitates extravasation and sensitises cells to TGFβ.
Collapse
|
10
|
Yang T, Liu T, Gan J, Yu K, Chen K, Xue W, Lan L, Yang S, Yang CG. Structural Insight into the Mechanism of Staphylococcus aureus Stp1 Phosphatase. ACS Infect Dis 2019; 5:841-850. [PMID: 30868877 DOI: 10.1021/acsinfecdis.8b00316] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Staphylococcus aureus Stp1, which belongs to the bacterial metal-dependent protein phosphatase (PPM) family, is a promising candidate for antivirulence targeting. How Stp1 recognizes the phosphorylated peptide remains unclear, however. In order to investigate the recognition mechanism of Stp1 in depth, we have determined a series of crystal structures of S. aureus Stp1 in different states and the structural complex of Stp1 bound with a phosphorylated peptide His12. Different phosphorylated peptides, including MgrA- and GraR-derived phosphopeptides, are substrates of Stp1, which supports the function of Stp1 as a selective Ser/Thr phosphatase. In addition, interestingly, the crystal structures of R161-Stp1 variants combined with the biochemical activity validations have uncovered that R161 residue plays a key role to control the conformation switches of the flap domain in order to facilitate substrate binding and the dephosphorylation process. Our findings provide crucial structural insight into the molecular mechanism of S. aureus Stp1 phosphatase and reveal the phosphorylated peptides for biochemistry study and inhibitor screening of Stp1.
Collapse
Affiliation(s)
- Teng Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University, 2708 South Huaxi Road, Guiyang, Guizhou 550025, P. R. China
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
| | - Tingting Liu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
- University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Jianhua Gan
- School of Life Sciences, Fudan University, 2005 Songhu Road, Shanghai 200433, P. R. China
| | - Kunqian Yu
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
- University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Kaixian Chen
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
- University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Wei Xue
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University, 2708 South Huaxi Road, Guiyang, Guizhou 550025, P. R. China
| | - Lefu Lan
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
- University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| | - Song Yang
- State Key Laboratory Breeding Base of Green Pesticide and Agricultural Bioengineering, Key Laboratory of Green Pesticide and Agricultural Bioengineering, Ministry of Education, Center for R&D of Fine Chemicals, Guizhou University, 2708 South Huaxi Road, Guiyang, Guizhou 550025, P. R. China
| | - Cai-Guang Yang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, P. R. China
- University of the Chinese Academy of Sciences, 19A Yuquan Road, Beijing 100049, P. R. China
| |
Collapse
|
11
|
Monteiro LF, Forti FL. Network analysis of DUSP12 partners in the nucleus under genotoxic stress. J Proteomics 2019; 197:42-52. [PMID: 30779967 DOI: 10.1016/j.jprot.2019.02.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/23/2019] [Accepted: 02/12/2019] [Indexed: 01/01/2023]
Abstract
Dual Specificity Phosphatase 12 is a member of the Atypical DUSP Protein Tyrosine Phosphatase family, meaning that it does not contain typical MAP kinase targeting motifs, while being able to dephosphorylate tyrosine and serine/threonine residues. DUSP12 contains, apart from its catalytic domain, a zinc finger domain, making it one of the largest DUSPs, which displays strong nuclear expression in several tissues. In this work we identified nuclear targets of DUSP12 in two different cancer cell lines (A549 and MCF-7), challenging them with genotoxic stimuli to observe the effect on the networks and to link existing information about DUSP12 functions to the data obtained though mass spectrometry. We found network connections to the cytoskeleton (e.g. IQGAP1), to the chromatin (e.g. HP1BP3), to the splicing machinery and to the previously known pathway of ribosome maturation (e.g. TCOF1), which draw insight into many of the functions of this phosphatase, much likely connecting it to distinct, previously unknown genomic stability mechanisms.
Collapse
Affiliation(s)
- Lucas Falcão Monteiro
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Fábio Luís Forti
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil.
| |
Collapse
|
12
|
Wadey KS, Brown BA, Sala-Newby GB, Jayaraman PS, Gaston K, George SJ. Protein kinase CK2 inhibition suppresses neointima formation via a proline-rich homeodomain-dependent mechanism. Vascul Pharmacol 2017; 99:34-44. [PMID: 28927755 PMCID: PMC5718878 DOI: 10.1016/j.vph.2017.09.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 09/05/2017] [Accepted: 09/14/2017] [Indexed: 11/19/2022]
Abstract
Neointimal hyperplasia is a product of VSMC replication and consequent accumulation within the blood vessel wall. In this study, we determined whether inhibition of protein kinase CK2 and the resultant stabilisation of proline-rich homeodomain (PRH) could suppress VSMC proliferation. Both silencing and pharmacological inhibition of CK2 with K66 antagonised replication of isolated VSMCs. SiRNA-induced knockdown as well as ectopic overexpression of proline-rich homeodomain indicated that PRH disrupts cell cycle progression. Mutation of CK2 phosphorylation sites Ser163 and Ser177 within the PRH homeodomain enabled prolonged cell cycle arrest by PRH. Concomitant knockdown of PRH and inhibition of CK2 with K66 indicated that the anti-proliferative action of K66 required the presence of PRH. Both K66 and adenovirus-mediated gene transfer of S163C:S177C PRH impaired neointima formation in human saphenous vein organ cultures. Importantly, neither intervention had notable effects on cell cycle progression, cell survival or migration in cultured endothelial cells.
Collapse
MESH Headings
- Animals
- Casein Kinase II/antagonists & inhibitors
- Casein Kinase II/genetics
- Casein Kinase II/metabolism
- Cell Cycle Checkpoints/drug effects
- Cell Proliferation/drug effects
- Cells, Cultured
- Homeodomain Proteins/genetics
- Homeodomain Proteins/metabolism
- Human Umbilical Vein Endothelial Cells/drug effects
- Human Umbilical Vein Endothelial Cells/enzymology
- Humans
- Hyperplasia
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/enzymology
- Muscle, Smooth, Vascular/pathology
- Mutation
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/enzymology
- Myocytes, Smooth Muscle/pathology
- Neointima
- Phosphorylation
- Proline-Rich Protein Domains
- Protein Kinase Inhibitors/pharmacology
- RNA Interference
- Rats
- Saphenous Vein/drug effects
- Saphenous Vein/enzymology
- Saphenous Vein/pathology
- Signal Transduction/drug effects
- Tissue Culture Techniques
- Transcription Factors/genetics
- Transcription Factors/metabolism
- Transfection
Collapse
Affiliation(s)
- K S Wadey
- School of Clinical Sciences, University of Bristol, Research Floor Level 7, Bristol Royal Infirmary, Bristol BS2 8HW, UK; Department of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - B A Brown
- School of Clinical Sciences, University of Bristol, Research Floor Level 7, Bristol Royal Infirmary, Bristol BS2 8HW, UK
| | - G B Sala-Newby
- School of Clinical Sciences, University of Bristol, Research Floor Level 7, Bristol Royal Infirmary, Bristol BS2 8HW, UK
| | - P-S Jayaraman
- Division of Immunity and Infection, College of Medicine, University Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - K Gaston
- Department of Biochemistry, University of Bristol, Bristol BS8 1TD, UK
| | - S J George
- School of Clinical Sciences, University of Bristol, Research Floor Level 7, Bristol Royal Infirmary, Bristol BS2 8HW, UK.
| |
Collapse
|
13
|
Proline-Rich Homeodomain protein (PRH/HHEX) is a suppressor of breast tumour growth. Oncogenesis 2017; 6:e346. [PMID: 28604763 PMCID: PMC5519192 DOI: 10.1038/oncsis.2017.42] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2017] [Revised: 03/23/2017] [Accepted: 04/20/2017] [Indexed: 12/27/2022] Open
Abstract
Breast tumours progress from hyperplasia to ductal carcinoma in situ (DCIS) and invasive breast carcinoma (IBC). PRH/HHEX (proline-rich homeodomain/haematopoietically expressed homeobox) is a transcription factor that displays both tumour suppressor and oncogenic activity in different disease contexts; however, the role of PRH in breast cancer is poorly understood. Here we show that nuclear localization of the PRH protein is decreased in DCIS and IBC compared with normal breast. Our previous work has shown that PRH phosphorylation by protein kinase CK2 prevents PRH from binding to DNA and regulating the transcription of multiple genes encoding growth factors and growth factor receptors. Here we show that transcriptionally inactive phosphorylated PRH is elevated in DCIS and IBC compared with normal breast. To determine the consequences of PRH loss of function in breast cancer cells, we generated inducible PRH depletion in MCF-7 cells. We show that PRH depletion results in increased MCF-7 cell proliferation in part at least due to increased vascular endothelial growth factor signalling. Moreover, we demonstrate that PRH depletion increases the formation of breast cancer cells with cancer stem cell-like properties. Finally, and in keeping with these findings, we show that PRH overexpression inhibits the growth of mammary tumours in mice. Collectively, these data indicate that PRH plays a tumour suppressive role in the breast and they provide an explanation for the finding that low PRH mRNA levels are associated with a poor prognosis in breast cancer.
Collapse
|
14
|
A role for prolyl isomerase PIN1 in the phosphorylation-dependent modulation of PRRXL1 function. Biochem J 2017; 474:683-697. [PMID: 28049756 DOI: 10.1042/bcj20160560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2016] [Revised: 12/10/2016] [Accepted: 01/03/2017] [Indexed: 11/17/2022]
Abstract
Prrxl1 encodes for a paired-like homeodomain transcription factor essential for the correct establishment of the dorsal root ganglion - spinal cord nociceptive circuitry during development. Prrxl1-null mice display gross anatomical disruption of this circuitry, which translates to a markedly diminished sensitivity to noxious stimuli. Here, by the use of an immunoprecipitation and mass spectrometry approach, we identify five highly conserved phosphorylation sites (T110, S119, S231, S233 and S251) in PRRXL1 primary structure. Four are phospho-S/T-P sites, which suggest a role for the prolyl isomerase PIN1 in regulating PRRXL1. Accordingly, PRRXL1 physically interacts with PIN1 and displays diminished transcriptional activity in a Pin1-null cell line. Additionally, these S/T-P sites seem to be important for PRRXL1 conformation, and their point mutation to alanine or aspartate down-regulates PRRXL1 transcriptional activity. Altogether, our findings provide evidence for a putative novel role of PIN1 in the development of the nociceptive system and indicate phosphorylation-mediated conformational changes as a mechanism for regulating the PRRXL1 role in the process.
Collapse
|
15
|
CK2 abrogates the inhibitory effects of PRH/HHEX on prostate cancer cell migration and invasion and acts through PRH to control cell proliferation. Oncogenesis 2017; 6:e293. [PMID: 28134934 PMCID: PMC5294245 DOI: 10.1038/oncsis.2016.82] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 12/16/2015] [Accepted: 01/26/2016] [Indexed: 01/02/2023] Open
Abstract
PRH/HHEX (proline-rich homeodomain protein/haematopoietically expressed homeobox protein) is a transcription factor that controls cell proliferation, cell differentiation and cell migration. Our previous work has shown that in haematopoietic cells, Protein Kinase CK2-dependent phosphorylation of PRH results in the inhibition of PRH DNA-binding activity, increased cleavage of PRH by the proteasome and the misregulation of PRH target genes. Here we show that PRH and hyper-phosphorylated PRH are present in normal prostate epithelial cells, and that hyper-phosphorylated PRH levels are elevated in benign prostatic hyperplasia, prostatic adenocarcinoma, and prostate cancer cell lines. A reduction in PRH protein levels increases the motility of normal prostate epithelial cells and conversely, PRH over-expression inhibits prostate cancer cell migration and blocks the ability of these cells to invade an extracellular matrix. We show that CK2 over-expression blocks the repression of prostate cancer cell migration and invasion by PRH. In addition, we show that PRH knockdown in normal immortalised prostate cells results in an increase in the population of cells capable of colony formation in Matrigel, as well as increased cell invasion and decreased E-cadherin expression. Inhibition of CK2 reduces PRH phosphorylation and reduces prostate cell proliferation but the effects of CK2 inhibition on cell proliferation are abrogated in PRH knockdown cells. These data suggest that the increased phosphorylation of PRH in prostate cancer cells increases both cell proliferation and tumour cell migration/invasion.
Collapse
|
16
|
Gaston K, Tsitsilianos MA, Wadey K, Jayaraman PS. Misregulation of the proline rich homeodomain (PRH/HHEX) protein in cancer cells and its consequences for tumour growth and invasion. Cell Biosci 2016; 6:12. [PMID: 26877867 PMCID: PMC4752775 DOI: 10.1186/s13578-016-0077-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 02/01/2016] [Indexed: 02/07/2023] Open
Abstract
The proline rich homeodomain protein (PRH), also known as haematopoietically expressed homeobox (HHEX), is an essential transcription factor in embryonic development and in the adult. The PRH protein forms oligomeric complexes that bind to tandemly repeated PRH recognition sequences within or at a distance from PRH-target genes and recruit a variety of PRH-interacting proteins. PRH can also bind to other transcription factors and co-regulate specific target genes either directly through DNA binding, or indirectly through effects on the activity of its partner proteins. In addition, like some other homeodomain proteins, PRH can regulate the translation of specific mRNAs. Altered PRH expression and altered PRH intracellular localisation, are associated with breast cancer, liver cancer and thyroid cancer and some subtypes of leukaemia. This is consistent with the involvement of multiple PRH-interacting proteins, including the oncoprotein c-Myc, translation initiation factor 4E (eIF4E), and the promyelocytic leukaemia protein (PML), in the control of cell proliferation and cell survival. Similarly, multiple PRH target genes, including the genes encoding vascular endothelial growth factor (VEGF), VEGF receptors, Endoglin, and Goosecoid, are known to be important in the control of cell proliferation and cell survival and/or the regulation of cell migration and invasion. In this review, we summarise the evidence that implicates PRH in tumourigenesis and we review the data that suggests PRH levels could be useful in cancer prognosis and in the choice of treatment options.
Collapse
Affiliation(s)
- Kevin Gaston
- School of Biochemistry, University Walk, University of Bristol, Bristol, BS8 1TD UK
| | | | - Kerry Wadey
- School of Biochemistry, University Walk, University of Bristol, Bristol, BS8 1TD UK
| | - Padma-Sheela Jayaraman
- Division of Immunity and Infection, School of Medicine, University of Birmingham, Edgbaston, Birmingham, B15 2TT UK
| |
Collapse
|
17
|
Kershaw RM, Siddiqui YH, Roberts D, Jayaraman PS, Gaston K. PRH/HHex inhibits the migration of breast and prostate epithelial cells through direct transcriptional regulation of Endoglin. Oncogene 2013; 33:5592-600. [PMID: 24240683 DOI: 10.1038/onc.2013.496] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 09/19/2013] [Accepted: 10/11/2013] [Indexed: 12/16/2022]
Abstract
PRH/HHex (proline-rich homeodomain protein) is a transcription factor that controls cell proliferation and cell differentiation in a variety of tissues. Aberrant subcellular localisation of PRH is associated with breast cancer and thyroid cancer. Further, in blast crisis chronic myeloid leukaemia, and a subset of acute myeloid leukaemias, PRH is aberrantly localised and its activity is downregulated. Here we show that PRH is involved in the regulation of cell migration and cancer cell invasion. We show for the first time that PRH is expressed in prostate cells and that a decrease in PRH protein levels increases the migration of normal prostate epithelial cells. We show that a decrease in PRH protein levels also increases the migration of normal breast epithelial cells. Conversely, PRH overexpression inhibits cell migration and cell invasion by PC3 and DU145 prostate cancer cells and MDA-MB-231 breast cancer cells. Previous work has shown that the transforming growth factor-β co-receptor Endoglin inhibits the migration of prostate and breast cancer cells. Here we show that PRH can bind to the Endoglin promoter in immortalised prostate and breast cells. PRH overexpression in these cells results in increased Endoglin protein expression, whereas PRH knockdown results in decreased Endoglin protein expression. Moreover, we demonstrate that Endoglin overexpression abrogates the increased migration shown by PRH knockdown cells. Our data suggest that PRH controls the migration of multiple epithelial cell lineages in part at least through the direct transcriptional regulation of Endoglin. We discuss these results in terms of the functions of PRH in normal cells and the mislocalisation of PRH seen in multiple cancer cell types.
Collapse
Affiliation(s)
- R M Kershaw
- Division of Immunity and Infection, School of Medicine, University of Birmingham, Edgbaston, Birmingham, UK
| | - Y H Siddiqui
- School of Biochemistry, University Walk, University of Bristol, Bristol, UK
| | - D Roberts
- Division of Immunity and Infection, School of Medicine, University of Birmingham, Edgbaston, Birmingham, UK
| | - P-S Jayaraman
- Division of Immunity and Infection, School of Medicine, University of Birmingham, Edgbaston, Birmingham, UK
| | - K Gaston
- School of Biochemistry, University Walk, University of Bristol, Bristol, UK
| |
Collapse
|
18
|
Jeličić B, Nemet J, Traven A, Sopta M. Solvent-exposed serines in the Gal4 DNA-binding domain are required for promoter occupancy and transcriptional activation in vivo. FEMS Yeast Res 2013; 14:302-9. [PMID: 24119159 DOI: 10.1111/1567-1364.12106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 08/27/2013] [Accepted: 09/27/2013] [Indexed: 11/30/2022] Open
Abstract
The yeast transcriptional activator Gal4 has long been the prototype for studies of eukaryotic transcription. Gal4 is phosphorylated in the DNA-binding domain (DBD); however, the molecular details and functional significance of this remain unknown. We mutagenized seven potential phosphoserines that lie on the solvent-exposed face of the DBD structure and assessed them for transcriptional activity and DNA binding in vivo. Serine to alanine mutants at positions 22, 47, and 85 show the greatest reduction in promoter occupancy and transcriptional activity at the MEL1 promoter containing a single UASGAL . Substitutions with the phosphomimetic aspartate restored DNA-binding and transcriptional activity at serines 22 and 85, suggesting that they are potential sites of Gal4 phosphorylation in vivo. In contrast, the serine to alanine mutants, except serine 22, were fully proficient for binding to the GAL1-10 promoter, containing multiple UASGAL sites, although they had a reduced ability to activate transcription. Collectively, these data show that at the GAL1-10 promoter, functions of the DBD in transcriptional activation can be uncoupled from roles in promoter binding. We suggest that the serines in the DBD mediate protein-protein contacts with the transcription machinery, leading to stabilization of Gal4 at promoters.
Collapse
Affiliation(s)
- Branka Jeličić
- Department of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | | | | | | |
Collapse
|
19
|
CK2 phosphorylation inactivates DNA binding by the papillomavirus E1 and E2 proteins. J Virol 2013; 87:7668-79. [PMID: 23637413 DOI: 10.1128/jvi.00345-13] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Papillomaviruses have complex life cycles that are understood only superficially. Although it is well established that the viral E1 and E2 proteins play key roles in controlling viral transcription and DNA replication, how these factors are regulated is not well understood. Here, we demonstrate that phosphorylation by the protein kinase CK2 controls the biochemical activities of the bovine papillomavirus E1 and E2 proteins by modifying their DNA binding activity. Phosphorylation at multiple sites in the N-terminal domain in E1 results in the loss of sequence-specific DNA binding activity, a feature that is also conserved in human papillomavirus (HPV) E1 proteins. The bovine papillomavirus (BPV) E2 protein, when phosphorylated by CK2 on two specific sites in the hinge, also loses its site-specific DNA binding activity. Mutation of these sites in E2 results in greatly increased levels of latent viral DNA replication, indicating that CK2 phosphorylation of E2 is a negative regulator of viral DNA replication during latent viral replication. In contrast, mutation of the N-terminal phosphorylation sites in E1 has no effect on latent viral DNA replication. We propose that the phosphorylation of the N terminus of E1 plays a role only in vegetative viral DNA replication, and consistent with such a role, caspase 3 cleavage of E1, which has been shown to be necessary for vegetative viral DNA replication, restores the DNA binding activity to phosphorylated E1.
Collapse
|
20
|
Noy P, Gaston K, Jayaraman PS. Dasatinib inhibits leukaemic cell survival by decreasing PRH/Hhex phosphorylation resulting in increased repression of VEGF signalling genes. Leuk Res 2012; 36:1434-7. [PMID: 22874537 PMCID: PMC3462996 DOI: 10.1016/j.leukres.2012.07.013] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2012] [Revised: 06/20/2012] [Accepted: 07/16/2012] [Indexed: 10/29/2022]
Abstract
The PRH/Hhex transcription factor represses multiple genes in the VEGF signalling pathway (VSP) to inhibit myeloid cell survival. Protein kinase CK2 phosphorylates PRH and counteracts the inhibitory effect of this protein on cell survival by blocking the repression of VSP genes. Here we show that the BCR-ABL/Src kinase inhibitor dasatinib decreases PRH phosphorylation and increases PRH-dependent repression of Vegf and Vegfr-1. Moreover in the absence of PRH, dasatinib does not inhibit cell survival as effectively as in PRH expressing cells. Thus the re-establishment of gene control by PRH is in part responsible for the therapeutic effects of dasatinib.
Collapse
Affiliation(s)
- Peter Noy
- School Immunity and Infection, University of Birmingham, Birmingham, UK
| | | | | |
Collapse
|
21
|
Noy P, Sawasdichai A, Jayaraman PS, Gaston K. Protein kinase CK2 inactivates PRH/Hhex using multiple mechanisms to de-repress VEGF-signalling genes and promote cell survival. Nucleic Acids Res 2012; 40:9008-20. [PMID: 22844093 PMCID: PMC3467080 DOI: 10.1093/nar/gks687] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Protein kinase CK2 promotes cell survival and the activity of this kinase is elevated in several cancers including chronic myeloid leukaemia. We have shown previously that phosphorylation of the Proline-Rich Homeodomain protein (PRH/Hhex) by CK2 inhibits the DNA-binding activity of this transcription factor. Furthermore, PRH represses the transcription of multiple genes encoding components of the VEGF-signalling pathway and thereby influences cell survival. Here we show that the inhibitory effects of PRH on cell proliferation are abrogated by CK2 and that CK2 inhibits the binding of PRH at the Vegfr-1 promoter. Phosphorylation of PRH by CK2 also decreases the nuclear association of PRH and induces its cleavage by the proteasome. Moreover, cleavage of phosphorylated PRH produces a stable truncated cleavage product which we have termed PRHΔC (HhexΔC). PRHΔC acts as a transdominant negative regulator of full-length PRH by sequestering TLE proteins that function as PRH co-repressors. We show that this novel regulatory mechanism results in the alleviation of PRH-mediated repression of Vegfr-1. We suggest that the re-establishment of PRH function through inhibition of CK2 could be of value in treatment of myeloid leukaemias, as well as other tumour types in which PRH is inactivated by phosphorylation.
Collapse
Affiliation(s)
- Peter Noy
- Division of Immunity and Infection, School of Medicine, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | | | | | | |
Collapse
|
22
|
The proline rich homeodomain protein PRH/Hhex forms stable oligomers that are highly resistant to denaturation. PLoS One 2012; 7:e35984. [PMID: 22540015 PMCID: PMC3335068 DOI: 10.1371/journal.pone.0035984] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Accepted: 03/29/2012] [Indexed: 11/19/2022] Open
Abstract
Background Many transcription factors control gene expression by binding to specific DNA sequences at or near the genes that they regulate. However, some transcription factors play more global roles in the control of gene expression by altering the architecture of sections of chromatin or even the whole genome. The ability to form oligomeric protein assemblies allows many of these proteins to manipulate extensive segments of DNA or chromatin via the formation of structures such as DNA loops or protein-DNA fibres. Principal Findings Here we show that the proline rich homeodomain protein PRH/Hhex forms predominantly octameric and/or hexadecameric species in solution as well as larger assemblies. We show that these assemblies are highly stable resisting denaturation by temperature and chemical denaturants. Conclusion These data indicate that PRH is functionally and structurally related to the Lrp/AsnC family of proteins, a group of proteins that are known to act globally to control gene expression in bacteria and archaea.
Collapse
|
23
|
Ström CE, Mortusewicz O, Finch D, Parsons JL, Lagerqvist A, Johansson F, Schultz N, Erixon K, Dianov GL, Helleday T. CK2 phosphorylation of XRCC1 facilitates dissociation from DNA and single-strand break formation during base excision repair. DNA Repair (Amst) 2011; 10:961-9. [PMID: 21840775 DOI: 10.1016/j.dnarep.2011.07.004] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2011] [Revised: 07/05/2011] [Accepted: 07/14/2011] [Indexed: 10/17/2022]
Abstract
CK2 phosphorylates the scaffold protein XRCC1, which is required for efficient DNA single-strand break (SSB) repair. Here, we express an XRCC1 protein (XRCC1(ckm)) that cannot be phosphorylated by CK2 in XRCC1 mutated EM9 cells and show that the role of this post-translational modification gives distinct phenotypes in SSB repair and base excision repair (BER). Interestingly, we find that fewer SSBs are formed during BER after treatment with the alkylating agent dimethyl sulfate (DMS) in EM9 cells expressing XRCC1(ckm) (CKM cells) or following inhibition with the CK2 inhibitor 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole (DMAT). We also show that XRCC1(ckm) protein has a higher affinity for DNA than wild type XRCC1 protein and resides in an immobile fraction on DNA, in particular after damage. We propose a model whereby the increased affinity for DNA sequesters XRCC1(ckm) and the repair enzymes associated with it, at the repair site, which retards kinetics of BER. In conclusion, our results indicate that phosphorylation of XRCC1 by CK2 facilitates the BER incision step, likely by promoting dissociation from DNA.
Collapse
Affiliation(s)
- Cecilia E Ström
- Department of Genetics, Microbiology and Toxicology, Stockholm University, S-106 91 Stockholm, Sweden
| | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Morimoto R, Yamamoto A, Akimoto Y, Obinata A. Homeoprotein Hex is expressed in mouse developing chondrocytes. J Biochem 2011; 150:61-71. [PMID: 21454303 DOI: 10.1093/jb/mvr039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Endochondral ossification is a complex process involving the formation of cartilage and the subsequent replacement by mineralized bone. Although the proliferation and differentiation of chondrocytes are strictly regulated, the molecular mechanisms involved are not completely understood. Here, we show that a divergent-type homeobox gene, hematopoietically expressed homeobox gene (HEX), is expressed in mouse chondrogenic cell line ATDC5. The expression of Hex protein drastically increased during differentiation. The chondrogenic differentiation-enhanced expression of Hex protein was also observed in chondrocytes in the tibia of embryonic day 15.5 (E15.5) mouse embryos. The localization of Hex protein in the chondrocytes of the tibia changed in association with maturation; namely, there was Hex protein in the cytoplasm near the endoplasmic reticulum (ER) in resting chondrocytes, which moved to the nucleus in prehypertrophic chondrocytes, and thereafter entered the ER in hypertrophic chondrocytes. These results suggest Hex expression and subcellular localization are associated with chondrocyte maturation.
Collapse
Affiliation(s)
- Riyo Morimoto
- Department of Physiological Chemistry II, Faculty of Pharmaceutical Science, Teikyo University, Kanagawa, Japan.
| | | | | | | |
Collapse
|
25
|
Ye W, Lin W, Tartakoff AM, Tao T. Karyopherins in nuclear transport of homeodomain proteins during development. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2011; 1813:1654-62. [PMID: 21256166 DOI: 10.1016/j.bbamcr.2011.01.013] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 12/08/2010] [Accepted: 01/09/2011] [Indexed: 01/12/2023]
Abstract
Homeodomain proteins are crucial transcription factors for cell differentiation, cell proliferation and organ development. Interestingly, their homeodomain signature structure is important for both their DNA-binding and their nucleocytoplasmic trafficking. The accurate nucleocytoplasmic distribution of these proteins is essential for their functions. We summarize information on (a) the roles of karyopherins for import and export of homeoproteins, (b) the regulation of their nuclear transport during development, and (c) the corresponding complexity of homeoprotein nucleocytoplasmic transport signals. This article is part of a Special Issue entitled: Regulation of Signaling and Cellular Fate through Modulation of Nuclear Protein Import.
Collapse
Affiliation(s)
- Wenduo Ye
- Xiamen University School of Life Sciences, Xiamen, Fujian 361005, China
| | | | | | | |
Collapse
|
26
|
Zhang L, Fujita T, Wu G, Xiao X, Wan Y. Phosphorylation of the anaphase-promoting complex/Cdc27 is involved in TGF-beta signaling. J Biol Chem 2011; 286:10041-50. [PMID: 21209074 DOI: 10.1074/jbc.m110.205518] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Loss of TGF-β-induced growth inhibition is a hallmark of many human tumors. Previous studies implied that activation of the anaphase-promoting complex (APC/cyclosome) is involved in the TGF-β signaling pathway, which facilitates the destruction of SnoN, a transcriptional co-suppressor, which leads in turn to the transactivation of TGF-β-responsive genes for cell cycle arrest. The function of APC was demonstrated in TGF-β signal transduction, but the mechanism by which it is activated in response to TGF-β signaling remains unclear. We report here that phosphorylation of Cdc27, a core subunit of APC, in response to TGF-β signaling can facilitate the activation of APC. We have demonstrated that casein kinase II (CKII) is involved in the phosphorylation of Cdc27 in response to TGF-β signaling. Depletion of CKII by shRNA abolishes the TGF-β-induced phosphorylation of Cdc27 and subsequent degradation of SnoN. Disruptive mutation of Cdc27 (S154A) attenuates TGF-β-induced SnoN degradation. In addition, expression of a phosphorylation-resistant Cdc27 mutant significantly attenuates TGF-β-induced growth inhibition. Together, the results suggest that phosphorylation of Cdc27 by CKII is involved in TGF-β-induced activation of APC.
Collapse
Affiliation(s)
- Liyong Zhang
- Department of Cell Biology and Physiology, University of Pittsburgh School of Medicine and University of Pittsburgh Cancer Institute, Pittsburgh, Pennsylvania 15213, USA
| | | | | | | | | |
Collapse
|
27
|
Protein kinase CK2α subunit over-expression correlates with metastatic risk in breast carcinomas: quantitative immunohistochemistry in tissue microarrays. Eur J Cancer 2010; 47:792-801. [PMID: 21194925 DOI: 10.1016/j.ejca.2010.11.028] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2010] [Revised: 11/19/2010] [Accepted: 11/26/2010] [Indexed: 01/03/2023]
Abstract
BACKGROUND CK2α is a signalling molecule that participates in major events in solid tumour progression. The aim of this study was to evaluate the prognostic significance of the immunohistochemical expression of CK2α in breast carcinomas. METHODS Quantitative measurements of immunohistochemical expression of 33 biomarkers using high-throughput densitometry, assessed on digitised microscopic tissue micro-array images were correlated with clinical outcome in 1000 breast carcinomas using univariate and multivariate analyses. RESULTS In univariate analysis, CK2α was a significant prognostic indicator (p<0.001). Moreover, a multivariable model allowed the selection of the best combination of the 33 biomarkers to predict patients' outcome through logistic regression. A nine-marker signature highly predictive of metastatic risk, associating SHARP-2, STAT1, eIF4E, pmapKAPk-2, pAKT, caveolin, VEGF, FGF-1 and CK2α permitted to classify well 82.32% of patients (specificity 81.59%, sensitivity 92.55%, area under ROC curve 0.939). Importantly, in a node negative subset of patients an even more (86%) clinically relevant association of eleven markers was found predictive of poor outcome. CONCLUSION A strong quantitative CK2α immunohistochemical expression in breast carcinomas is individually a significant indicator of poor prognosis. Moreover, an immunohistochemical signature of 11 markers including CK2α accurately (86%) well classifies node negative patients in good and poor outcome subsets. Our results suggest that CK2α evaluation together with key downstream CK2 targets might be a useful tool to identify patients at high risk of distant metastases and that CK2 can be considered as a relevant target for potential specific therapy.
Collapse
|
28
|
Chen E, Huang X, Zheng Y, Li YJ, Chesney A, Ben-David Y, Yang E, Hough MR. Phosphorylation of HOX11/TLX1 on Threonine-247 during mitosis modulates expression of cyclin B1. Mol Cancer 2010; 9:246. [PMID: 20846384 PMCID: PMC2949800 DOI: 10.1186/1476-4598-9-246] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Accepted: 09/16/2010] [Indexed: 12/20/2022] Open
Abstract
BACKGROUND The HOX11/TLX1 (hereafter referred to as HOX11) homeobox gene was originally identified at a t(10;14)(q24;q11) translocation breakpoint, a chromosomal abnormality observed in 5-7% of T cell acute lymphoblastic leukemias (T-ALLs). We previously reported a predisposition to aberrant spindle assembly checkpoint arrest and heightened incidences of chromosome missegregation in HOX11-overexpressing B lymphocytes following exposure to spindle poisons. The purpose of the current study was to evaluate cell cycle specific expression of HOX11. RESULTS Cell cycle specific expression studies revealed a phosphorylated form of HOX11 detectable only in the mitotic fraction of cells after treatment with inhibitors to arrest cells at different stages of the cell cycle. Mutational analyses revealed phosphorylation on threonine-247 (Thr247), a conserved amino acid that defines the HOX11 gene family and is integral for the association with DNA binding elements. The effect of HOX11 phosphorylation on its ability to modulate expression of the downstream target, cyclin B1, was tested. A HOX11 mutant in which Thr247 was substituted with glutamic acid (HOX11 T247E), thereby mimicking a constitutively phosphorylated HOX11 isoform, was unable to bind the cyclin B1 promoter or enhance levels of the cyclin B1 protein. Expression of the wildtype HOX11 was associated with accelerated progression through the G2/M phase of the cell cycle, impaired synchronization in prometaphase and reduced apoptosis whereas expression of the HOX11 T247E mutant restored cell cycle kinetics, the spindle checkpoint and apoptosis. CONCLUSIONS Our results demonstrate that the transcriptional activity of HOX11 is regulated by phosphorylation of Thr247 in a cell cycle-specific manner and that this phosphorylation modulates the expression of the target gene, cyclin B1. Since it is likely that Thr247 phosphorylation regulates DNA binding activity to multiple HOX11 target sequences, it is conceivable that phosphorylation functions to regulate the expression of HOX11 target genes involved in the control of the mitotic spindle checkpoint.
Collapse
Affiliation(s)
- Edwin Chen
- Institute of Medical Science, University of Toronto, Toronto, Ontario M5S1A8, Canada
| | | | | | | | | | | | | | | |
Collapse
|
29
|
Soufi A, Sawasdichai A, Shukla A, Noy P, Dafforn T, Smith C, Jayaraman PS, Gaston K. DNA compaction by the higher-order assembly of PRH/Hex homeodomain protein oligomers. Nucleic Acids Res 2010; 38:7513-25. [PMID: 20675722 PMCID: PMC2995075 DOI: 10.1093/nar/gkq659] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Protein self-organization is essential for the establishment and maintenance of nuclear architecture and for the regulation of gene expression. We have shown previously that the Proline-Rich Homeodomain protein (PRH/Hex) self-assembles to form oligomeric complexes that bind to arrays of PRH binding sites with high affinity and specificity. We have also shown that many PRH target genes contain suitably spaced arrays of PRH sites that allow this protein to bind and regulate transcription. Here, we use analytical ultracentrifugation and electron microscopy to further characterize PRH oligomers. We use the same techniques to show that PRH oligomers bound to long DNA fragments self-associate to form highly ordered assemblies. Electron microscopy and linear dichroism reveal that PRH oligomers can form protein-DNA fibres and that PRH is able to compact DNA in the absence of other proteins. Finally, we show that DNA compaction is not sufficient for the repression of PRH target genes in cells. We conclude that DNA compaction is a consequence of the binding of large PRH oligomers to arrays of binding sites and that PRH is functionally and structurally related to the Lrp/AsnC family of proteins from bacteria and archaea, a group of proteins formerly thought to be without eukaryotic equivalents.
Collapse
Affiliation(s)
- Abdenour Soufi
- Institute for Biomedical Research, Birmingham University Medical School, Edgbaston, Birmingham B15 2TT, UK
| | | | | | | | | | | | | | | |
Collapse
|
30
|
Guo S, Vanderford NL, Stein R. Phosphorylation within the MafA N terminus regulates C-terminal dimerization and DNA binding. J Biol Chem 2010; 285:12655-61. [PMID: 20208071 DOI: 10.1074/jbc.m110.105759] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Phosphorylation regulates transcription factor activity by influencing dimerization, cellular localization, activation potential, and/or DNA binding. Nevertheless, precisely how this post-translation modification mediates these processes is poorly understood. Here, we examined the role of phosphorylation on the DNA-binding properties of MafA and MafB, closely related transcriptional activators of the basic-leucine zipper (b-Zip) family associated with cell differentiation and oncogenesis. Many common phosphorylation sites were identified by mass spectrometry. However, dephosphorylation only precluded the detection of MafA dimers and consequently dramatically reduced DNA-binding ability. Analysis of MafA/B chimeras revealed that sensitivity to the phosphorylation status of MafA was imparted by sequences spanning the C-terminal dimerization region (amino acids (aa) 279-359), whereas the homologous MafB region (aa 257-323) conveyed phosphorylation-independent DNA binding. Mutational analysis showed that formation of MafA dimers capable of DNA binding required phosphorylation within the distinct N-terminal transactivation domain (aa 1-72) and not the C-terminal b-Zip region. These results demonstrate a novel relationship between the phosphoamino acid-rich transactivation and b-Zip domains in controlling MafA DNA-binding activity.
Collapse
Affiliation(s)
- Shuangli Guo
- From the Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, Tennessee 37232
| | | | | |
Collapse
|
31
|
PRH/Hhex controls cell survival through coordinate transcriptional regulation of vascular endothelial growth factor signaling. Mol Cell Biol 2010; 30:2120-34. [PMID: 20176809 DOI: 10.1128/mcb.01511-09] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The proline-rich homeodomain protein (PRH) plays multiple roles in the control of gene expression during embryonic development and in the adult. Vascular endothelial growth factor (VEGF) is a mitogen that stimulates cell proliferation and survival via cell surface receptors including VEGFR-1 and VEGFR-2. VEGF signaling is of critical importance in angiogenesis and hematopoiesis and is elevated in many tumors. Here we show that PRH binds directly to the promoter regions of the Vegf, Vegfr-1, and Vegfr-2 genes and that in each case PRH represses transcription. We demonstrate that overexpression or knockdown of PRH directly impinges on the survival of both leukemic and tumor cells and that the modulation of VEGF and VEGF receptor signaling by PRH mediates these effects. Our findings demonstrate that PRH is a key regulator of the VEGF signaling pathway and describe a mechanism whereby PRH plays an important role in tumorigenesis and leukemogenesis.
Collapse
|
32
|
Marfil V, Moya M, Pierreux CE, Castell JV, Lemaigre FP, Real FX, Bort R. Interaction between Hhex and SOX13 modulates Wnt/TCF activity. J Biol Chem 2009; 285:5726-37. [PMID: 20028982 DOI: 10.1074/jbc.m109.046649] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Fine-tuning of the Wnt/TCF pathway is crucial for multiple embryological processes, including liver development. Here we describe how the interaction between Hhex (hematopoietically expressed homeobox) and SOX13 (SRY-related high mobility group box transcription factor 13), modulates Wnt/TCF pathway activity. Hhex is a homeodomain factor expressed in multiple endoderm-derived tissues, like the liver, where it is essential for proper development. The pleiotropic expression of Hhex during embryonic development and its dual role as a transcriptional repressor and activator suggest the presence of different tissue-specific partners capable of modulating its activity and function. While searching for developmentally regulated Hhex partners, we set up a yeast two-hybrid screening using an E9.5-10.5 mouse embryo library and the N-terminal domain of Hhex as bait. Among the putative protein interactors, we selected SOX13 for further characterization. We found that SOX13 interacts directly with full-length Hhex, and we delineated the interaction domains within the two proteins. SOX13 is known to repress Wnt/TCF signaling by interacting with TCF1. We show that Hhex is able to block the SOX13-dependent repression of Wnt/TCF activity by displacing SOX13 from the SOX13 x TCF1 complex. Moreover, Hhex de-repressed the Wnt/TCF pathway in the ventral foregut endoderm of cultured mouse embryos electroporated with a SOX13-expressing plasmid. We conclude that the interaction between Hhex and SOX13 may contribute to control Wnt/TCF signaling in the early embryo.
Collapse
Affiliation(s)
- Vanessa Marfil
- Unitat de Biologia Cellular i Molecular, Institut Municipal d'Investigació Mèdica, Universitat Pompeu Fabra, Barcelona 08003, Spain
| | | | | | | | | | | | | |
Collapse
|