1
|
ILRUN Downregulates ACE2 Expression and Blocks Infection of Human Cells by SARS-CoV-2. J Virol 2021; 95:e0032721. [PMID: 33963054 DOI: 10.1128/jvi.00327-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The human protein-coding gene ILRUN (inflammation and lipid regulator with UBA-like and NBR1-like domains; previously C6orf106) was identified as a proviral factor for Hendra virus infection and was recently characterized to function as an inhibitor of type I interferon expression. Here, we have utilized transcriptome sequencing (RNA-seq) to define cellular pathways regulated by ILRUN in the context of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection of Caco-2 cells. We find that inhibition of ILRUN expression by RNA interference alters transcription profiles of numerous cellular pathways, including upregulation of the SARS-CoV-2 entry receptor ACE2 and several other members of the renin-angiotensin aldosterone system. In addition, transcripts of the SARS-CoV-2 coreceptors TMPRSS2 and CTSL were also upregulated. Inhibition of ILRUN also resulted in increased SARS-CoV-2 replication, while overexpression of ILRUN had the opposite effect, identifying ILRUN as a novel antiviral factor for SARS-CoV-2 replication. This represents, to our knowledge, the first report of ILRUN as a regulator of the renin-angiotensin-aldosterone system (RAAS). IMPORTANCE There is no doubt that the current rapid global spread of COVID-19 has had significant and far-reaching impacts on our health and economy and will continue to do so. Research in emerging infectious diseases, such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is growing rapidly, with new breakthroughs in the understanding of host-virus interactions to assist with the development of innovative and exciting therapeutic strategies. Here, we present the first evidence that modulation of the human protein-coding gene ILRUN functions as an antiviral factor for SARS-CoV-2 infection, likely through its newly identified role in regulating the expression of SARS-CoV-2 entry receptors ACE2, TMPRSS2, and CTSL. These data improve our understanding of biological pathways that regulate host factors critical to SARS-CoV-2 infection, contributing to the development of antiviral strategies to deal with the current SARS-CoV-2 pandemic.
Collapse
|
2
|
Ding XY, Gu RP, Tang WY, Shu QM, Xu GZ, Zhang M. Effect of Phosphorylated-Extracellular Regulated Kinase 1/2 Inhibitor on Retina from Light-induced Photoreceptor Degeneration. Chin Med J (Engl) 2018; 131:2836-2843. [PMID: 30511686 PMCID: PMC6278201 DOI: 10.4103/0366-6999.246064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Background The demonstrated role of mitogen-activated protein kinase (MAPK) in both cell apoptosis and the inflammation pathway makes it an attractive target for photoreceptor protection. The aim of this study was to investigate the protective effects of MAPK antagonists against photoreceptor degeneration and retinal inflammation in a rat model of light-induced retinal degeneration. Methods Sprague Dawley rats were treated with intravitreal injections of MAPK antagonists, inhibitors of p-P38, phosphorylated-extracellular regulated kinase (p-ERK) 1/2, and p-c-Jun N-terminal kinase (JNK) just before they were assigned to dark adaptation. After dark adaptation for 24 h, rats were exposed to blue light (2500 lux) in a light box for 24 h, and then returned to the normal 12-h light/12-h dark cycle. Samples were collected at different time points. MAPK expression during light exposure was examined with immunofluorescence. Photoreceptor death was detected with histopathology and terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) staining. The expression of retinal p-ERK1/2, caspase 3, activated caspase 3, tumor necrosis factor (TNF)-α, and interleukin (IL)-1β was examined by Western blotting. Differences between groups were evaluated using unpaired one-way analysis of variance and least significant difference post hoc tests. Results MAPKs (P38, ERK1/2, and p-JNK) were phosphorylated and activated in the light injury groups, compared with normal group, and their expressions were mainly elevated in the outer nuclear layer (ONL). Among the selected MAPK antagonists, only the p-ERK1/2 inhibitor attenuated the loss of photoreceptors and the thinning of ONL in light injury groups. Besides, p-ERK1/2 inhibitor refrained light-induced photoreceptor apoptosis, which was presented by TUNEL positive cells. Light injury significantly increased the expression of p-ERK1/2 (1.12 ± 0.06 vs. 0.57 ± 0.08, t = 9.99, P < 0.05; 1.23 ± 0.03 vs. 0.57 ± 0.08, t = 11.90, P < 0.05; and 1.12 ± 0.12 vs. 0.57 ± 0.08, t = 9.86, P < 0.05; F = 49.55, P < 0.001), and induced caspase 3 activating (0.63 ± 0.06 vs. 0.14 ± 0.05, t = 13.67, P < 0.05; 0.74 ± 0.05 vs. 0.14 ± 0.05, t = 16.87, P < 0.05; and 0.80 ± 0.05 vs. 0.14 ± 0.05, t = 18.57, P < 0.05; F = 100.15, P < 0.001), compared with normal group. The p-ERK1/2 inhibitor significantly reduced p-ERK1/2 overexpression (0.61 ± 0.06 vs. 1.12 ± 0.06, t = -9.26, P < 0.05; 0.77 ± 0.06 vs. 1.23 ± 0.03, t = -8.29, P < 0.05; and 0.68 ± 0.03 vs. 1.12 ± 0.12, t = -7.83, P < 0.05; F = 49.55, P < 0.001) and downregulated caspase 3 activating (0.23 ± 0.04 vs. 0.63 ± 0.06, t = -11.24, P < 0.05; 0.43 ± 0.03 vs. 0.74 ± 0.05, t = -8.86, P < 0.05; and 0.58 ± 0.03 vs. 0.80 ± 0.05, t = -6.17, P < 0.05; F = 100.15, P < 0.001), compared with light injury group. No significant change in the total level of caspase 3 was seen in different groups (F = 0.56, P = 0.75). As for inflammation, light injury significantly increased the expression of TNF-α (0.42 ± 0.04 vs. 0.25 ± 0.05, t = 5.99, P < 0.05; 0.65 ± 0.03 vs. 0.25 ± 0.05, t = 14.87, P < 0.05; and 0.86 ± 0.04 vs. 0.25 ± 0.05, t = 22.58, P < 0.05; F = 160.27, P < 0.001) and IL-1β (0.24 ± 0.01 vs. 0.19 ± 0.02, t = 2.33, P < 0.05; 0.35 ± 0.02 vs. 0.19 ± 0.02, t = 7.97, P < 0.05; and 0.48 ± 0.04 vs. 0.19 ± 0.02, t = 14.69, P < 0.05; F = 77.29, P < 0.001), compared with normal group. P-ERK1/2 inhibitor significantly decreased the overexpression of TNF-α (0.22 ± 0.02 vs. 0.42 ± 0.04, t = -7.40, P < 0.05; 0.27 ± 0.02 vs. 0.65 ± 0.03, t = -14.27, P < 0.05; and 0.33 ± 0.03 vs. 0.86 ± 0.04, t = -19.58, P < 0.05; F = 160.27, P < 0.001) and IL-1β (0.13 ± 0.03 vs. 0.24 ± 0.01, t = -5.77, P < 0.05; 0.17 ± 0.01 vs. 0.22 ± 0.02, t = -9.18, P < 0.05; and 0.76 ± 0.05 vs. 0.48 ± 0.04, t = -13.12, P < 0.05; F = 77.29, P < 0.001), compared with light injury group. Conclusion The p-ERK1/2 inhibitor might protect the retina from light-induced photoreceptor degeneration and retinal inflammation.
Collapse
Affiliation(s)
- Xin-Yi Ding
- Department of Ophthalmology; Institute of Eye Research, Eye and ENT Hospital of Fudan University; Key Laboratory of Myopia of State Health Ministry (Fudan University); Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China
| | - Rui-Ping Gu
- Department of Ophthalmology; Institute of Eye Research, Eye and ENT Hospital of Fudan University; Key Laboratory of Myopia of State Health Ministry (Fudan University); Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China
| | - Wen-Yi Tang
- Department of Ophthalmology; Institute of Eye Research, Eye and ENT Hospital of Fudan University; Key Laboratory of Myopia of State Health Ministry (Fudan University); Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China
| | - Qin-Meng Shu
- Department of Ophthalmology; Institute of Eye Research, Eye and ENT Hospital of Fudan University; Key Laboratory of Myopia of State Health Ministry (Fudan University); Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China
| | - Ge-Zhi Xu
- Department of Ophthalmology; Institute of Eye Research, Eye and ENT Hospital of Fudan University; Key Laboratory of Myopia of State Health Ministry (Fudan University); Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China
| | - Meng Zhang
- Department of Ophthalmology; Institute of Eye Research, Eye and ENT Hospital of Fudan University; Key Laboratory of Myopia of State Health Ministry (Fudan University); Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai 200031, China
| |
Collapse
|
3
|
Srivastava R, Mannam P, Rauniyar N, Lam TT, Luo R, Lee PJ, Srivastava A. Proteomics data on MAP Kinase Kinase 3 knock out bone marrow derived macrophages exposed to cigarette smoke extract. Data Brief 2017; 13:320-325. [PMID: 28653025 PMCID: PMC5476452 DOI: 10.1016/j.dib.2017.05.049] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2016] [Revised: 05/22/2017] [Accepted: 05/23/2017] [Indexed: 11/26/2022] Open
Abstract
This data article reports changes in the phosphoproteome and total proteome of cigarette smoke extract (CSE) exposed WT and MAP Kinase Kinase 3 knock out (MKK3−/−) bone marrow derived macrophages (BMDM). The dataset generated is helpful for understanding the mechanism of CSE induced inflammation and the role of MAP kinase signaling pathway. The cellular proteins were labeled with isobaric tags for relative and absolute quantitation (iTRAQ®) reagents and analyzed by LC-MS/MS. The standard workflow module for iTRAQ® quantification within the Proteome Discoverer was utilized for the data analysis. Ingenuity Pathway Analysis (IPA) software and Reactome was used to identify enriched canonical pathways and molecular networks (Mannam et al., 2016) [1]. All the associated mass spectrometry data has been deposited in the Yale Protein Expression Database (YPED) with the web-link to the data: http://yped.med.yale.edu/repository/ViewSeriesMenu.do;jsessionid=6A5CB07543D8B529FAE8C3FCFE29471D?series_id=5044&series_name=MMK3+Deletion+in+MEFs
Collapse
Affiliation(s)
- Roshni Srivastava
- Department of Internal Medicine, Yale University School of Medicine, USA
| | - Praveen Mannam
- Department of Internal Medicine, Yale University School of Medicine, USA
| | - Navin Rauniyar
- MS & Proteomics Resource at Yale University, WM Keck Foundation Biotechnology Resource Laboratory, Department of Molecular Biophysics and Biochemistry, New Haven, CT, USA
| | - TuKiet T Lam
- MS & Proteomics Resource at Yale University, WM Keck Foundation Biotechnology Resource Laboratory, Department of Molecular Biophysics and Biochemistry, New Haven, CT, USA
| | - Ruiyan Luo
- Department of Epidemiology & Biostatistics, School of Public Health, Georgia State University, Atlanta, GA, USA
| | - Patty J Lee
- Department of Internal Medicine, Yale University School of Medicine, USA
| | - Anup Srivastava
- Division of Translational and Regenerative Medicine, Internal Medicine, University of Arizona, Tucson, AZ, USA
| |
Collapse
|
4
|
Srivastava A, Shinn AS, Lam TT, Lee PJ, Mannam P. SILAC based protein profiling data of MKK3 knockout mouse embryonic fibroblasts. Data Brief 2016; 7:418-22. [PMID: 26977448 PMCID: PMC4782019 DOI: 10.1016/j.dib.2016.02.034] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 02/12/2016] [Accepted: 02/12/2016] [Indexed: 11/28/2022] Open
Abstract
This data article reports changes in the phospho and total proteome of MKK3 knock out (MKK3−/−) mouse embryonic fibroblasts (MEFs). The dataset generated highlights the changes at protein level which can be helpful for understanding targets of the MAP kinase signaling pathway. Data was collected after TiO2-based phosphopeptide enrichment of whole cell lysate at baseline condition with bottom-up SILAC-based LC MS/MS quantitative mass spectrometry. We report all the proteins and peptides identified and quantified in MKK3−/− and WT MEFs. The altered pathways in MKK3−/− MEFs were analyzed by Database for Annotation, Visualization and Integrated Discovery (DAVID, v6.7) and Ingenuity Pathway Analysis (IPA) and are presented as a table and graph, respectively. The data reported here is related to the published work [1]. All the associated mass spectrometry data has been deposited in the Yale Protein Expression Database (YPED) with the web-link to the data: http://yped.med.yale.edu/repository/ViewSeriesMenu.do;jsessionid=6A5CB07543D8B529FAE8C3FCFE29471D?series_id=5044&series_name=MMK3+Deletion+in+MEFs.
Collapse
Affiliation(s)
- Anup Srivastava
- Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520-8057, USA
| | - Amanda S Shinn
- Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520-8057, USA
| | - TuKiet T Lam
- MS & Proteomics Resource at Yale University, WM Keck Foundation Biotechnology Resource Laboratory, Department of Molecular Biophysics and Biochemistry, New Haven, CT 06520-8057, USA
| | - Patty J Lee
- Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520-8057, USA
| | - Praveen Mannam
- Pulmonary, Critical Care and Sleep Medicine, Department of Internal Medicine, Yale University School of Medicine, New Haven, CT 06520-8057, USA
| |
Collapse
|
5
|
Morin N, Di Paolo T. Pharmacological Treatments Inhibiting Levodopa-Induced Dyskinesias in MPTP-Lesioned Monkeys: Brain Glutamate Biochemical Correlates. Front Neurol 2014; 5:144. [PMID: 25140165 PMCID: PMC4122180 DOI: 10.3389/fneur.2014.00144] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 07/18/2014] [Indexed: 12/21/2022] Open
Abstract
Anti-glutamatergic drugs can relieve Parkinson’s disease (PD) symptoms and decrease l-3,4-dihydroxyphenylalanine (l-DOPA)-induced dyskinesias (LID). This review reports relevant studies investigating glutamate receptor subtypes in relation to motor complications in PD patients and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned monkeys. Antagonists of the ionotropic glutamate receptors, such as N-methyl-d-aspartate (NMDA) and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors, display antidyskinetic activity in PD patients and animal models such as the MPTP monkey. Metabotropic glutamate 5 (mGlu5) receptor antagonists were shown to reduce the severity of LID in PD patients as well as in already dyskinetic non-human primates and to prevent the development of LID in de novo treatments in non-human primates. An increase in striatal post-synaptic NMDA, AMPA, and mGlu5 receptors is documented in PD patients and MPTP monkeys with LID. This increase can be prevented in MPTP monkeys with the addition of a specific glutamate receptor antagonist to the l-DOPA treatment and also with drugs of various pharmacological specificities suggesting multiple receptor interactions. This is yet to be well documented for presynaptic mGlu4 and mGlu2/3 and offers additional new promising avenues.
Collapse
Affiliation(s)
- Nicolas Morin
- Neuroscience Research Unit, Centre de Recherche du CHU de Québec , Quebec City, QC , Canada ; Faculty of Pharmacy, Laval University , Quebec City, QC , Canada
| | - Thérèse Di Paolo
- Neuroscience Research Unit, Centre de Recherche du CHU de Québec , Quebec City, QC , Canada ; Faculty of Pharmacy, Laval University , Quebec City, QC , Canada
| |
Collapse
|
6
|
Modeling dyskinesia in animal models of Parkinson disease. Exp Neurol 2014; 256:105-16. [DOI: 10.1016/j.expneurol.2013.01.024] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 01/12/2013] [Accepted: 01/21/2013] [Indexed: 01/23/2023]
|
7
|
Morin N, Jourdain VA, Morissette M, Grégoire L, Di Paolo T. Long-term treatment with l-DOPA and an mGlu5 receptor antagonist prevents changes in brain basal ganglia dopamine receptors, their associated signaling proteins and neuropeptides in parkinsonian monkeys. Neuropharmacology 2014; 79:688-706. [PMID: 24456747 DOI: 10.1016/j.neuropharm.2014.01.014] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 12/11/2013] [Accepted: 01/07/2014] [Indexed: 01/11/2023]
Abstract
Brain glutamate overactivity is well documented in Parkinson's disease (PD) and antiglutamatergic drugs decrease L-3,4-dihydroxyphenylalanine (l-DOPA)-induced dyskinesias (LID); the implication of dopamine neurotransmission is not documented in this anti-LID activity. Therefore, we evaluated changes of dopamine receptors, their associated signaling proteins and neuropeptides mRNA, in normal control monkeys, in saline-treated 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-lesioned monkeys and in L-DOPA-treated MPTP monkeys, without or with an adjunct treatment to reduce the development of LID: 2-methyl-6-(phenylethynyl)pyridine (MPEP), the prototypal metabotropic glutamate 5 (mGlu5) receptor antagonist. All de novo treatments were administered for 1 month and the animals were sacrificed thereafter. MPTP monkeys treated with l-DOPA + MPEP developed significantly less LID than MPTP monkeys treated with l-DOPA alone. [(3)H]SCH-23390 specific binding to D1 receptors of all MPTP monkeys was decreased as compared to controls in the basal ganglia and no difference was observed between all MPTP groups, while striatal D1 receptor mRNA levels remained unchanged. [(3)H]raclopride specific binding to striatal D2 receptors and mRNA levels of D2 receptors were increased in MPTP monkeys compared to controls; l-DOPA treatment reduced this binding in MPTP monkeys while it remained elevated with the l-DOPA + MPEP treatment. Striatal [(3)H]raclopride specific binding correlated positively with D2 receptor mRNA levels of all MPTP-lesioned monkeys. Striatal preproenkephalin/preprodynorphin mRNA levels and phosphorylated ERK1/2 and Akt/GSK3β levels increased only in L-DOPA-treated MPTP monkeys as compared to controls, saline treated-MPTP and l-DOPA + MPEP treated MPTP monkeys. Hence, reduction of development of LID with MPEP was associated with changes in D2 receptors, their associated signaling proteins and neuropeptides.
Collapse
Affiliation(s)
- Nicolas Morin
- Faculty of Pharmacy, Université Laval, Quebec City G1K 7P4, Canada; Neuroscience Research Unit, Centre de recherche du CHU de Québec, Quebec City G1V 4G2, Canada
| | - Vincent A Jourdain
- Faculty of Pharmacy, Université Laval, Quebec City G1K 7P4, Canada; Neuroscience Research Unit, Centre de recherche du CHU de Québec, Quebec City G1V 4G2, Canada
| | - Marc Morissette
- Neuroscience Research Unit, Centre de recherche du CHU de Québec, Quebec City G1V 4G2, Canada
| | - Laurent Grégoire
- Neuroscience Research Unit, Centre de recherche du CHU de Québec, Quebec City G1V 4G2, Canada
| | - Thérèse Di Paolo
- Faculty of Pharmacy, Université Laval, Quebec City G1K 7P4, Canada; Neuroscience Research Unit, Centre de recherche du CHU de Québec, Quebec City G1V 4G2, Canada.
| |
Collapse
|
8
|
Non-classical effects of estradiol on cAMP responsive element binding protein phosphorylation in gonadotropin-releasing hormone neurons: mechanisms and role. Front Neuroendocrinol 2014; 35:31-41. [PMID: 23978477 DOI: 10.1016/j.yfrne.2013.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Revised: 07/29/2013] [Accepted: 08/12/2013] [Indexed: 12/17/2022]
Abstract
Gonadotropin-releasing hormone (GnRH) is produced by a heterogenous neuronal population in the hypothalamus to control pituitary gonadotropin production and reproductive function in all mammalian species. Estradiol is a critical component for the communication between the gonads and the central nervous system. Resolving the mechanisms by which estradiol modulates GnRH neurons is critical for the understanding of how fertility is regulated. Extensive studies during the past decades have provided compelling evidence that estradiol has the potential to alter the intracellular signal transduction mechanisms. The common target of many signaling pathways is the phosphorylation of a key transcription factor, the cAMP response element binding protein (CREB). This review first addresses the aspects of estradiol action on CREB phosphorylation (pCREB) in GnRH neurons. Secondly, this review considers the receptors and signaling network that regulates estradiol's action on pCREB within GnRH neurons and finally it summarizes the physiological significance of CREB to estrogen feedback.
Collapse
|
9
|
Gaballah M, Slisz M, Hutter-Lobo D. Role of JNK-1 regulation in the protection of contact-inhibited fibroblasts from oxidative stress. Mol Cell Biochem 2012; 359:105-13. [PMID: 21822690 PMCID: PMC3219803 DOI: 10.1007/s11010-011-1004-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Accepted: 07/19/2011] [Indexed: 01/04/2023]
Abstract
The molecular signaling events leading to protection from oxidative stress-induced apoptosis upon contact inhibition have not been fully investigated. Previous research has indicated a role for mitogen-activated protein kinases (MAPKs) in the regulation of contact inhibition, and these proteins have also been associated with cell cycle regulation and stress-induced apoptosis. The potential role of the MAPK JNK-1 in the stress-response of actively proliferating and contact-inhibited cells was investigated. Actively proliferating normal fibroblasts (BJ) and fibrosarcoma cells (HT-1080) were stressed with H2O2, and levels of activated JNK-1 and cleaved PARP were ascertained. Similarly, these results were compared with levels of activated JNK-1 and cleaved PARP detected in H2O2-stressed confluent fibrosarcoma or contact-inhibited fibroblast cells. Contact-inhibited fibroblasts were protected from apoptosis in comparison to subconfluent fibroblasts, concurrent with decreased JNK-1 activation. Increased culture density of fibrosarcoma cells was not protective against apoptosis, and these cells did not demonstrate density-dependent alterations in the JNK-1 stress response. This decreased activation of JNK-1 in stressed, contact-inhibited cells did not appear to be dependent upon increased expression of MKP-1; however, over-expression of MKP-1 was sufficient to result in a slight decrease in H2O2-stimulated PARP cleavage. Increasing the antioxidant capacity of fibroblasts through NAC-treatment not only lessened H2O2-stimulated JNK-1 activation, but also did not influence the expression of MKP-1. Taken together, these results suggest that regulation of negative regulation of JNK-1 upon contact inhibition is protective against apoptosis, and that this regulation is independent of MKP-1.
Collapse
Affiliation(s)
- Marian Gaballah
- Department of Biology, Monmouth University, West Long Branch, NJ 07764
| | - Michael Slisz
- Department of Biology, Monmouth University, West Long Branch, NJ 07764
| | | |
Collapse
|
10
|
Helmbrecht K, Zeise E, Rensing L. Chaperones in cell cycle regulation and mitogenic signal transduction: a review. Cell Prolif 2008; 33:341-65. [PMID: 11101008 PMCID: PMC6496586 DOI: 10.1046/j.1365-2184.2000.00189.x] [Citation(s) in RCA: 211] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Chaperones/heat shock proteins (HSPs) of the HSP90 and HSP70 families show elevated levels in proliferating mammalian cells and a cell cycle-dependent expression. They transiently associate with key molecules of the cell cycle control system such as Cdk4, Wee-1, pRb, p53, p27/Kip1 and are involved in the nuclear localization of regulatory proteins. They also associate with viral oncoproteins such as SV40 super T, large T and small t antigen, polyoma large and middle S antigen and EpsteinBarr virus nuclear antigen. This association is based on a J-domain in the viral proteins and may assist their targeting to the pRb/E2F complex. Small HSPs and their state of phosphorylation and oligomerization also seem to be involved in proliferation and differentiation. Chaperones/HSPs thus play important roles within cell cycle processes. Their exact functioning, however, is still a matter of discussion. HSP90 in particular, but also HSP70 and other chaperones associate with proteins of the mitogen-activated signal cascade, particularly with the Src kinase, with tyrosine receptor kinases, with Raf and the MAP-kinase activating kinase (MEK). This apparently serves the folding and translocation of these proteins, but possibly also the formation of large immobilized complexes of signal transducing molecules (scaffolding function).
Collapse
Affiliation(s)
- K Helmbrecht
- Institute of Cell Biology, Biochemistry and Biotechnology, University of Bremen, Germany
| | | | | |
Collapse
|
11
|
Pelech S, Jelinkova L, Susor A, Zhang H, Shi X, Pavlok A, Kubelka M, Kovarova H. Antibody Microarray Analyses of Signal Transduction Protein Expression and Phosphorylation during Porcine Oocyte Maturation. J Proteome Res 2008; 7:2860-71. [DOI: 10.1021/pr800082a] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Steven Pelech
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Lucie Jelinkova
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Andrej Susor
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Hong Zhang
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Xiaoqing Shi
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Antonin Pavlok
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Michal Kubelka
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| | - Hana Kovarova
- Kinexus Bioinformatics Corporation, Suite 1, 8755 Ash Street, Vancouver, BC, Canada V6P 6T3, Department of Medicine, University of British Columbia, Vancouver, BC, Canada, and Department of Reproductive and Developmental Biology, Institute of Animal Physiology and Genetics, Rumburska 89, Libechov, Czech Republic
| |
Collapse
|
12
|
Meng J, Shi Y, Zhao X, Zhou J, Zheng Y, Tang R, Ma G, Zhu X, He Z, Wang Z, Xu Y, Feng G, He L. No significant association between the genetic polymorphisms in the GSK-3 beta gene and schizophrenia in the Chinese population. J Psychiatr Res 2008; 42:365-70. [PMID: 17368486 DOI: 10.1016/j.jpsychires.2007.01.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/20/2006] [Revised: 01/06/2007] [Accepted: 01/17/2007] [Indexed: 10/23/2022]
Abstract
The GSK-3 beta gene encodes a protein kinase which is abundant in the brain, and its product is involved in signal transduction cascades of neuronal cell development, energy metabolism and body pattern formation. Previous studies have suggested that GSK-3 beta might act as a potential candidate locus for schizophrenia susceptibility. We genotyped six SNPs within the gene and conducted a case-control study involving 329 schizophrenic patients and 288 healthy subjects in the Chinese population. We examined allele and genotype frequencies and haplotype distributions in the subtype of paranoid schizophrenic patients as well as schizophrenic subjects in general. Our results fail to replicate the association of the GSK-3 beta gene with susceptibility to schizophrenia in the Chinese population.
Collapse
Affiliation(s)
- Junwei Meng
- Bio-X Center, Shanghai Jiao Tong University, Haoran Building, 1954 Huashan Road, Shanghai 200030, PR China
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Slisz M, Rothenberger E, Hutter D. Attenuation of p38 MAPK activity upon contact inhibition in fibroblasts. Mol Cell Biochem 2007; 308:65-73. [PMID: 17906919 DOI: 10.1007/s11010-007-9613-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2007] [Accepted: 09/13/2007] [Indexed: 12/27/2022]
Abstract
The molecular events, which govern growth control upon contact inhibition have not yet been clearly defined. Previous work has indicated that there is an increase in the expression of mitogen-activated protein kinase phosphatases (MKPs) upon the attainment of contact inhibition in normal fibroblasts, concurrently with a decrease in ERK activity. To investigate the potential role of p38 and JNK in the transition to a contact-inhibited state, normal human fibroblasts (BJ) were grown to subconfluent and confluent densities. The total levels and phosphorylation states of p38 and JNK were assayed, and were compared to protein levels seen in HT-1080 fibrosarcoma cells, which lack contact-inhibited growth control. Activation of JNK was not apparent in these cells, though p38 was found to be active in proliferating cells, but attenuated in contact-inhibited cultures. Such fluctuations in p38 activity were not seen in cultures of fibrosarcoma cells of increasing density. This alteration in p38 activity was also reflected by attenuated activation of the downstream transcription factor ATF-2 upon contact inhibition. Overexpression of MKP-1 in fibrosarcoma cells and fibroblasts reduced proliferation, while expression of a phosphatase-resistant p38 protein (p38(N316)) enhanced proliferation of normal fibroblasts. Taken together, these results suggest the involvement of negative regulation of p38 in contact-inhibited growth control.
Collapse
Affiliation(s)
- Michael Slisz
- Department of Biology, Monmouth University, 400 Cedar Avenue, West Long Branch, NJ 07764, USA
| | | | | |
Collapse
|
14
|
Sun JY, Wang JF, Zi NT, Jing MY, Weng XY. Gene expression profiles analysis of the growing rat liver in response to different zinc status by cDNA microarray analysis. Biol Trace Elem Res 2007; 115:169-85. [PMID: 17435260 DOI: 10.1007/bf02686028] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2006] [Revised: 06/01/2006] [Accepted: 06/16/2006] [Indexed: 10/22/2022]
Abstract
The effects of zinc on growing rats were characterized using the dietary zinc-deficient (ZD) and Zinc-overdose (ZO) models. Zinc deficiency had negative effects on the host final body weight and liver zinc content, whereas zinc overdose had positive effects. In order to identify the molecular changes in the liver responding to dietary zinc status, cDNA microarrays were used to analyze the expression pattern of 9753 genes in the livers of rats fed ZD and ZO diet for 6 wk, compared with zinc-adequate ZA. The mRNA levels for 62 genes were affected significantly by the ZD diet, whereas 66 gene transcriptions were markedly changed in the ZO diet. Those predominant gene products involved in nitrogen metabolism (glutaminase), carbohydrate metabolism (aldolase), lipid metabolism (stearoyl-CoA desaturase), growth (insulin-like growth factor-binding protein), transcription and translation (zinc-finger protein), immune (natural-killer cell), signal transduction (mitogen- activated protein kinase), and ion transportation (ATPase Na+/K+ transporting peptide) were clustered. In conclusion, a number of mammalian genes related to zinc in the liver were identified. The characterization of the genes and their products will allow a more comprehensive analysis of the role of zinc in metabolism. Furthermore, the mRNA identified could be useful in establishing the mechanisms of zinc in the pleiotropic metabolisms in vivo.
Collapse
Affiliation(s)
- J Y Sun
- The Key Laboratory of Molecular Animal Nutrition, Ministry of Education, College of Animal, Zhejiang University, Hangzhou, PR China
| | | | | | | | | |
Collapse
|
15
|
Wayne J, Sielski J, Rizvi A, Georges K, Hutter D. ERK regulation upon contact inhibition in fibroblasts. Mol Cell Biochem 2006; 286:181-9. [PMID: 16467968 DOI: 10.1007/s11010-005-9089-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2005] [Accepted: 11/23/2005] [Indexed: 10/25/2022]
Abstract
Despite the understanding of the importance of mitogen-activated protein (MAP) kinase activation in the stimulation of growth, little is known about the role of MAP kinase regulation during contact inhibited growth control. To investigate the role of the MAP kinase extracellular signal-regulated kinase (ERK) during the transition to a contact inhibited state, cultures of normal fibroblasts (BJ) were grown to different stages of confluency. The levels of MAP kinase phosphatase (MKP) expression and the amount of active ERK and MAP ERK kinase (MEK) in these cultures were assessed through western blot analysis and were compared to fibrosarcoma cell cultures (HT-1080), which lack contact inhibition. In normal fibroblasts, the amounts of active MEK and ERK decline at contact inhibition, concurrently with a rise in MKP-1, MKP-2, and MKP-3 protein levels. In contrast, fibrosarcoma cells appear to lack density-dependent regulation of the ERK pathway. Additionally, altering the redox environment of fibrosarcoma cells to a less reducing state, as seen during contact inhibition, results in increased MKP-1 expression. Taken together, these results suggest that the altered redox environment upon contact inhibition may contribute to the regulation of ERK inactivation by MKPs.
Collapse
Affiliation(s)
- Joshua Wayne
- Department of Biology, Monmouth University, West Long Branch, NJ 07764, USA
| | | | | | | | | |
Collapse
|
16
|
Kozlovsky N, Nadri C, Agam G. Low GSK-3beta in schizophrenia as a consequence of neurodevelopmental insult. Eur Neuropsychopharmacol 2005; 15:1-11. [PMID: 15572268 DOI: 10.1016/j.euroneuro.2004.02.003] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2003] [Revised: 11/11/2003] [Accepted: 02/03/2004] [Indexed: 10/26/2022]
Abstract
Glycogen synthase kinase-3 (GSK-3) is a protein kinase highly abundant in brain and involved in signal transduction cascades, particularly neurodevelopment. Its activity and protein levels have been reported to be over 40% lower in postmortem frontal cortex of schizophrenic patients. GSK-3beta in occipital cortex of schizophrenic patients was not reduced, suggesting regional specificity. There was no reduction in GSK-3beta protein levels in fresh and immortalized lymphocytes and both GSK-3 activity and GSK-3beta mRNA levels in fresh lymphocytes from schizophrenic patients. In the schizophrenia-related neonatal ventral hippocampal lesion rat model, we measured GSK-3beta protein levels and GSK-3 activity in the frontal cortex. GSK-3beta protein levels in lesioned rats were significantly lower than in sham rats, favoring perinatal insult as a cause of low GSK-3beta in schizophrenia. Taken together, these studies suggest that low GSK-3 in postmortem brain of schizophrenic patients is a late consequence of perinatal neurodevelopmental insult in schizophrenia. In rats, acute or chronic cold restraint stress did not change GSK-3beta protein levels. Chronic treatment of rats with lithium, valproate, haloperidol or clozapine did not change rat cortical GSK-3beta protein levels ex vivo, supporting the concept that low GSK-3beta in schizophrenia is not secondary to stress or drug treatment. Our initial findings of low GSK-3beta protein levels in postmortem brain have been replicated by another group. Our own group has found additionally that GSK-3beta mRNA levels were 40% lower in postmortem dorsolateral prefrontal cortex (DLPFC) of schizophrenic patients, supporting our previous findings. Further studies will be aimed at determining whether nonspecific neonatal damage or only specific factors cause low GSK-3 as a late effect. We plan to study whether low GSK-3beta activity is associated with biochemical effects such as elevated beta-catenin levels.
Collapse
Affiliation(s)
- Nitsan Kozlovsky
- Stanley Research Center, Faculty of Health Sciences, Ben Gurion University of the Negev and Mental Health Center, Beersheba, Israel
| | | | | |
Collapse
|
17
|
Zhang M, Li J, Chakrabarty P, Bu B, Vincent I. Cyclin-dependent kinase inhibitors attenuate protein hyperphosphorylation, cytoskeletal lesion formation, and motor defects in Niemann-Pick Type C mice. THE AMERICAN JOURNAL OF PATHOLOGY 2004; 165:843-53. [PMID: 15331409 PMCID: PMC1618588 DOI: 10.1016/s0002-9440(10)63347-0] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Dysregulation of cyclin-dependent kinases (cdks) and cytoskeletal protein hyperphosphorylation characterizes a subset of human neurodegenerative diseases, including Alzheimer's disease, amyotrophic lateral sclerosis, and Niemann-Pick Type C (NPC). It is thought that these cytoskeletal changes lead eventually to development of hallmark cytoskeletal lesions such as neurofibrillary tangles and axonal spheroids. Although many studies support an involvement of cdks in these neurodegenerative cascades, it is not known whether cdk activity is essential. The naturally occurring npc-1 mutant mouse mimics human NPC, in displaying activation of cdk5, mitotic cdc2, and cdk4, with concomitant cytoskeletal pathology and neurodegeneration. We availed of this model and specific pharmacological inhibitors of cdk activity, to determine whether cdks are necessary for NPC neuropathology. The inhibitors were infused intracerebroventricularly for a 2-week period, initiated at a pathologically incipient stage. While an inactive stereoisomer, iso-olomoucine, was ineffective, two potent inhibitors, roscovitine and olomoucine, attenuated significantly the hyperphosphorylation of neurofilament, tau, and mitotic proteins, reduced the number of spheroids, modulated Purkinje neuron death, and ameliorated motor defects in npc mice. These results suggest that cdk activity is required for neuropathology and subsequent motor impairment in NPC. Studies aimed at knocking down individual cdks in these mice will help identify the specific cdk(s) that are essential, and delineate their precise roles in the neurodegenerative process.
Collapse
Affiliation(s)
- Min Zhang
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | | | | | | | | |
Collapse
|
18
|
Amar S, Jones BC, Nadri C, Kozlovsky N, Belmaker RH, Agam G. Genetic correlational analysis of glycogen synthase kinase-3 beta and prepulse inhibition in inbred mice. GENES BRAIN AND BEHAVIOR 2004; 3:178-80. [PMID: 15140013 DOI: 10.1111/j.1601-183x.2004.00065.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
In humans, GSK-3 beta activity is diminished in schizophrenic patients as is prepulse inhibition of the startle response (PPI). We performed a genetic correlational analysis between published PPI values and frontal cortex GSK-3 activity analyzed in our laboratory in 10 inbred mouse strains. This methodology could indicate relevant parameters for study in an animal model. Indeed, we obtained significant correlations between the enzyme's activity and PPI measured by two different methods. This may indicate that investigation of the genetics of GSK-3 beta regulation holds promise for understanding some of the biochemical underpinnings of schizophrenia.
Collapse
Affiliation(s)
- S Amar
- Stanley Foundation Research Center and Department of Clinical Biochemistry, Faculty of Health Sciences, Ben Gurion University of the Negev, Beersheva, Israel
| | | | | | | | | | | |
Collapse
|
19
|
Young LT, Bezchlibnyk YB, Chen B, Wang JF, MacQueen GM. Amygdala cyclic adenosine monophosphate response element binding protein phosphorylation in patients with mood disorders: effects of diagnosis, suicide, and drug treatment. Biol Psychiatry 2004; 55:570-7. [PMID: 15013825 DOI: 10.1016/j.biopsych.2003.10.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2003] [Revised: 10/27/2003] [Accepted: 10/30/2003] [Indexed: 11/16/2022]
Abstract
BACKGROUND Signal transduction abnormalities have been identified in patients with bipolar (BD) and major depressive (MDD) disorders and are targets for lithium and antidepressant drugs. A key downstream target for signal transduction pathways is the transcription factor cyclic adenosine monophosphate (cAMP) response element binding protein (CREB). Therefore, we measured the levels of phosphorylated CREB (pCREB) in the amygdala, a region critical to emotional processing and important in the pathophysiology of both BD and MDD. METHODS Human postmortem amygdala sections were generously provided by the Stanley Foundation Neuropathology Consortium. Samples consisted of subjects with MDD, BD, schizophrenia (SCZ), and nonpsychiatric-nonneurologic comparison subjects (n = 15 per group). Levels of pCREB were measured by immunohistochemistry, relative to total cell number. RESULTS There were no differences between diagnostic groups--control subjects and subjects with BD, MDD, or SCZ--but increased numbers of pCREB stained cells were found in several amygdalar nuclei in subjects who had died by suicide. In contrast, patients treated with lithium at the time of death had significantly lower pCREB levels in the same region. CONCLUSIONS These results suggest that CREB activity may be an important factor in the neurobiology of suicide and the well-documented antisuicidal effect of lithium.
Collapse
Affiliation(s)
- L Trevor Young
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario, Canada
| | | | | | | | | |
Collapse
|
20
|
Vlahos R, Lee KS, Guida E, Fernandes DJ, Wilson JW, Stewart AG. Differential inhibition of thrombin- and EGF-stimulated human cultured airway smooth muscle proliferation by glucocorticoids. Pulm Pharmacol Ther 2003; 16:171-80. [PMID: 12749833 DOI: 10.1016/s1094-5539(02)00183-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The present study compared the effects of glucocorticoids on thrombin- and EGF-stimulated proliferation in human cultured airway smooth muscle (ASM) to identify pathways that may be differentially regulated by glucocorticoids. Mitogenic responses to thrombin were inhibited by extracellular-regulated kinase (ERK 1/2) and phosphoinositide 3-kinase (PI3K) inhibitors, whereas mitogenic responses to EGF were inhibited by ERK 1/2 and PI3K inhibitors as well as by the p38 mitogen activated protein kinase inhibitor, SB203580 (10 microM). Mitogenic responses to thrombin were more sensitive to inhibition by dexamethasone (Dex) or fluticasone propionate (FP) than were those to EGF. Elevated cyclin D1 protein and mRNA levels induced by thrombin and EGF were attenuated equally by glucocorticoids. The protein or mRNA levels of the cyclin-dependent kinase inhibitors (cdki) p21(Cip1), p27(Kip1) were unaffected by Dex treatment of ASM cells treated with mitogens. The resistance of EGF-induced proliferation to inhibition by glucocorticoids is not associated with a failure to regulate cyclin D1 induction, nor does it appear to be explained by differential regulation of the levels of the cdki's, p21(Cip1) and p27(Kip1).
Collapse
Affiliation(s)
- Ross Vlahos
- Department of Pharmacology, University of Melbourne, Melbourne, Vic. 3010, Australia
| | | | | | | | | | | |
Collapse
|
21
|
Gilbert TL, Griffin N, Moffett J, Ritz MC, George FR. The Provant Wound Closure System induces activation of p44/42 MAP kinase in normal cultured human fibroblasts. Ann N Y Acad Sci 2002; 961:168-71. [PMID: 12081892 DOI: 10.1111/j.1749-6632.2002.tb03076.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Terri L Gilbert
- Regenesis Biomedical Inc., 1435 N Hayden Road, Scottsdale, AZ 85257, USA
| | | | | | | | | |
Collapse
|
22
|
Bezchlibnyk Y, Young LT. The neurobiology of bipolar disorder: focus on signal transduction pathways and the regulation of gene expression. CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2002; 47:135-48. [PMID: 11926075 DOI: 10.1177/070674370204700203] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE This article presents an overview of signal transduction pathways and reviews the research undertaken to study these systems in clinically relevant samples from patients with bipolar disorder (BD). METHOD We reviewed the published findings from studies of postmortem brain tissue and blood samples from patients with BD. RESULTS Although the exact biochemical abnormalities have yet to be identified, the presented findings strongly suggest that BD may be due, at least in part, to abnormalities in signal transduction mechanisms. In particular, altered levels or function, or both, of G-protein alpha subunits and effector molecules such as protein kinase A (PKA) and protein kinase C (PKC) have consistently been associated with BD both in peripheral cells and in postmortem brain tissue, while more recent studies implicate disruption in novel second-messenger cascades, such as the ERK/MAPK pathway. CONCLUSIONS Despite the difficulties inherent in biochemical studies of clinically relevant tissue samples, numerous investigations have illuminated the signal transduction mechanisms in patients with BD. These studies also suggest that BD may be due to the interaction of many abnormalities. In this context, novel techniques enabling the study of gene expression promise to assist in untangling these complex interactions, through visualizing the end result of these changes at the level of gene transcription.
Collapse
Affiliation(s)
- Yarema Bezchlibnyk
- Department of Psychiatry and Behavioural Neurosciences, McMaster University, Hamilton, Ontario
| | | |
Collapse
|
23
|
Rutter J, Michnoff CH, Harper SM, Gardner KH, McKnight SL. PAS kinase: an evolutionarily conserved PAS domain-regulated serine/threonine kinase. Proc Natl Acad Sci U S A 2001; 98:8991-6. [PMID: 11459942 PMCID: PMC55361 DOI: 10.1073/pnas.161284798] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
PAS domains regulate the function of many intracellular signaling pathways in response to both extrinsic and intrinsic stimuli. PAS domain-regulated histidine kinases are common in prokaryotes and control a wide range of fundamental physiological processes. Similarly regulated kinases are rare in eukaryotes and are to date completely absent in mammals. PAS kinase (PASK) is an evolutionarily conserved gene product present in yeast, flies, and mammals. The amino acid sequence of PASK specifies two PAS domains followed by a canonical serine/threonine kinase domain, indicating that it might represent the first mammalian PAS-regulated protein kinase. We present evidence that the activity of PASK is regulated by two mechanisms. Autophosphorylation at two threonine residues located within the activation loop significantly increases catalytic activity. We further demonstrate that the N-terminal PAS domain is a cis regulator of PASK catalytic activity. When the PAS domain-containing region is removed, enzyme activity is significantly increased, and supplementation of the purified PAS-A domain in trans selectively inhibits PASK catalytic activity. These studies define a eukaryotic signaling pathway suitable for studies of PAS domains in a purified in vitro setting.
Collapse
Affiliation(s)
- J Rutter
- Department of Biochemistry, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas, TX 75390-9152, USA
| | | | | | | | | |
Collapse
|
24
|
Cha H, Shapiro P. Tyrosine-phosphorylated extracellular signal--regulated kinase associates with the Golgi complex during G2/M phase of the cell cycle: evidence for regulation of Golgi structure. J Cell Biol 2001; 153:1355-67. [PMID: 11425867 PMCID: PMC2150730 DOI: 10.1083/jcb.153.7.1355] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Phosphorylation of the extracellular signal-regulated kinases (ERKs) on tyrosine and threonine residues within the TEY tripeptide motif induces ERK activation and targeting of substrates. Although it is recognized that phosphorylation of both residues is required for ERK activation, it is not known if a single phosphorylation of either residue regulates physiological functions. In light of recent evidence indicating that ERK proteins regulate substrate function in the absence of ERK enzymatic activity, we have begun to examine functional roles for partially phosphorylated forms of ERK. Using phosphorylation site--specific ERK antibodies and immunofluorescence, we demonstrate that ERK phosphorylated on the tyrosine residue (pY ERK) within the TEY activation sequence is found constitutively in the nucleus, and localizes to the Golgi complex of cells that are in late G2 or early mitosis of the cell cycle. As cells progress through metaphase and anaphase, pY ERK localization to Golgi vesicles is most evident around the mitotic spindle poles. During telophase, pY ERK associates with newly formed Golgi vesicles but is not found on there after cytokinesis and entry into G1. Increased ERK phosphorylation causes punctate distribution of several Golgi proteins, indicating disruption of the Golgi structure. This observation is reversible by overexpression of a tyrosine phosphorylation--defective ERK mutant, but not by a kinase-inactive ERK2 mutant that is tyrosine phosphorylated. These data provide the first evidence that pY ERK and not ERK kinase activity regulates Golgi structure and may be involved in mitotic Golgi fragmentation and reformation.
Collapse
Affiliation(s)
- Hyukjin Cha
- Department of Pharmaceutical Sciences, University of Maryland, School of Pharmacy, Baltimore, Maryland 21201
| | - Paul Shapiro
- Department of Pharmaceutical Sciences, University of Maryland, School of Pharmacy, Baltimore, Maryland 21201
| |
Collapse
|
25
|
Hayashi M, Tapping RI, Chao TH, Lo JF, King CC, Yang Y, Lee JD. BMK1 mediates growth factor-induced cell proliferation through direct cellular activation of serum and glucocorticoid-inducible kinase. J Biol Chem 2001; 276:8631-4. [PMID: 11254654 DOI: 10.1074/jbc.c000838200] [Citation(s) in RCA: 102] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activation of the mammalian mitogen-activated protein kinase known as BMK1 is required for growth factor-induced cell proliferation. To understand the mechanism by which BMK1 mediates this cellular response, this kinase was used as bait in a yeast two-hybrid-based library screening. Here, we report the identification of serum and glucocorticoid-inducible kinase (SGK) as a cellular protein that physically interacts with BMK1. During growth factor-induced cell stimulation, BMK1 activates SGK by phosphorylation at serine 78. This BMK1-mediated phosphorylation event is necessary for the activation of SGK and, more importantly, for cell proliferation induced by growth factors.
Collapse
Affiliation(s)
- M Hayashi
- Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA
| | | | | | | | | | | | | |
Collapse
|
26
|
Strohm C, Barancik T, Brühl ML, Kilian SA, Schaper W. Inhibition of the ER-kinase cascade by PD98059 and UO126 counteracts ischemic preconditioning in pig myocardium. J Cardiovasc Pharmacol 2000; 36:218-29. [PMID: 10942164 DOI: 10.1097/00005344-200008000-00012] [Citation(s) in RCA: 76] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Our previous studies suggested a protective role of the extracellular signal-regulated kinases (ERKs) cascade in ischemic preconditioning (IP) in the porcine heart. To test this hypothesis further, we studied the influence of the novel specific inhibitors of mitogen-activated protein kinase kinases (MEK 1/2) PD98059 (PD) and UO126 (UO) in IP. The substances were infused intramyocardially and UO also systemically in anesthetized, ventilated, open-chested, male pigs. The local intramyocardial PD and UO infusions occurred before IP and during both reperfusion (RP) phases of IP via four pairs of needles (three pairs verum, one solvent) into the risk area (RA). The IP design included two cycles of 10-min left anterior descending artery (LAD) occlusion and 10 min RP, followed by 40 min of occlusion (index ischemia) and of 60 min of RP. Biopsies of the areas of drug infusion were taken after the second RP cycle of IP. By Western blot analysis, the phosphorylation of ERK 1/2 and of the downstream transcription factor Elk-1 were measured, and the activities of the ERKs were tested by in gel phosphorylation. Only small infarcts were detected in the control group animals with the IP period [infarct size (IS), infarct area/risk area; IS, 2.5+/-0.1%]. Significant wedge-shaped infarcts were seen around the area of the PD and UO infusions. The effects of PD and UO were concentration dependent. The maximal dose of UO126 (7.5 mg systemically) was associated with an IS of 68.7+/-2.0%. At the end of IP, we observed a significant increase in phosphorylation and activities of ERKs. PD (50 microM) induced a 50% inhibition of ERK-1 and 56% of ERK-2 activities. Phosphorylated ERK-1 and ERK-2 were decreased after microinfusion of both PD and UO (50 microM). Microinfusion of 50 microM PD also significantly decreased the phosphorylation of Elk-1 (to 59.2+/-8.3% of control conditions). We demonstrate for the first time in vivo that the inhibition of ERKs by PD and UO results in a complete cancellation of IP.
Collapse
Affiliation(s)
- C Strohm
- Department of Experimental Cardiology, Max-Planck-Institute for Physiological and Clinical Research, Bad Nauheim, Germany
| | | | | | | | | |
Collapse
|
27
|
Abstract
The inhibition of growth is a cardinal symptom of zinc deficiency. In animals fed a zinc-inadequate diet, both food intake and growth are reduced within 4-5 d. Despite the concomitant reduction in food intake and growth, reduced energy intake is not the limiting factor in growth, because force-feeding a zinc-inadequate diet to animals fails to maintain growth. Hence, food intake and growth appear to be regulated by zinc through independent, although well coordinated, mechanisms. Despite the long-term study of zinc metabolism, the first limiting role of zinc in cell proliferation remains undefined. Zinc participates in the regulation of cell proliferation in several ways; it is essential to enzyme systems that influence cell division and proliferation. Removing zinc from the extracellular milieu results in decreased activity of deoxythymidine kinase and reduced levels of adenosine(5')tetraphosphate(5')-adenosine. Hence, zinc may directly regulate DNA synthesis through these systems. Zinc also influences hormonal regulation of cell division. Specifically, the pituitary growth hormone (GH)-insulin-like growth factor-I (IGF-I) axis is responsive to zinc status. Both increased and decreased circulating concentrations of GH have been observed in zinc deficiency, although circulating IGF-I concentrations are consistently decreased. However, growth failure is not reversed by maintaining either GH or IGF-I levels through exogenous administration, which suggests the defect occurs in hormone signaling. Zinc appears to be essential for IGF-I induction of cell proliferation; the site of regulation is postreceptor binding. Overall, the evidence suggests that reduced zinc availability affects membrane signaling systems and intracellular second messengers that coordinate cell proliferation in response to IGF-I.
Collapse
Affiliation(s)
- R S MacDonald
- Nutritional Sciences Program, University of Missouri, Columbia, MO 65211, USA
| |
Collapse
|
28
|
Lefebvre DL, Charest DL, Yee A, Crawford BJ, Pelech SL. Characterization of fertilization-modulated myelin basic protein kinases from sea star: Regulation of Mapk. J Cell Biochem 1999. [DOI: 10.1002/(sici)1097-4644(19991101)75:2<272::aid-jcb10>3.0.co;2-j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
|
29
|
Luo J, Miller MW. Transforming growth factor beta1-regulated cell proliferation and expression of neural cell adhesion molecule in B104 neuroblastoma cells: differential effects of ethanol. J Neurochem 1999; 72:2286-93. [PMID: 10349837 DOI: 10.1046/j.1471-4159.1999.0722286.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The expression and activity of factors influencing early neuronal development are altered by ethanol. Such factors include growth factors, for example, platelet-derived growth factor and basic fibroblast growth factor (for cell proliferation), and cell adhesion molecules (for neuronal migration). One agent, transforming growth factor beta1 (TGFbeta1), may affect both events. We tested the hypothesis that ethanol alters myriad TGFbeta1-mediated activities [i.e., cell proliferation and neural cell adhesion molecule (N-CAM) expression] using B104 neuroblastoma cells. TGFbeta1 inhibited the proliferation of B104 cells as evidenced by decreases in cell number and [3H]thymidine ([3H]dT) incorporation. TGFbeta1 induced sustained activation of extracellular signal-regulated kinases (ERKs), which are part of the family of mitogen-activated protein kinases (MAPKs). Treatment with PD98059 (a MAPK kinase blocker) abolished TGFbeta1-regulated inhibition of [3H]dT incorporation. TGFbeta1-mediated growth inhibition was potentiated by ethanol exposure. Ethanol also produced prolonged activation of ERK, an effect that was partially eliminated by treatment with PD98059. On the other hand, TGFbeta1 up-regulated N-CAM expression, and this up-regulation was not affected by treatment with PD98059. Ethanol inhibited the TGFbeta1-induced up-regulation of N-CAM expression in a concentration-dependent manner. Thus, TGFbeta1 affects ERK-dependent cell proliferation and ERK-independent N-CAM expression in B104 cells. Both activities are sensitive to ethanol and may underlie the ethanol-induced alterations in the proliferation and migration of CNS neurons.
Collapse
Affiliation(s)
- J Luo
- Department of Psychiatry, University of Iowa College of Medicine, Iowa City 52242-1000, USA
| | | |
Collapse
|
30
|
Hanlon M, Sealy L. Ras regulates the association of serum response factor and CCAAT/enhancer-binding protein beta. J Biol Chem 1999; 274:14224-8. [PMID: 10318842 DOI: 10.1074/jbc.274.20.14224] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The serum response element (SRE) is a promoter element essential for transcriptional activation of immediate early genes, such as c-fos and early growth response-1, by mitogenic signals. Several transcription factors bind the SRE, including the serum response factor (SRF), the ternary complex factor, and the CCAAT/enhancer-binding protein beta (C/EBPbeta). The C/EBPbeta mRNA encodes three translation products of 38, 35, and 20 kDa. p35-C/EBPbeta activates transcription of the SRE in an SRF-dependent fashion, whereas p20-C/EBPbeta, which initiates at an internal in-frame methionine, lacks a transactivation domain and inhibits transcription. We show that SRF and C/EBPbeta interact in vivo through the DNA binding domain of SRF and the C terminus of C/EBPbeta common to p35/38 and p20. Therefore, like the ternary complex factor, C/EBPbeta may be recruited to the SRE not only by binding to the DNA, which is not a high affinity site, but also by protein-protein interactions with SRF. Strikingly, in both the mammalian two-hybrid assay and in vivo coimmunoprecipitations, the association of SRF and p35-C/EBPbeta but not p20-C/EBPbeta is dramatically stimulated by activated Ras. Furthermore, mutation of the threonine within a mitogen-activated protein kinase consensus motif in the C terminus of C/EBPbeta eliminates the response to Ras. These results suggest a new mechanism by which mitogenic signals may influence transcription activity of the SRE by selectively promoting protein-protein interactions between SRF and the transactivator p35-C/EBPbeta.
Collapse
Affiliation(s)
- M Hanlon
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA
| | | |
Collapse
|
31
|
Wagey RT, Krieger C. Abnormalities of protein kinases in neurodegenerative diseases. PROGRESS IN DRUG RESEARCH. FORTSCHRITTE DER ARZNEIMITTELFORSCHUNG. PROGRES DES RECHERCHES PHARMACEUTIQUES 1999; 51:133-83. [PMID: 9949861 DOI: 10.1007/978-3-0348-8845-5_4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
In neurodegenerative diseases such as ALS and AD there is evidence for abnormal regulation of protein kinases. In these diseases, altered activities and protein levels of several specific kinases suggest that abnormal phosphorylation is present and this aberrant phosphorylation may be involved in the pathogenesis of these diseases. The observation that regulation of the NMDA receptor ion channel is altered in tissue from ALS patients may arise from the abnormal phosphorylation state of the protein kinase regulating NMDA receptor function. Whether the abnormalities of these protein kinases is a primary event leading to altered receptor regulation or vice versa is still poorly understood. The seemingly multiple pathogenic mechanisms of ALS and AD create complexity in assessing a primary cause that may lead to cell death. The mechanisms causing cell death (apoptosis or necrosis) may be overlapping with integrated events among the components interacting and contributing to a final pathway for neuron death. Thus, evidence of impairment in protein kinase signalling in these diseases may be a primary cause, a secondary event, or a compensatory mechanism. To further study this issue, different model systems could be beneficial to obtain a better understanding of these diseases.
Collapse
Affiliation(s)
- R T Wagey
- Dept. of Medicine, University of British Columbia, Vancouver, Canada
| | | |
Collapse
|
32
|
Abstract
Multiple lines of evidence suggest that increased production and/or deposition of the beta-amyloid peptide, derived from the amyloid precursor protein, contributes to Alzheimer's disease. A growing list of neurotransmitters, growth factors, cytokines, and hormones have been shown to regulate amyloid precursor protein processing. Although traditionally thought to be mediated by activation of protein kinase C, recent data have implicated other signaling mechanisms in the regulation of this process. Moreover, novel mechanisms of regulation involving cholesterol-, apolipoprotein E-, and stress-activated pathways have been identified. As the phenotypic changes associated with Alzheimer's disease encompass many of these signaling systems, it is relevant to determine how altered cell signaling may be contributing to increasing brain amyloid burden. We review the myriad ways in which first messengers regulate amyloid precursor protein catabolism as well as the signal transduction cascades that give rise to these effects.
Collapse
Affiliation(s)
- J Mills
- Kinsmen Laboratory of Neurological Research, Graduate Program in Neuroscience, University of British Columbia, Vancouver, Canada
| | | |
Collapse
|
33
|
Kim SO, Irwin P, Katz S, Pelech SL. Expression of mitogen-activated protein kinase pathways during postnatal development of rat heart. J Cell Biochem 1998; 71:286-301. [PMID: 9779826 DOI: 10.1002/(sici)1097-4644(19981101)71:2<286::aid-jcb13>3.0.co;2-j] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The loss of ability to proliferate (terminal differentiation) and reduction in capability to resist ischemia are key phenomena observed during postnatal development of the heart. Mitogen-activated protein kinases (MAPKs) mediate signaling pathways for cell proliferation/differentiation and stress responses such as ischemia. In this study, the expression of these kinases and their associated kinases were investigated in rat heart ventricle. Extracts of 1-, 10-, 20-, 50-, and 365-day-old rat heart ventricles were probed with specific antibodies and their immunoreactivities were quantified by densitometry. Most of the mitogenic protein kinases including Raf1, RafB, Mek1, Erk2, and Rsk1 were significantly down-regulated, whereas the stress signaling kinases, such as Mlk3, Mekkl, Sekl, Mkk3, and Mapkapk2 were up-regulated in expression during postnatal development. Most MAP kinases including Erk1, JNKs, p38 Hog, as well as Rsk2, however, did not exhibit postnatal changes in expression. The proto-oncogene-encoded kinases Mos and Cot/Tpl 2 were up-regulated up to two- and four-fold, respectively, during development. Pakl, which may be involved in the regulation of cytoskeleton as well as in stress signaling, was downregulated with age, but the Pak2 isoform increased only after 50 days. All of these proteins, except RafB, were also detected in the isolated adult ventricular myocytes at comparable levels to those found in adult ventricle. Tissue distribution studies revealed that most of the protein kinases that were up-regulated during heart development tended to be preferentially expressed in heart, whereas the downregulated protein kinases were generally expressed in heart at relatively lesser amounts than in most of other tissues.
Collapse
Affiliation(s)
- S O Kim
- Faculty of Pharmaceutical Sciences, University of British Columbia, Vancouver, Canada
| | | | | | | |
Collapse
|
34
|
Abstract
The emergence of resistance in a tumor population is most often associated with a disregulation of gene expression, usually at the level of transcription. A major goal in the field of cancer chemotherapy is to define the mechanisms underlying transcriptional regulation of drug resistance genes in an effort to identify targets for therapeutic intervention. Recently, considerable progress has been made in identifying the molecular mechanisms involved in the transcriptional regulation of the P-glycoprotein (Pgp) gene. When overexpressed in tumor cells, Pgp confers resistance to a variety of chemotherapeutic agents; this resistance has been termed MDR (multidrug resistance). Moreover, Pgp is a normal component of a variety of highly differentiated cell types and, as such, is regulated by both internal and external environmental stimuli. In this review, we will discuss the current knowledge regarding the DNA elements and protein factors involved in both constitutive and inducible regulation of Pgp transcription in normal and tumor cells.
Collapse
Affiliation(s)
- K W Scotto
- Memorial Sloan-Kettering Cancer Center, Program in Molecular Pharmacology and Experimental Therapeutics, 1275 York Avenue, New York, NY, 10021, U.S.A.,
| | | |
Collapse
|
35
|
Mironov V, Van Montagu M, Inzé D. Regulation of cell division in plants: an Arabidopsis perspective. PROGRESS IN CELL CYCLE RESEARCH 1998; 3:29-41. [PMID: 9552404 DOI: 10.1007/978-1-4615-5371-7_3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Considerable progress has been achieved in the identification and molecular characterisation of genes and/or cDNAs coding for cyclin-dependent kinases (CDK) as well as cyclins in diverse plant species including Arabidopsis thaliana. Their transcriptional control during the cell cycle progression and the response to developmental cues and environmental signals has been studied in much detail, although the transcription factors mediating this regulation have yet to be identified. Experimental evidence has validated the involvement of CDKs and cyclins in cell division control in Arabidopsis and has revealed differential activation of two Arabidopsis CDKs in the course of the cell cycle. Finally, the first active CDK/cyclin pairs are being characterised, providing the basis for elucidation of their specific functions in cell cycle control and for unravelling the mechanisms that control their activity.
Collapse
Affiliation(s)
- V Mironov
- Department of Genetics, Flanders Interuniversity Institute for Biotechnology (VIB), Universiteit Gent, Belgium
| | | | | |
Collapse
|
36
|
Zafrullah M, Ozdener MH, Panda SK, Jameel S. The ORF3 protein of hepatitis E virus is a phosphoprotein that associates with the cytoskeleton. J Virol 1997; 71:9045-53. [PMID: 9371561 PMCID: PMC230205 DOI: 10.1128/jvi.71.12.9045-9053.1997] [Citation(s) in RCA: 197] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Hepatitis E virus (HEV) is a major human pathogen in the developing world. In the absence of an in vitro culture system, very little information exists on the basic biology of the virus. A small protein (approximately 13.5 kDa) of unknown function, pORF3, is encoded by the third open reading frame of HEV. We expressed pORF3 in transiently transfected COS-1 and Huh-7 cells and showed that it is a phosphoprotein which is modified at a serine residue(s). Deletion and site-directed mutants were created to establish Ser-80 as the phosphorylation site. This residue is present within a conserved primary sequence that showed consensus sites for phosphorylation by p34cdc2 kinase (cdc2K) and mitogen-activated protein kinase (MAPK). In vitro experiments with hexahistidine-tagged pORF3 expressed either in Escherichia coli or in COS-1 cells showed efficient phosphorylation with exogenously added MAPK. The pORF3 mutants also exhibited an in vitro phosphorylation profile with MAPK which was identical to that observed in vivo. In its primary sequence, pORF3 possesses two highly hydrophobic N-terminal domains. On subcellular fractionation, pORF3 was found to partition with the cytoskeletal fraction, and this association with the cytoskeleton was lost on deletion of hydrophobic domain I (amino acid residues 1 to 32). These results suggest that HEV pORF3 is a cytoskeleton-associated phosphoprotein and are discussed in terms of a possible function for pORF3 within the HEV replicative cycle.
Collapse
Affiliation(s)
- M Zafrullah
- Virology Group, International Centre for Genetic Engineering and Biotechnology, New Delhi, India
| | | | | | | |
Collapse
|
37
|
Wang J, Vantus T, Merlevede W, Vandenheede JR. Identification and characterization of an auto-activating MEK kinase from bovine brain: phosphorylation of serine-298 in the proline-rich domain of the mammalian MEKs. Int J Biochem Cell Biol 1997; 29:1071-83. [PMID: 9416003 DOI: 10.1016/s1357-2725(97)00054-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Mitogen-activated protein kinase kinases (MKKs or MEKs) are dual specificity tyrosine/threonine protein kinases that are activated by phosphorylation at two closely spaced serine residues (serines-218 and -222) by the c-mos and raf proto-oncogenes. This double phosphorylation is both necessary and sufficient for MEKs to activate the MAP kinase enzymes in vitro. The specificity or regulation of in vivo signaling to the mammalian MEKs (MEK1 and MEK2) was recently reported also to involve the differential phosphorylation of a proline-rich peptide located between the MEK kinase-subdomains IX and X. Here we report the purification and characterization of an auto-activating protein kinase from bovine brain that phosphorylates serine-298 of the MEK1 and MEK2 proline-rich insert peptides. The auto-activation of the MEK-S298 peptide kinase is the result of an intermolecular phosphorylation event that can be prevented by the peptide substrates. The inactive kinase migrates on gel filtration as a 90 kDa protein, and after activation as a 43 kDa phosphoprotein. Incorporation of 32P[phosphate] into 40-42 kDa proteins on SDS-PAGE parallels the activation of the enzyme, and dephosphorylation by protein phosphatase 2Ac reverses the activation. SDS-PAGE renaturation assays show that the 40 kDa protein has the capacity to autophosphorylate, and exhibits kinase activity towards myelin basic protein after activation. Phosphorylation of purified bovine brain MEK or recombinant MEK1 by the auto-activated kinase does not activate the enzyme, and does not interfere with the in vitro raf-mediated MEK activation. We conclude that still unknown kinases may control the MAP kinase pathway by targeting MEK.
Collapse
Affiliation(s)
- J Wang
- Afdeling Biochemie, Faculteit Geneeskunde, Katholieke Universiteit Leuven, Belgium
| | | | | | | |
Collapse
|