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Chikhale V, Goswami N, Khan MA, Borah P, Varma AK. Evaluation of Pathogenicity and Structural Alterations for the Mutations Identified in the Conserved Region of the C-Terminal Kinase Domain of Human-Ribosomal S6 Kinase 1. ACS OMEGA 2023; 8:16273-16283. [PMID: 37179615 PMCID: PMC10173430 DOI: 10.1021/acsomega.3c00722] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 03/23/2023] [Indexed: 05/15/2023]
Abstract
Human-ribosomal s6 kinase 1 (h-RSK1) is an effector kinase of the Ras/MAPK signaling pathway, which is involved in the regulation of the cell cycle, proliferation, and survival. RSKs comprise two functionally distinct kinase domains at the N-terminal (NTKD) and C-terminal (CTKD) separated by a linker region. The mutations in RSK1 may have the potential to provide an extra benefit to the cancer cell to proliferate, migrate, and survive. The present study focuses on evaluating the structural basis for the missense mutations identified at the C-terminal kinase domain of human-RSK1. A total of 139 mutations reported on RSK1 were retrieved from cBioPortal, where 62 were located at the CTKD region. Furthermore, 10 missense mutations Arg434Pro, Thr701Met, Ala704Thr, Arg725Trp, Arg726Gln, His533Asn, Pro613Leu, Ser720Cys, Arg725Gln, and Ser732Phe were predicted to be deleterious using in silico tools. To our observation, these mutations are located in the evolutionarily conserved region of RSK1 and shown to alter the inter- and intramolecular interactions and also the conformational stability of RSK1-CTKD. The molecular dynamics (MD) simulation study further revealed that the five mutations Arg434Pro, Thr701Met, Ala704Thr, Arg725Trp, and Arg726Gln showed maximum structural alterations in RSK1-CTKD. Thus, based on the in silico and MD simulation analysis, it can be concluded that the reported mutations may serve as potential candidates for further functional studies.
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Affiliation(s)
- Vaishnvee Chikhale
- Advanced
Centre for Treatment, Research and Education in Cancer, Navi Mumbai, Maharashtra 410210, India
- Training
School Complex, Homi Bhabha National Institute, Anushaktinagar, Mumbai, Maharashtra 400094, India
| | - Nabajyoti Goswami
- Advanced
Centre for Treatment, Research and Education in Cancer, Navi Mumbai, Maharashtra 410210, India
| | - Mudassar Ali Khan
- Advanced
Centre for Treatment, Research and Education in Cancer, Navi Mumbai, Maharashtra 410210, India
- Training
School Complex, Homi Bhabha National Institute, Anushaktinagar, Mumbai, Maharashtra 400094, India
| | - Probodh Borah
- Bioinformatics
Infrastructure Facility, Department of Animal Biotechnology, Assam Agricultural University, Khanapara, Guwahati, Assam 781022, India
| | - Ashok K. Varma
- Advanced
Centre for Treatment, Research and Education in Cancer, Navi Mumbai, Maharashtra 410210, India
- Training
School Complex, Homi Bhabha National Institute, Anushaktinagar, Mumbai, Maharashtra 400094, India
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Koutsougianni F, Alexopoulou D, Uvez A, Lamprianidou A, Sereti E, Tsimplouli C, Ilkay Armutak E, Dimas K. P90 ribosomal S6 kinases: A bona fide target for novel targeted anticancer therapies? Biochem Pharmacol 2023; 210:115488. [PMID: 36889445 DOI: 10.1016/j.bcp.2023.115488] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2022] [Revised: 02/28/2023] [Accepted: 03/01/2023] [Indexed: 03/08/2023]
Abstract
The 90 kDa ribosomal S6 kinase (RSK) family of proteins is a group of highly conserved Ser/Thr kinases. They are downstream effectors of the Ras/ERK/MAPK signaling cascade. ERK1/2 activation directly results in the phosphorylation of RSKs, which further, through interaction with a variety of different downstream substrates, activate various signaling events. In this context, they have been shown to mediate diverse cellular processes like cell survival, growth, proliferation, EMT, invasion, and metastasis. Interestingly, increased expression of RSKs has also been demonstrated in various cancers, such as breast, prostate, and lung cancer. This review aims to present the most recent advances in the field of RSK signaling that have occurred, such as biological insights, function, and mechanisms associated with carcinogenesis. We additionally present and discuss the recent advances but also the limitations in the development of pharmacological inhibitors of RSKs, in the context of the use of these kinases as putative, more efficient targets for novel anticancer therapeutic approaches.
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Affiliation(s)
- Fani Koutsougianni
- Department of Pharmacology, Faculty of Medicine, Health Sciences School, University of Thessaly, Larissa, Greece
| | - Dimitra Alexopoulou
- Department of Pharmacology, Faculty of Medicine, Health Sciences School, University of Thessaly, Larissa, Greece
| | - Ayca Uvez
- Department of Histology and Embryology, Faculty of Veterinary Medicine, Istanbul University-Cerrahpasa, 34500 Istanbul, Turkey
| | - Andromachi Lamprianidou
- Department of Pharmacology, Faculty of Medicine, Health Sciences School, University of Thessaly, Larissa, Greece
| | - Evangelia Sereti
- Dept of Translational Medicine, Medical Faculty, Lund University and Center for Molecular Pathology, Skäne University Hospital, Jan Waldenströms gata 59, SE 205 02 Malmö, Sweden
| | - Chrisiida Tsimplouli
- Department of Pharmacology, Faculty of Medicine, Health Sciences School, University of Thessaly, Larissa, Greece
| | - Elif Ilkay Armutak
- Department of Histology and Embryology, Faculty of Veterinary Medicine, Istanbul University-Cerrahpasa, 34500 Istanbul, Turkey
| | - Konstantinos Dimas
- Department of Pharmacology, Faculty of Medicine, Health Sciences School, University of Thessaly, Larissa, Greece.
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Müller L, Keil R, Hatzfeld M. Plakophilin 3 facilitates G1/S phase transition and enhances proliferation by capturing RB protein in the cytoplasm and promoting EGFR signaling. Cell Rep 2023; 42:112031. [PMID: 36689330 DOI: 10.1016/j.celrep.2023.112031] [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: 06/02/2022] [Revised: 10/26/2022] [Accepted: 01/10/2023] [Indexed: 01/23/2023] Open
Abstract
Plakophilin 3 (PKP3) is a component of desmosomes and is frequently overexpressed in cancer. Using keratinocytes either lacking or overexpressing PKP3, we identify a signaling axis from ERK to the retinoblastoma (RB) protein and the E2F1 transcription factor that is controlled by PKP3. RB and E2F1 are key components controlling G1/S transition in the cell cycle. We show that PKP3 stimulates the activity of ERK and its target RSK1. This inhibits expression of the transcription factor RUNX3, a positive regulator of the CDK inhibitor CDKN1A/p21, which is also downregulated by PKP3. Elevated CDKN1A prevents RB phosphorylation and E2F1 target gene expression, leading to delayed S phase entry and reduced proliferation in PKP3-depleted cells. Elevated PKP3 expression not only increases ERK activity but also captures phosphorylated RB (phospho-RB) in the cytoplasm to promote E2F1 activity and cell-cycle progression. These data identify a mechanism by which PKP3 promotes proliferation and acts as an oncogene.
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Affiliation(s)
- Lisa Müller
- Charles Tanford Protein Research Center, Martin Luther University Halle, Institute of Molecular Medicine, Department for Pathobiochemistry, Kurt-Mothes-Str. 3A, 06120 Halle, Germany.
| | - René Keil
- Charles Tanford Protein Research Center, Martin Luther University Halle, Institute of Molecular Medicine, Department for Pathobiochemistry, Kurt-Mothes-Str. 3A, 06120 Halle, Germany
| | - Mechthild Hatzfeld
- Charles Tanford Protein Research Center, Martin Luther University Halle, Institute of Molecular Medicine, Department for Pathobiochemistry, Kurt-Mothes-Str. 3A, 06120 Halle, Germany.
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4
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p90RSK Regulates p53 Pathway by MDM2 Phosphorylation in Thyroid Tumors. Cancers (Basel) 2022; 15:cancers15010121. [PMID: 36612117 PMCID: PMC9817759 DOI: 10.3390/cancers15010121] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/10/2022] [Accepted: 12/21/2022] [Indexed: 12/28/2022] Open
Abstract
The expression level of the tumor suppressor p53 is controlled by the E3 ubiquitin ligase MDM2 with a regulatory feedback loop, which allows p53 to upregulate its inhibitor MDM2. In this manuscript we demonstrated that p90RSK binds and phosphorylates MDM2 on serine 166 both in vitro and in vivo by kinase assay, immunoblot, and co-immunoprecipitation assay; this phosphorylation increases the stability of MDM2 which in turn binds p53, ubiquitinating it and promoting its degradation by proteasome. A pharmacological inhibitor of p90RSK, BI-D1870, decreases MDM2 phosphorylation, and restores p53 function, which in turn transcriptionally increases the expression of cell cycle inhibitor p21 and of pro-apoptotic protein Bax and downregulates the anti-apoptotic protein Bcl-2, causing a block of cell proliferation, measured by a BrdU assay and growth curve, and promoting apoptosis, measured by a TUNEL assay. Finally, an immunohistochemistry evaluation of primary thyroid tumors, in which p90RSK is very active, confirms MDM2 stabilization mediated by p90RSK phosphorylation.
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5
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Greenblatt MB, Shim JH, Bok S, Kim JM. The Extracellular Signal-Regulated Kinase Mitogen-Activated Protein Kinase Pathway in Osteoblasts. J Bone Metab 2022; 29:1-15. [PMID: 35325978 PMCID: PMC8948490 DOI: 10.11005/jbm.2022.29.1.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Accepted: 02/17/2022] [Indexed: 12/01/2022] Open
Abstract
Extracellular signal-regulated kinases (ERKs) are evolutionarily ancient signal transducers of the mitogen-activated protein kinase (MAPK) family that have long been linked to the regulation of osteoblast differentiation and bone formation. Here, we review the physiological functions, biochemistry, upstream activators, and downstream substrates of the ERK pathway. ERK is activated in skeletal progenitors and regulates osteoblast differentiation and skeletal mineralization, with ERK serving as a key regulator of Runt-related transcription factor 2, a critical transcription factor for osteoblast differentiation. However, new evidence highlights context-dependent changes in ERK MAPK pathway wiring and function, indicating a broader set of physiological roles associated with changes in ERK pathway components or substrates. Consistent with this importance, several human skeletal dysplasias are associated with dysregulation of the ERK MAPK pathway, including neurofibromatosis type 1 and Noonan syndrome. The continually broadening array of drugs targeting the ERK pathway for the treatment of cancer and other disorders makes it increasingly important to understand how interference with this pathway impacts bone metabolism, highlighting the importance of mouse studies to model the role of the ERK MAPK pathway in bone formation.
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Affiliation(s)
- Matthew B. Greenblatt
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical, New York, NY,
USA
- Research Division, Hospital for Special Surgery, New York, NY,
USA
| | - Jae-Hyuck Shim
- Division of Rheumatology, Department of Medicine, UMass Chan Medical School, Worcester, MA,
USA
- Horae Gene Therapy Center, and Li Weibo Institute for Rare Diseases Research, UMass Chan Medical School, Worcester, MA,
USA
| | - Seoyeon Bok
- Department of Pathology and Laboratory Medicine, Weill Cornell Medical, New York, NY,
USA
| | - Jung-Min Kim
- Division of Rheumatology, Department of Medicine, UMass Chan Medical School, Worcester, MA,
USA
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Liu Z, Liu C, Wang X, Li W, Zhou J, Dong P, Xiao MZX, Wang C, Zhang Y, Fu J, Zhu F, Liang Q. RSK1 SUMOylation is required for KSHV lytic replication. PLoS Pathog 2021; 17:e1010123. [PMID: 34871326 PMCID: PMC8675914 DOI: 10.1371/journal.ppat.1010123] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/16/2021] [Accepted: 11/16/2021] [Indexed: 01/01/2023] Open
Abstract
RSK1, a downstream kinase of the MAPK pathway, has been shown to regulate multiple cellular processes and is essential for lytic replication of a variety of viruses, including Kaposi's sarcoma-associated herpesvirus (KSHV). Besides phosphorylation, it is not known whether other post-translational modifications play an important role in regulating RSK1 function. We demonstrate that RSK1 undergoes robust SUMOylation during KSHV lytic replication at lysine residues K110, K335, and K421. SUMO modification does not alter RSK1 activation and kinase activity upon KSHV ORF45 co-expression, but affects RSK1 downstream substrate phosphorylation. Compared to wild-type RSK1, the overall phosphorylation level of RxRxxS*/T* motif is significantly declined in RSK1K110/335/421R expressing cells. Specifically, SUMOylation deficient RSK1 cannot efficiently phosphorylate eIF4B. Sequence analysis showed that eIF4B has one SUMO-interacting motif (SIM) between the amino acid position 166 and 170 (166IRVDV170), which mediates the association between eIF4B and RSK1 through SUMO-SIM interaction. These results indicate that SUMOylation regulates the phosphorylation of RSK1 downstream substrates, which is required for efficient KSHV lytic replication.
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Affiliation(s)
- Zhenshan Liu
- Research Center of Translational Medicine, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chengrong Liu
- Research Center of Translational Medicine, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Xin Wang
- Research Center of Translational Medicine, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Wenwei Li
- Department of Biological Science, Florida State University, Tallahassee, Flordia, United States of America
| | - Jingfan Zhou
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Peixian Dong
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Maggie Z. X. Xiao
- Faculty of Medicine, University of Alberta, Edmonton, Alberta, Canada
| | - Chunxia Wang
- Department of Critical Care Medicine, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Yucai Zhang
- Department of Critical Care Medicine, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
| | - Joyce Fu
- Department of Statistics, University of California, Riverside, Riverside, California, United States of America
| | - Fanxiu Zhu
- Department of Biological Science, Florida State University, Tallahassee, Flordia, United States of America
- * E-mail: (FZ); (QL)
| | - Qiming Liang
- Research Center of Translational Medicine, Shanghai Children’s Hospital, Shanghai Jiao Tong University, Shanghai, China
- Shanghai Institute of Immunology, Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
- * E-mail: (FZ); (QL)
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8
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Lee CJ, Lee GE, An HJ, Cho ES, Chen W, Lee JY, Kang HC, Lee HS, Cho YY. F-box Protein βTrCP1 Is a Substrate of Extracellular Signal-regulated Kinase 2. J Cancer Prev 2021; 26:174-182. [PMID: 34703820 PMCID: PMC8511579 DOI: 10.15430/jcp.2021.26.3.174] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Revised: 09/10/2021] [Accepted: 09/13/2021] [Indexed: 11/28/2022] Open
Abstract
F-box proteins, consisting of 69 members which are organized into the three subclasses FBXW, FBXL, and FBXO, are the substrate specific recognition subunits of the SKP1-Cullin 1-F-box protein E3 ligase complex. Although βTrCP 1 and 2, members of the FBXW subfamily, are known to regulate some protein stability, molecular mechanisms by which these proteins can recognize proper substrates are unknown. In this study, it was found that βTrCP1 showed strong interaction with members of mitogen-activated protein kinases. Although extracellular signal-regulated kinase (ERK) 3, p38β, and p38δ showed weak interactions, ERK2 specifically interacted with βTrCP1 as assessed by immunoprecipitation. In interaction domain determination experiments, we found that ERK2 interacted with two independent ERK docking sites located in the F-box domain and linker domain, but not the WD40 domain, of βTrCP1. Notably, mutations of βTrCP1 at the ERK docking sites abolished the interaction with ERK2. βTrCP1 underwent phosphorylation by EGF stimulation, while the presence of the mitogen-activated protein kinase kinases inhibitor U0126, genetic silencing by sh-ERK2, and mutation of the ERK docking site of βTrCP1 inhibited phosphorylation. This inhibition of βTrCP1 phosphorylation resulted in a shortened half-life and low protein levels. These results suggest that ERK2-mediated βTrCP1 phosphorylation may induce the destabilization of βTrCP1.
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Affiliation(s)
- Cheol-Jung Lee
- BRL & BK21-4th Team, College of Pharmacy, The Catholic University of Korea, Bucheon, Korea.,Research Center for Materials Analysis, Korea Basic Science Institute, Daejeon, Korea
| | - Ga-Eun Lee
- BRL & BK21-4th Team, College of Pharmacy, The Catholic University of Korea, Bucheon, Korea
| | - Hyun-Jung An
- BRL & BK21-4th Team, College of Pharmacy, The Catholic University of Korea, Bucheon, Korea
| | - Eun Suh Cho
- Department of Biochemistry, College of Biological Sciences, University of Minnesota, Minneapolis, MN, USA
| | - Weidong Chen
- BRL & BK21-4th Team, College of Pharmacy, The Catholic University of Korea, Bucheon, Korea
| | - Joo Young Lee
- BRL & BK21-4th Team, College of Pharmacy, The Catholic University of Korea, Bucheon, Korea
| | - Han Chang Kang
- BRL & BK21-4th Team, College of Pharmacy, The Catholic University of Korea, Bucheon, Korea
| | - Hye Suk Lee
- BRL & BK21-4th Team, College of Pharmacy, The Catholic University of Korea, Bucheon, Korea
| | - Yong-Yeon Cho
- BRL & BK21-4th Team, College of Pharmacy, The Catholic University of Korea, Bucheon, Korea
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9
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RSK Isoforms in Acute Myeloid Leukemia. Biomedicines 2021; 9:biomedicines9070726. [PMID: 34202904 PMCID: PMC8301392 DOI: 10.3390/biomedicines9070726] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/20/2021] [Accepted: 06/22/2021] [Indexed: 12/21/2022] Open
Abstract
Ribosomal S6 Kinases (RSKs) are a group of serine/threonine kinases that function downstream of the Ras/Raf/MEK/ERK signaling pathway. Four RSK isoforms are directly activated by ERK1/2 in response to extracellular stimuli including growth factors, hormones, and chemokines. RSKs phosphorylate many cytosolic and nuclear targets resulting in the regulation of diverse cellular processes such as cell proliferation, survival, and motility. In hematological malignancies such as acute myeloid leukemia (AML), RSK isoforms are highly expressed and aberrantly activated resulting in poor outcomes and resistance to chemotherapy. Therefore, understanding RSK function in leukemia could lead to promising therapeutic strategies. This review summarizes the current information on human RSK isoforms and discusses their potential roles in the pathogenesis of AML and mechanism of pharmacological inhibitors.
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Xu J, Jia Q, Zhang Y, Yuan Y, Xu T, Yu K, Chai J, Wang K, Chen L, Xiao T, Li M. Prominent roles of ribosomal S6 kinase 4 (RSK4) in cancer. Pathol Res Pract 2021; 219:153374. [PMID: 33621918 DOI: 10.1016/j.prp.2021.153374] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 02/05/2021] [Accepted: 02/08/2021] [Indexed: 11/19/2022]
Abstract
RSK4 refers to one Ser/Thr protein kinase functioning downstream pertaining to the signaling channel of protein kinase (MAPK) stimulated by Ras/mitogen. RSK4 can regulate numerous substrates impacting cells' surviving state, growing processes and proliferating process. Thus, dysregulated RSK4 active state display a relationship to several carcinoma categories, covering breast carcinoma, esophageal squamous cell carcinoma, glioma, colorectal carcinoma, lung carcinoma, ovarian carcinoma, leukemia, endometrial carcinoma, and kidney carcinoma. Whether RSK4 is a tumor suppressor gene or one oncogene remains controversial. No specific inhibiting elements for RSK4 have been found. This review briefs the existing information regarding RSK4 activating process, the function and mechanism of RSK4 in different tumors, and the research progress and limitations of existing RSK inhibitors. RSK4 may be a potential target of molecular therapy medicine in the future.
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Affiliation(s)
- Junpeng Xu
- State Key Laboratory of Cancer Biology, Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Qingge Jia
- Xi'an International Medical Center, Northwest University, Xi'an, China
| | - Yan Zhang
- Children's Heart Disease Center, Sichuan Maternal and Child Health Hospital, Chengdu, China
| | - Yuan Yuan
- State Key Laboratory of Cancer Biology, Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Tianqi Xu
- State Key Laboratory of Cancer Biology, Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Kangjie Yu
- State Key Laboratory of Cancer Biology, Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Jia Chai
- State Key Laboratory of Cancer Biology, Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Kaijing Wang
- State Key Laboratory of Cancer Biology, Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | - Ligang Chen
- Department of Neurology, General Hospital of Northern Theater Command, Shenyang, China.
| | - Tian Xiao
- State Key Laboratory of Cancer Biology, Department of Biochemistry and Molecular Biology, School of Basic Medicine, Fourth Military Medical University, Xi'an, China.
| | - Mingyang Li
- State Key Laboratory of Cancer Biology, Department of Pathology, Xijing Hospital, Fourth Military Medical University, Xi'an, China.
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Chan LK, Ho DWH, Kam CS, Chiu EYT, Lo ILO, Yau DTW, Cheung ETY, Tang CN, Tang VWL, Lee TKW, Wong CCL, Chok KSH, Chan ACY, Cheung TT, Wong CM, Ng IOL. RSK2-inactivating mutations potentiate MAPK signaling and support cholesterol metabolism in hepatocellular carcinoma. J Hepatol 2021; 74:360-371. [PMID: 32918955 DOI: 10.1016/j.jhep.2020.08.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Revised: 08/05/2020] [Accepted: 08/25/2020] [Indexed: 12/28/2022]
Abstract
BACKGROUND & AIMS Mutational profiling of patient tumors has suggested that hepatocellular carcinoma (HCC) development is mainly driven by loss-of-function mutations in tumor suppressor genes. p90 ribosomal S6 kinase 2 (RSK2) functions as a direct downstream kinase of ERK1/2 and elevated RSK2 expression has been reported to support oncogenic functions in some cancers. We investigated if RSK2 was also dysregulated by inactivating mutations in cancers including HCC. METHODS We performed exome sequencing and targeted DNA sequencing on HBV-associated HCCs to examine recurrent RSK2 mutations. The functional significance and mechanistic consequences of RSK2 mutations were examined in natural RSK2-null HCC cells, and RSK2-knockout HCC cells. The potential downstream pathways underlying RSK2 mutations were investigated by RNA sequencing, qRT-PCR and mass spectrometry. RESULTS We detected recurrent somatic RSK2 mutations at a rate of 6.3% in our HCC cohorts and revealed that, among many cancer types, HCC was the cancer most commonly harboring RSK2 mutations. The RSK2 mutations were inactivating and associated with a more aggressive tumor phenotype. We found that, functionally, restoring RSK2 expression in natural RSK2-null HBV-positive Hep3B cells suppressed proliferation and migration in vitro and tumorigenicity in vivo. Mechanistically, RSK2-inactivating mutations attenuated a SOS1/2-dependent negative feedback loop, leading to the activation of MAPK signaling. Of note, this RSK2 mutation-mediated MAPK upregulation rendered HCC cells more sensitive to sorafenib, a first-line multi-kinase inhibitor for advanced HCC. Furthermore, such activation of MAPK signaling enhanced cholesterol biosynthesis-related gene expression in HCC cells. CONCLUSIONS Our findings reveal the mechanistic and functional significance of RSK2-inactivating mutations in HCC. These inactivating mutations may serve as an alternative route to activate MAPK signaling and cholesterol metabolism in HCC. LAY SUMMARY In this study, we identified and functionally characterized RSK2-inactivating mutations in human hepatocellular carcinoma and demonstrated their association with aggressive tumor behavior. Mutations in RSK2 drive signaling pathways with known oncogenic potential, leading to enhanced cholesterol biosynthesis and potentially sensitizing tumors to sorafenib treatment.
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Affiliation(s)
- Lo-Kong Chan
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong.
| | - Daniel Wai-Hung Ho
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Charles Shing Kam
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Elley Yung-Tuen Chiu
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | | | | | | | - Chung-Ngai Tang
- Department of Surgery, Pamela Youde Nethersole Eastern Hospital, Hong Kong
| | - Victor Wai-Lun Tang
- Department of Pathology, Pamela Youde Nethersole Eastern Hospital, Hong Kong
| | - Terence Kin-Wah Lee
- Department of Applied Biology and Chemical Technology, The Hong Kong Polytechnic University, Hong Kong
| | - Carmen Chak-Lui Wong
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Kenneth Siu-Ho Chok
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong; Department of Surgery, The University of Hong Kong, Hong Kong
| | - Albert Chi-Yan Chan
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong; Department of Surgery, The University of Hong Kong, Hong Kong
| | - Tan-To Cheung
- State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong; Department of Surgery, The University of Hong Kong, Hong Kong
| | - Chun-Ming Wong
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong
| | - Irene Oi-Lin Ng
- Department of Pathology, The University of Hong Kong, Hong Kong; State Key Laboratory of Liver Research, The University of Hong Kong, Hong Kong.
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12
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Yang ZH, Wu XN, He P, Wang X, Wu J, Ai T, Zhong CQ, Wu X, Cong Y, Zhu R, Li H, Cai ZY, Mo W, Han J. A Non-canonical PDK1-RSK Signal Diminishes Pro-caspase-8-Mediated Necroptosis Blockade. Mol Cell 2020; 80:296-310.e6. [PMID: 32979304 DOI: 10.1016/j.molcel.2020.09.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 08/17/2020] [Accepted: 09/03/2020] [Indexed: 01/14/2023]
Abstract
Necroptosis induction in vitro often requires caspase-8 (Casp8) inhibition by zVAD because pro-Casp8 cleaves RIP1 to disintegrate the necrosome. It has been unclear how the Casp8 blockade of necroptosis is eliminated naturally. Here, we show that pro-Casp8 within the necrosome can be inactivated by phosphorylation at Thr265 (pC8T265). pC8T265 occurs in vitro in various necroptotic cells and in the cecum of TNF-treated mice. p90 RSK is the kinase of pro-Casp8. It is activated by a mechanism that does not need ERK but PDK1, which is recruited to the RIP1-RIP3-MLKL-containing necrosome. Phosphorylation of pro-Casp8 at Thr265 can substitute for zVAD to permit necroptosis in vitro. pC8T265 mimic T265E knockin mice are embryonic lethal due to unconstrained necroptosis, and the pharmaceutical inhibition of RSK-mediated pC8T265 diminishes TNF-induced cecum damage and lethality in mice by halting necroptosis. Thus, phosphorylation of pro-Casp8 at Thr265 by RSK is an intrinsic mechanism for passing the Casp8 checkpoint of necroptosis.
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Affiliation(s)
- Zhang-Hua Yang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xiao-Nan Wu
- School of Pharmaceutical Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Peng He
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xuekun Wang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Jianfeng Wu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Tingting Ai
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Chuan-Qi Zhong
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Xiurong Wu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Yu Cong
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Rongfeng Zhu
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Hongda Li
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Zhi-Yu Cai
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China
| | - Wei Mo
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China; Research Unit of Cellular Stress of CAMS, Cancer Research Center of Xiamen University, Xiang'an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China.
| | - Jiahuai Han
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, School of Life Sciences, Xiamen University, Xiamen, Fujian 361102, China; Research Unit of Cellular Stress of CAMS, Cancer Research Center of Xiamen University, Xiang'an Hospital of Xiamen University, School of Medicine, Xiamen University, Xiamen, Fujian 361102, China.
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13
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Sami A, Selzer ME, Li S. Advances in the Signaling Pathways Downstream of Glial-Scar Axon Growth Inhibitors. Front Cell Neurosci 2020; 14:174. [PMID: 32714150 PMCID: PMC7346763 DOI: 10.3389/fncel.2020.00174] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2020] [Accepted: 05/22/2020] [Indexed: 12/15/2022] Open
Abstract
Axon growth inhibitors generated by reactive glial scars play an important role in failure of axon regeneration after CNS injury in mature mammals. Among the inhibitory factors, chondroitin sulfate proteoglycans (CSPGs) are potent suppressors of axon regeneration and are important molecular targets for designing effective therapies for traumatic brain injury or spinal cord injury (SCI). CSPGs bind with high affinity to several transmembrane receptors, including two members of the leukocyte common antigen related (LAR) subfamily of receptor protein tyrosine phosphatases (RPTPs). Recent studies demonstrate that multiple intracellular signaling pathways downstream of these two RPTPs mediate the growth-inhibitory actions of CSPGs. A better understanding of these signaling pathways may facilitate development of new and effective therapies for CNS disorders characterized by axonal disconnections. This review will focus on recent advances in the downstream signaling pathways of scar-mediated inhibition and their potential as the molecular targets for CNS repair.
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Affiliation(s)
- Armin Sami
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States.,Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Michael E Selzer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States.,Department of Neurology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
| | - Shuxin Li
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States.,Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA, United States
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14
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Chou PC, Rajput S, Zhao X, Patel C, Albaciete D, Oh WJ, Daguplo HQ, Patel N, Su B, Werlen G, Jacinto E. mTORC2 Is Involved in the Induction of RSK Phosphorylation by Serum or Nutrient Starvation. Cells 2020; 9:E1567. [PMID: 32605013 PMCID: PMC7408474 DOI: 10.3390/cells9071567] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2020] [Revised: 06/17/2020] [Accepted: 06/23/2020] [Indexed: 12/26/2022] Open
Abstract
Cells adjust to nutrient fluctuations to restore metabolic homeostasis. The mechanistic target of rapamycin (mTOR) complex 2 responds to nutrient levels and growth signals to phosphorylate protein kinases belonging to the AGC (Protein Kinases A,G,C) family such as Akt and PKC. Phosphorylation of these AGC kinases at their conserved hydrophobic motif (HM) site by mTORC2 enhances their activation and mediates the functions of mTORC2 in cell growth and metabolism. Another AGC kinase family member that is known to undergo increased phosphorylation at the homologous HM site (Ser380) is the p90 ribosomal S6 kinase (RSK). Phosphorylation at Ser380 is facilitated by the activation of the mitogen-activated protein kinase/extracellular signal regulated kinase (MAPK/ERK) in response to growth factor stimulation. Here, we demonstrate that optimal phosphorylation of RSK at this site requires an intact mTORC2. We also found that RSK is robustly phosphorylated at Ser380 upon nutrient withdrawal or inhibition of glycolysis, conditions that increase mTORC2 activation. However, pharmacological inhibition of mTOR did not abolish RSK phosphorylation at Ser380, indicating that mTOR catalytic activity is not required for this phosphorylation. Since RSK and SIN1β colocalize at the membrane during serum restimulation and acute glutamine withdrawal, mTORC2 could act as a scaffold to enhance RSK HM site phosphorylation. Among the known RSK substrates, the CCTβ subunit of the chaperonin containing TCP-1 (CCT) complex had defective phosphorylation in the absence of mTORC2. Our findings indicate that the mTORC2-mediated phosphorylation of the RSK HM site could confer RSK substrate specificity and reveal that RSK responds to nutrient fluctuations.
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Affiliation(s)
- Po-Chien Chou
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Swati Rajput
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Xiaoyun Zhao
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China; (X.Z.); (B.S.)
| | - Chadni Patel
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Danielle Albaciete
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Won Jun Oh
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Heineken Queen Daguplo
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Nikhil Patel
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Bing Su
- Department of Immunology and Microbiology, Shanghai Jiao Tong University School of Medicine, Shanghai 200240, China; (X.Z.); (B.S.)
| | - Guy Werlen
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
| | - Estela Jacinto
- Department of Biochemistry and Molecular Biology, Rutgers-Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA; (P.-C.C.); (S.R.); (C.P.); (D.A.); (W.J.O.); (H.Q.D.); (N.P.); (G.W.)
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15
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Invergo BM, Petursson B, Akhtar N, Bradley D, Giudice G, Hijazi M, Cutillas P, Petsalaki E, Beltrao P. Prediction of Signed Protein Kinase Regulatory Circuits. Cell Syst 2020; 10:384-396.e9. [DOI: 10.1016/j.cels.2020.04.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 01/24/2020] [Accepted: 04/20/2020] [Indexed: 01/18/2023]
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16
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Weng P, Wu L, Jiang Z, Ran X, Xu K, Xie X, Xu X, Chen X, Han K, Mao H, Hu C. Grass carp (Ctenopharyngodon idella) RSK2 protects cells anti-apoptosis by up-regulating BCL-2. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2019; 97:45-56. [PMID: 30905684 DOI: 10.1016/j.dci.2019.03.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2018] [Revised: 03/13/2019] [Accepted: 03/18/2019] [Indexed: 06/09/2023]
Abstract
In mammals, toll-like receptor 3 (TLR3) is capable of recognizing double-stranded RNA and then initiates transcription of IFN-β. TLR3 can activate the innate immune system by phosphorylating extracellular signal-regulated kinase 1 (ERK1) in the mitogen-activated protein kinase (MAPK) pathway. As a downstream signaling protein of ERK1, ribosomal protein S6 kinase alpha 3 (RSK2) is activated through the "classical" MAPK pathway. So RSK2 plays a critical role in response to innate immune system induced by TRL3. However, the innate immune mechanism of RSK2 remains indistinct in fish. In this study, we cloned and characterized a full length cDNA sequence of RSK2 from Ctenopharyngodon idella (named CiRSK2, MH844551). The full length cDNA of CiRSK2 is 3930 bp with a coding sequence of 2202 bp encoding a polypeptide of 734 amino acids. The expression of CiRSK2 was ubiquitous and significantly up-regulated under the stimulation of poly (I:C) in eight different tissues of C. idella and C. idella kidney cells (CIK). In addition, poly (I:C) stimulation also up-regulated the expression of CiERK1 mRNA in CIK cells and the phosphorylation of CiERK1. We also demonstrated that the activated CiERK1 interacted with CiRSK2 by CO-IP assay and immunofluorescence assay. To further investigate the relationship between CiRSK2 and CiERK1, we performed subcellular localization of CiRSK2 at different periods of CiERK1 stimulation. The result showed that CiERK1 can make CiRSK2 enter the nucleus. Subsequently, we found that CiRSK2 increased the transcriptional level of CiBCL-2 and protein level of CiBCL-2 significantly. Then cell apoptosis was inhibited to a certain extent. Overall, our results suggested that CiRSK2 plays important roles in fish innate immunity and is able to inhibit cell apoptosis by up-regulating CiBCL-2.
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Affiliation(s)
- Panwei Weng
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China
| | - Liping Wu
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China
| | - Zeyin Jiang
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China
| | - Xiaoqin Ran
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China
| | - Kang Xu
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China
| | - Xiaofen Xie
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China
| | - Xiaowen Xu
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China
| | - Xingxing Chen
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China
| | - Kun Han
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China
| | - Huiling Mao
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China.
| | - Chengyu Hu
- College of Life Science, Nanchang University, Poyang Lake Key Laboratory of Environment and Resource Utilization, Ministry of Education, Nanchang University, Nanchang, 330031, China.
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17
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RSK2-Mediated ELK3 Activation Enhances Cell Transformation and Breast Cancer Cell Growth by Regulation of c-fos Promoter Activity. Int J Mol Sci 2019; 20:ijms20081994. [PMID: 31018569 PMCID: PMC6515335 DOI: 10.3390/ijms20081994] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Revised: 04/17/2019] [Accepted: 04/19/2019] [Indexed: 12/14/2022] Open
Abstract
Ribosomal S6 kinase 2 (RSK2), regulated by Ras/Raf/MEKs/ERKs, transmits upstream activation signals to downstream substrates including kinases and transcription and epigenetic factors. We observed that ELK members, including ELK1, 3, and 4, highly interacted with RSK2. We further observed that the RSK2-ELK3 interaction was mediated by N-terminal kinase and linker domains of RSK2, and the D and C domains of ELK3, resulting in the phosphorylation of ELK3. Importantly, RSK2-mediated ELK3 enhanced c-fos promoter activity. Notably, chemical inhibition of RSK2 signaling using kaempferol (a RSK2 inhibitor) or U0126 (a selective MEK inhibitor) suppressed EGF-induced c-fos promoter activity. Moreover, functional deletion of RSK2 by knockdown or knockout showed that RSK2 deficiency suppressed EGF-induced c-fos promoter activity, resulting in inhibition of AP-1 transactivation activity and Ras-mediated foci formation in NIH3T3 cells. Immunocytofluorescence assay demonstrated that RSK2 deficiency reduced ELK3 localization in the nucleus. In MDA-MB-231 breast cancer cells, knockdown of RSK2 or ELK3 suppressed cell proliferation with accumulation at the G1 cell cycle phase, resulting in inhibition of foci formation and anchorage-independent cancer colony growth in soft agar. Taken together, these results indicate that a novel RSK2/ELK3 signaling axis, by enhancing c-Fos-mediated AP-1 transactivation activity, has an essential role in cancer cell proliferation and colony growth.
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18
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Koizumi Y, Nagai K, Gao L, Koyota S, Yamaguchi T, Natsui M, Imai Y, Hasumi K, Sugiyama T, Kuba K. Involvement of RSK1 activation in malformin-enhanced cellular fibrinolytic activity. Sci Rep 2018; 8:5472. [PMID: 29615689 PMCID: PMC5882963 DOI: 10.1038/s41598-018-23745-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2017] [Accepted: 03/15/2018] [Indexed: 12/03/2022] Open
Abstract
Pharmacological interventions to enhance fibrinolysis are effective for treating thrombotic disorders. Utilizing the in vitro U937 cell line-based fibrin degradation assay, we had previously found a cyclic pentapeptide malformin A1 (MA1) as a novel activating compound for cellular fibrinolytic activity. The mechanism by which MA1 enhances cellular fibrinolytic activity remains unknown. In the present study, we show that RSK1 is a crucial mediator of MA1-induced cellular fibrinolysis. Treatment with rhodamine-conjugated MA1 showed that MA1 localizes mainly in the cytoplasm of U937 cells. Screening with an antibody macroarray revealed that MA1 induces the phosphorylation of RSK1 at Ser380 in U937 cells. SL0101, an inhibitor of RSK, inhibited MA1-induced fibrinolytic activity, and CRISPR/Cas9-mediated knockout of RSK1 but not RSK2 suppressed MA1-enhanced fibrinolysis in U937 cells. Synthetic active MA1 derivatives also induced the phosphorylation of RSK1. Furthermore, MA1 treatment stimulated phosphorylation of ERK1/2 and MEK1/2. PD98059, an inhibitor of MEK1/2, inhibited MA1-induced phosphorylation of RSK1 and ERK1/2, indicating that MA1 induces the activation of the MEK-ERK-RSK pathway. Moreover, MA1 upregulated the expression of urokinase-type plasminogen activator (uPA) and increased uPA secretion. These inductions were abrogated in RSK1 knockout cells. These results indicate that RSK1 is a key regulator of MA1-induced extracellular fibrinolytic activity.
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Affiliation(s)
- Yukio Koizumi
- Department of Biochemistry and Metabolic Science, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543, Japan.
| | - Kenichiro Nagai
- School of Pharmacy, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo, 108-8641, Japan
| | - Lina Gao
- Department of Biochemistry and Metabolic Science, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543, Japan
| | - Souichi Koyota
- Molecular Medicine Laboratory, Bioscience Education and Research Support Center, Akita University, 1-1-1 Hondo, Akita, 010-8543, Japan
| | - Tomokazu Yamaguchi
- Department of Biochemistry and Metabolic Science, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543, Japan
| | - Miyuki Natsui
- Department of Biochemistry and Metabolic Science, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543, Japan
| | - Yumiko Imai
- Laboratory of Regulation of Intractable Infectious Diseases, National Institute of Biomedical Innovation, Health and Nutrition, 7-6-8 Saito-Asagi, Ibaraki, Osaka, 567-0085, Japan
| | - Keiji Hasumi
- Department of Applied Biological Science, Tokyo Noko University, 3-5-8 Saiwaicho, Fuchu, Tokyo, 183-8509, Japan
| | - Toshihiro Sugiyama
- Department of Biochemistry and Metabolic Science, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543, Japan
| | - Keiji Kuba
- Department of Biochemistry and Metabolic Science, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita, 010-8543, Japan
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19
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RSK2 activity mediates glioblastoma invasiveness and is a potential target for new therapeutics. Oncotarget 2018; 7:79869-79884. [PMID: 27829215 PMCID: PMC5346757 DOI: 10.18632/oncotarget.13084] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 10/21/2016] [Indexed: 01/06/2023] Open
Abstract
In glioblastoma (GBM), infiltration of primary tumor cells into the normal tissue and dispersal throughout the brain is a central challenge to successful treatment that remains unmet. Indeed, patients respond poorly to the current therapies of tumor resection followed by chemotherapy with radiotherapy and have only a 16-month median survival. It is therefore imperative to develop novel therapies. RSK2 is a kinase that regulates proliferation and adhesion and can promote metastasis. We demonstrate that active RSK2 regulates GBM cell adhesion and is essential for cell motility and invasion of patient-derived GBM neurospheres. RSK2 control of adhesion and migration is mediated in part by its effects on integrin-Filamin A complexes. Importantly, inhibition of RSK2 by either RSK inhibitors or shRNA silencing impairs invasion and combining RSK2 inhibitors with temozolomide improves efficacy in vitro. In agreement with the in vitro data, using public datasets, we find that RSK2 is significantly upregulated in vivo in human GBM patient tumors, and that high RSK2 expression significantly correlates with advanced tumor stage and poor patient survival. Together, our data provide strong evidence that RSK inhibitors could enhance the effectiveness of existing GBM treatment, and support RSK2 targeting as a promising approach for novel GBM therapy.
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RSK2 drives cell motility by serine phosphorylation of LARG and activation of Rho GTPases. Proc Natl Acad Sci U S A 2017; 115:E190-E199. [PMID: 29279389 PMCID: PMC5777029 DOI: 10.1073/pnas.1708584115] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cell motility is a dynamic process that requires the directed application of force and continuous coordinated changes in cell adhesion and cytoskeletal architecture often in response to extracellular stimuli. Here we have defined a mechanism by which RSK2 can promote cell migration and invasion in response to promotility stimuli. We show that in response to these signals RSK2 directly binds the RhoGEF LARG and phosphorylates it, thereby promoting LARG activation of RhoA GTPases. Moreover, we find that RSK2 is important for epidermal growth factor activation of Rho GTPases. These results advance our understanding of cell motility, RSK kinase function, and LARG/RhoA activation by revealing that these pathways are integrated and the precise mechanism by which that is accomplished. Directed migration is essential for cell motility in many processes, including development and cancer cell invasion. RSKs (p90 ribosomal S6 kinases) have emerged as central regulators of cell migration; however, the mechanisms mediating RSK-dependent motility remain incompletely understood. We have identified a unique signaling mechanism by which RSK2 promotes cell motility through leukemia-associated RhoGEF (LARG)-dependent Rho GTPase activation. RSK2 directly interacts with LARG and nucleotide-bound Rho isoforms, but not Rac1 or Cdc42. We further show that epidermal growth factor or FBS stimulation induces association of endogenous RSK2 with LARG and LARG with RhoA. In response to these stimuli, RSK2 phosphorylates LARG at Ser1288 and thereby activates RhoA. Phosphorylation of RSK2 at threonine 577 is essential for activation of LARG-RhoA. Moreover, RSK2-mediated motility signaling depends on RhoA and -B, but not RhoC. These results establish a unique RSK2-dependent LARG-RhoA signaling module as a central organizer of directed cell migration and invasion.
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21
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Rasmussen MK, Nielsen J, Kjellerup RB, Andersen SM, Rittig AH, Johansen C, Iversen L, Gesser B. Protein phosphatase 2Cδ/Wip1 regulates phospho-p90RSK2 activity in lesional psoriatic skin. J Inflamm Res 2017; 10:169-180. [PMID: 29290690 PMCID: PMC5735993 DOI: 10.2147/jir.s152869] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Objectives P90 ribosomal S6 kinase (RSK) 1 and 2 are serine/threonine protein kinases believed to mediate proliferation and apoptosis via the extracellular signal-regulated kinases (ERK1/2) signaling pathway. Macrophage migration inhibitory factor (MIF) and epidermal growth factor (EGF) are activators of this pathway and are elevated in the serum of patients with psoriasis compared with healthy controls. Studies on COS-7 cell cultures have shown that protein phosphatase 2Cδ (PP2Cδ) decreases the activity of RSK2 following EGF stimulation. We therefore hypothesize that PP2Cδ regulates RSK2 activity in psoriasis. Methods In paired biopsies from nonlesional (NL) and lesional (L) skins, we analyzed the level of RSK1, 2 phosphorylation and the expression of PP2Cδ isoforms, integrin-linked kinase-associated serine/threonine phosphatase (ILKAP) and wild-type p53-induced phosphatase 1 (Wip1) by Western blotting, immunofluorescence and coimmunoprecipitation with monoclonal antibody for RSK2. The induction of Wip1 by MIF or EGF was studied in cultured normal human keratinocytes. Results The protein level of RSK1, 2 phosphorylated at T573/T577 was significantly increased in L compared with NL psoriatic skin, while phosphorylation at S380/S386 was reduced in L compared with NL psoriatic skin when assayed by Western blotting and immunofluorescence microscopy. ILKAP expression was significantly higher in L than in NL skin, whereas Wip1 was expressed in similar amounts but showed increased coimmunoprecipitation with RSK2 in L compared with NL psoriatic skin. In cultured normal human keratinocytes stimulated with MIF, Wip1 phosphorylation and Wip1 expression were increased after 24 hours, but not when costimulated with dimethyl fumarate (DMF). The increased coimmunoprecipitation of Wip1 with RSK2 was significantly induced by EGF or MIF activation at 24 hours and could be significantly inhibited by DMF or the ERK1/2 inhibitor PD98059. Conclusion The complex formation of Wip1 with RSK2 indicates a direct interaction reducing P-RSK2 (S386) activation in L skin and indicates that Wip1 has a role in the pathogenesis of psoriasis.
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Affiliation(s)
- Mads K Rasmussen
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Jakob Nielsen
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | | | - Stine M Andersen
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Anne H Rittig
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Claus Johansen
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Lars Iversen
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
| | - Borbala Gesser
- Department of Dermatology, Aarhus University Hospital, Aarhus, Denmark
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Im JY, Kim BK, Lee JY, Park SH, Ban HS, Jung KE, Won M. DDIAS suppresses TRAIL-mediated apoptosis by inhibiting DISC formation and destabilizing caspase-8 in cancer cells. Oncogene 2017; 37:1251-1262. [DOI: 10.1038/s41388-017-0025-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 08/16/2017] [Accepted: 09/27/2017] [Indexed: 11/09/2022]
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Houles T, Roux PP. Defining the role of the RSK isoforms in cancer. Semin Cancer Biol 2017; 48:53-61. [PMID: 28476656 DOI: 10.1016/j.semcancer.2017.04.016] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 04/10/2017] [Accepted: 04/28/2017] [Indexed: 02/03/2023]
Abstract
The 90kDa ribosomal S6 kinase (RSK) family is a group of Ser/Thr protein kinases (RSK1-4) that function downstream of the Ras/mitogen-activated protein kinase (MAPK) signalling pathway. RSK regulates many substrates involved in cell survival, growth, and proliferation, and as such, deregulated RSK activity has been associated with multiple cancer types. RSK expression and activity are dysregulated in several malignancies, including breast, prostate, and lung cancer, and available evidence suggests that RSK may be a promising cancer therapeutic target. Current limitations include the lack of RSK inhibitors with suitable pharmacokinetics and selectivity toward particular isoforms. This review briefly describes the current knowledge on RSK activation and function, with a particular emphasis on RSK-dependent mechanisms associated with tumorigenesis and pharmacological inhibition.
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Affiliation(s)
- Thibault Houles
- Institute for Research in Immunology and Cancer (IRIC), Canada
| | - Philippe P Roux
- Institute for Research in Immunology and Cancer (IRIC), Canada; Department of Pathology and Cell Biology, Faculty of Medicine, Université de Montréal, Montreal, Quebec, Canada.
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Chen JJ, Arur S. Discovering Functional ERK Substrates Regulating Caenorhabditis elegans Germline Development. Methods Mol Biol 2017; 1487:317-335. [PMID: 27924578 PMCID: PMC5429971 DOI: 10.1007/978-1-4939-6424-6_24] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/25/2023]
Abstract
The Rat Sarcoma (RAS) GTPAse-mediated extracellular signal-regulated kinase (ERK) pathway regulates multiple biological processes across metazoans. In particular during Caenorhabditis elegans oogenesis, ERK signaling has been shown to regulate over seven distinct biological processes in a temporal and sequential manner. To fully elucidate how ERK signaling cascade orchestrates these different biological processes in vivo, identification of the direct functional substrates of the pathway is critical. This chapter describes the methods that were used to identify ERK substrates in a global manner and study their functions in the germline. These approaches can also be generally applied to study ERK-dependent biological processes in other systems.
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Affiliation(s)
- Jessica Jie Chen
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX, USA
| | - Swathi Arur
- The University of Texas Graduate School of Biomedical Sciences, Houston, TX, USA.
- Department of Genetics, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Blvd., Houston, TX, 77030, USA.
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25
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Cho YY. RSK2 and its binding partners in cell proliferation, transformation and cancer development. Arch Pharm Res 2016; 40:291-303. [DOI: 10.1007/s12272-016-0880-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Accepted: 12/17/2016] [Indexed: 12/31/2022]
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Pellegrini E, Palencia A, Braun L, Kapp U, Bougdour A, Belrhali H, Bowler MW, Hakimi MA. Structural Basis for the Subversion of MAP Kinase Signaling by an Intrinsically Disordered Parasite Secreted Agonist. Structure 2016; 25:16-26. [PMID: 27889209 PMCID: PMC5222587 DOI: 10.1016/j.str.2016.10.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Revised: 09/21/2016] [Accepted: 10/25/2016] [Indexed: 01/07/2023]
Abstract
The causative agent of toxoplasmosis, the intracellular parasite Toxoplasma gondii, delivers a protein, GRA24, into the cells it infects that interacts with the mitogen-activated protein (MAP) kinase p38α (MAPK14), leading to activation and nuclear translocation of the host kinase and a subsequent inflammatory response that controls the progress of the parasite. The purification of a recombinant complex of GRA24 and human p38α has allowed the molecular basis of this activation to be determined. GRA24 is shown to be intrinsically disordered, binding two kinases that act independently, and is the only factor required to bypass the canonical mitogen-activated protein kinase activation pathway. An adapted kinase interaction motif (KIM) forms a highly stable complex that competes with cytoplasmic regulatory partners. In addition, the recombinant complex forms a powerful in vitro tool to evaluate the specificity and effectiveness of p38α inhibitors that have advanced to clinical trials, as it provides a hitherto unavailable stable and highly active form of p38α. Toxoplasmosis controls its host immune response via a protein effector, GRA24 A recombinant complex of GRA24 and MAPK p38α demonstrates how the protein works An adapted KIM domain ensures activation and a sustained inflammatory response The recombinant complex is useful in the evaluation of p38 inhibitors
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Affiliation(s)
- Erika Pellegrini
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble, France; Unit for Virus Host Cell Interactions, Université Grenoble Alpes-EMBL-CNRS, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble, France
| | - Andrés Palencia
- IAB, Team Host-Pathogen Interactions & Immunity to Infection, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38700 Grenoble, France
| | - Laurence Braun
- IAB, Team Host-Pathogen Interactions & Immunity to Infection, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38700 Grenoble, France
| | - Ulrike Kapp
- Structural Biology Group, European Synchrotron Radiation Facility, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble, France
| | - Alexandre Bougdour
- IAB, Team Host-Pathogen Interactions & Immunity to Infection, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38700 Grenoble, France
| | - Hassan Belrhali
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble, France; Unit for Virus Host Cell Interactions, Université Grenoble Alpes-EMBL-CNRS, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble, France.
| | - Matthew W Bowler
- European Molecular Biology Laboratory, Grenoble Outstation, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble, France; Unit for Virus Host Cell Interactions, Université Grenoble Alpes-EMBL-CNRS, 71 Avenue des Martyrs, CS 90181, 38042 Grenoble, France.
| | - Mohamed-Ali Hakimi
- IAB, Team Host-Pathogen Interactions & Immunity to Infection, INSERM U1209, CNRS UMR5309, Université Grenoble Alpes, 38700 Grenoble, France.
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Ohtake Y, Wong D, Abdul-Muneer PM, Selzer ME, Li S. Two PTP receptors mediate CSPG inhibition by convergent and divergent signaling pathways in neurons. Sci Rep 2016; 6:37152. [PMID: 27849007 PMCID: PMC5111048 DOI: 10.1038/srep37152] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2016] [Accepted: 10/25/2016] [Indexed: 01/29/2023] Open
Abstract
Receptor protein tyrosine phosphatase σ (PTPσ) and its subfamily member LAR act as transmembrane receptors that mediate growth inhibition of chondroitin sulfate proteoglycans (CSPGs). Inhibition of either receptor increases axon growth into and beyond scar tissues after CNS injury. However, it is unclear why neurons express two similar CSPG receptors, nor whether they use the same or different intracellular pathways. We have now studied the signaling pathways of these two receptors using N2A cells and primary neurons derived from knockout mice. We demonstrate that both receptors share certain signaling pathways (RhoA, Akt and Erk), but also use distinct signals to mediate CSPG actions. Activation of PTPσ by CSPGs selectively inactivated CRMP2, APC, S6 kinase and CREB. By contrast LAR activation inactivated PKCζ, cofilin and LKB1. For the first time, we propose a model of the signaling pathways downstream of these two CSPG receptors. We also demonstrate that deleting both receptors exhibits additive enhancement of axon growth in adult neuronal cultures in vitro. Our findings elucidate the novel downstream pathways of CSPGs and suggest potential synergy of blocking their two PTP receptors.
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Affiliation(s)
- Yosuke Ohtake
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
- Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Daniella Wong
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - P. M. Abdul-Muneer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
- Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Michael E. Selzer
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
- Department of Neurology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
| | - Shuxin Li
- Shriners Hospitals Pediatric Research Center, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
- Department of Anatomy and Cell Biology, Lewis Katz School of Medicine at Temple University, Philadelphia, PA 19140, USA
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Zhang Y, Zeng C, Lu S, Qin T, Yang L, Chen S, Chen J, Li Y. Identification of miR-125b targets involved in acute promyelocytic leukemia cell proliferation. Biochem Biophys Res Commun 2016; 478:1758-63. [PMID: 27613090 DOI: 10.1016/j.bbrc.2016.09.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 09/03/2016] [Indexed: 12/26/2022]
Abstract
Acute promyelocytic leukemia (APL) is characterized by the presence of the PML-RARα fusion protein. We have previously found that PML-RARα-regulated miR-125b is highly expressed in APL; however, the characteristics of the regulatory effects and mechanisms of miR-125b involved in APL proliferation have yet to be clarified. In this study, we demonstrate that miR-125b promotes the proliferation of APL cells with the involvement of the PI3K/Akt and MAPK signaling pathways. Furthermore, we identified BTG2, MAP3K11, RPS6KA1 and PRDM1 as putative targets of miR-125b, which we verified using luciferase reporter constructs. Moreover, we demonstrate that the expression of miR-125b targets is downregulated in leukemic cells in patients with APL. Thus, our results provide evidence that miR-125b can modulate multiple oncogenic cell proliferation pathways and may be a novel therapeutic target for APL.
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MESH Headings
- Adolescent
- Adult
- Blotting, Western
- Cell Line, Tumor
- Cell Proliferation/genetics
- Female
- Gene Expression Regulation, Leukemic
- Humans
- Immediate-Early Proteins/genetics
- Leukemia, Promyelocytic, Acute/genetics
- Leukemia, Promyelocytic, Acute/metabolism
- Leukemia, Promyelocytic, Acute/pathology
- MAP Kinase Kinase Kinases/genetics
- MAP Kinase Signaling System/genetics
- Male
- MicroRNAs/genetics
- Middle Aged
- Phosphatidylinositol 3-Kinases/metabolism
- Positive Regulatory Domain I-Binding Factor 1
- Repressor Proteins/genetics
- Reverse Transcriptase Polymerase Chain Reaction
- Ribosomal Protein S6 Kinases, 90-kDa/genetics
- Tumor Suppressor Proteins/genetics
- Young Adult
- Mitogen-Activated Protein Kinase Kinase Kinase 11
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Affiliation(s)
- Yikai Zhang
- Institute of Hematology, Medical College, Jinan University, Guangzhou, 510632, China; Key Laboratory for Regenerative Medicine of Ministry of Education, Jinan University, Guangzhou, 510632, China; First Affiliated Hospital, Jinan University, Guangzhou 510632, China
| | - Chengwu Zeng
- Institute of Hematology, Medical College, Jinan University, Guangzhou, 510632, China; Key Laboratory for Regenerative Medicine of Ministry of Education, Jinan University, Guangzhou, 510632, China; First Affiliated Hospital, Jinan University, Guangzhou 510632, China.
| | - Shuai Lu
- Institute of Hematology, Medical College, Jinan University, Guangzhou, 510632, China; Key Laboratory for Regenerative Medicine of Ministry of Education, Jinan University, Guangzhou, 510632, China
| | - Tianyu Qin
- Institute of Hematology, Medical College, Jinan University, Guangzhou, 510632, China
| | - Lijian Yang
- Institute of Hematology, Medical College, Jinan University, Guangzhou, 510632, China
| | - Shaohua Chen
- Institute of Hematology, Medical College, Jinan University, Guangzhou, 510632, China
| | - Jie Chen
- First Affiliated Hospital, Jinan University, Guangzhou 510632, China
| | - Yangqiu Li
- Institute of Hematology, Medical College, Jinan University, Guangzhou, 510632, China; Key Laboratory for Regenerative Medicine of Ministry of Education, Jinan University, Guangzhou, 510632, China; First Affiliated Hospital, Jinan University, Guangzhou 510632, China.
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Abstract
INTRODUCTION The p90 ribosomal S6 kinases (RSK) are a family of Ser/Thr protein kinases that are downstream effectors of MEK1/2-ERK1/2. Increased RSK activation is implicated in the etiology of multiple pathologies, including numerous types of cancers, cardiovascular disease, liver and lung fibrosis, and infections. AREAS COVERED The review summarizes the patent and scientific literature on small molecule modulators of RSK and their potential use as therapeutics. The patents were identified using World Intellectual Property Organization and United States Patent and Trademark Office databases. The compounds described are predominantly RSK inhibitors, but a RSK activator is also described. The majority of the inhibitors are not RSK-specific. EXPERT OPINION Based on the overwhelming evidence that RSK is involved in a number of diseases that have high mortalities it seems surprising that there are no RSK modulators that have pharmacokinetic properties suitable for in vivo use. MEK1/2 inhibitors are in the clinic, but the efficacy of these compounds appears to be limited by their side effects. We hypothesize that targeting the downstream effectors of MEK1/2, like RSK, are an untapped source of drug targets and that they will generate less side effects than MEK1/2 inhibitors because they regulate fewer effectors.
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Affiliation(s)
- Katarzyna A Ludwik
- a Department of Pathology, Microbiology & Immunology , Vanderbilt University , Nashville , TN , USA
| | - Deborah A Lannigan
- a Department of Pathology, Microbiology & Immunology , Vanderbilt University , Nashville , TN , USA.,b Department of Cancer Biology , Vanderbilt University , Nashville , TN , USA
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Functional Basis and Biophysical Approaches to Characterize the C-Terminal Domain of Human—Ribosomal S6 Kinases-3. Cell Biochem Biophys 2016; 74:317-25. [DOI: 10.1007/s12013-016-0745-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 06/09/2016] [Indexed: 10/21/2022]
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Zhou W, Li S, Lu W, Yuan J, Xu Y, Li H, Huang J, Zhao Z. Isoindole-1,3-dione derivatives as RSK2 inhibitors: synthesis, molecular docking simulation and SAR analysis. MEDCHEMCOMM 2016. [DOI: 10.1039/c5md00469a] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The present study reports a series of novel potent RSK2 inhibitors obtained from structure modifications of a virtual screening hit.
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Affiliation(s)
- Wei Zhou
- State Key Laboratory of Bioreactor Engineering
- Shanghai Key Laboratory of New Drug Design
- School of Pharmacy
- East China University of Science and Technology
- Shanghai 200237
| | - Shiliang Li
- State Key Laboratory of Bioreactor Engineering
- Shanghai Key Laboratory of New Drug Design
- School of Pharmacy
- East China University of Science and Technology
- Shanghai 200237
| | - Weiqiang Lu
- State Key Laboratory of Bioreactor Engineering
- Shanghai Key Laboratory of New Drug Design
- School of Pharmacy
- East China University of Science and Technology
- Shanghai 200237
| | - Jun Yuan
- State Key Laboratory of Bioreactor Engineering
- Shanghai Key Laboratory of New Drug Design
- School of Pharmacy
- East China University of Science and Technology
- Shanghai 200237
| | - Yufang Xu
- State Key Laboratory of Bioreactor Engineering
- Shanghai Key Laboratory of New Drug Design
- School of Pharmacy
- East China University of Science and Technology
- Shanghai 200237
| | - Honglin Li
- State Key Laboratory of Bioreactor Engineering
- Shanghai Key Laboratory of New Drug Design
- School of Pharmacy
- East China University of Science and Technology
- Shanghai 200237
| | - Jin Huang
- State Key Laboratory of Bioreactor Engineering
- Shanghai Key Laboratory of New Drug Design
- School of Pharmacy
- East China University of Science and Technology
- Shanghai 200237
| | - Zhenjiang Zhao
- State Key Laboratory of Bioreactor Engineering
- Shanghai Key Laboratory of New Drug Design
- School of Pharmacy
- East China University of Science and Technology
- Shanghai 200237
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32
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González-Vera JA, Morris MC. Fluorescent Reporters and Biosensors for Probing the Dynamic Behavior of Protein Kinases. Proteomes 2015; 3:369-410. [PMID: 28248276 PMCID: PMC5217393 DOI: 10.3390/proteomes3040369] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Revised: 09/30/2015] [Accepted: 10/23/2015] [Indexed: 12/20/2022] Open
Abstract
Probing the dynamic activities of protein kinases in real-time in living cells constitutes a major challenge that requires specific and sensitive tools tailored to meet the particular demands associated with cellular imaging. The development of genetically-encoded and synthetic fluorescent biosensors has provided means of monitoring protein kinase activities in a non-invasive fashion in their native cellular environment with high spatial and temporal resolution. Here, we review existing technologies to probe different dynamic features of protein kinases and discuss limitations where new developments are required to implement more performant tools, in particular with respect to infrared and near-infrared fluorescent probes and strategies which enable improved signal-to-noise ratio and controlled activation of probes.
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Affiliation(s)
- Juan A González-Vera
- Cell Cycle Biosensors & Inhibitors, Department of Amino Acids, Peptides and Proteins, Institute of Biomolecules Max Mousseron (IBMM) CNRS-UMR 5247, 15 Avenue Charles Flahault, Montpellier 34093, France.
| | - May C Morris
- Cell Cycle Biosensors & Inhibitors, Department of Amino Acids, Peptides and Proteins, Institute of Biomolecules Max Mousseron (IBMM) CNRS-UMR 5247, 15 Avenue Charles Flahault, Montpellier 34093, France.
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33
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Abe JI, Le NT, Heo KS. Role for SUMOylation in disturbed flow-induced atherosclerotic plaque formation. Biomed Eng Lett 2015. [DOI: 10.1007/s13534-015-0199-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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34
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Sati L, Soygur B, Celik-Ozenci C. Expression of Mammalian Target of Rapamycin and Downstream Targets in Normal and Gestational Diabetic Human Term Placenta. Reprod Sci 2015; 23:324-32. [DOI: 10.1177/1933719115602765] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Leyla Sati
- Department of Histology and Embryology, Akdeniz University School of Medicine, Antalya, Turkey
| | - Bikem Soygur
- Department of Histology and Embryology, Akdeniz University School of Medicine, Antalya, Turkey
| | - Ciler Celik-Ozenci
- Department of Histology and Embryology, Akdeniz University School of Medicine, Antalya, Turkey
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35
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Zhou F, Dong C, Davis JE, Wu WH, Surrao K, Wu G. The mechanism and function of mitogen-activated protein kinase activation by ARF1. Cell Signal 2015; 27:2035-2044. [PMID: 26169956 DOI: 10.1016/j.cellsig.2015.06.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Accepted: 06/24/2015] [Indexed: 01/25/2023]
Abstract
Mitogen-activated protein kinases (MAPK) can be activated by a number of biochemical pathways through distinct signaling molecules. We have recently revealed a novel function for the Ras-like small GTPase ADP-ribosylation factor 1 (ARF1) in mediating the activation of Raf1-MEK-ERK1/2 pathway by G protein-coupled receptors [Dong C, Li C and Wu G (2011) J Biol Chem 286, 43,361-43,369]. Here, we have further defined the underlying mechanism and the possible function of ARF1-mediated MAPK pathway. We demonstrated that the blockage of ARF1 activation and the disruption of ARF1 localization to the Golgi by mutating Thr48, a highly conserved residue involved in the exchange of GDP for GTP, and the myristoylation site Gly2 abolished ARF1's ability to activate ERK1/2. In addition, treatment with Golgi structure disrupting agents markedly attenuated ARF1-mediated ERK1/2 activation. Furthermore, ARF1 significantly promoted cell proliferation. More interestingly, ARF1 activated 90kDa ribosomal S6 kinase 1 (RSK1) without influencing Elk-1 activation and ERK2 translocation to the nuclei. These data demonstrate that, once activated, ARF1 activates the MAPK pathway likely using the Golgi as a main platform, which in turn activates the cytoplasmic RSK1, leading to cell proliferation.
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Affiliation(s)
- Fuguo Zhou
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, 1901 Perdido St, New Orleans, LA 70112, United States
| | - Chunmin Dong
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, 1901 Perdido St, New Orleans, LA 70112, United States
| | - Jason E Davis
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta, GA 30912, United States
| | - William H Wu
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta, GA 30912, United States
| | - Kristen Surrao
- Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta, GA 30912, United States
| | - Guangyu Wu
- Department of Pharmacology and Experimental Therapeutics, Louisiana State University Health Sciences Center, 1901 Perdido St, New Orleans, LA 70112, United States.,Department of Pharmacology and Toxicology, Medical College of Georgia, Georgia Regents University, 1459 Laney Walker Blvd., Augusta, GA 30912, United States
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36
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Jung E, Cho JY, Park D, Kim MH, Park B, Lee SY, Lee J. Vegetable peptones increase production of type I collagen in human fibroblasts by inducing the RSK-CCAAT/enhancer binding protein-β phosphorylation pathway. Nutr Res 2015; 35:127-35. [PMID: 25464949 DOI: 10.1016/j.nutres.2014.10.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2014] [Revised: 10/20/2014] [Accepted: 10/22/2014] [Indexed: 02/08/2023]
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Abstract
Atherosclerosis is a focal disease that develops preferentially where nonlaminar, disturbed blood flow occurs, such as branches, bifurcations, and curvatures of large arteries. Endothelial cells sense and respond differently to disturbed flow compared with steady laminar flow. Disturbed flow that occurs in so-called atheroprone areas activates proinflammatory and apoptotic signaling, and this results in endothelial dysfunction and leads to subsequent development of atherosclerosis. In contrast, steady laminar flow as atheroprotective flow promotes expression of many anti-inflammatory genes, such as Kruppel-like factor 2 and endothelial nitric oxide synthase and inhibits endothelial inflammation and athrogenesis. Here we will discuss that disturbed flow and steady laminar flow induce pro- and antiatherogenic events via flow type-specific mechanotransduction pathways. We will focus on 5 mechanosensitive pathways: mitogen-activated protein kinases/extracellular signal-regulated kinase 5/Kruppel-like factor 2 signaling, extracellular signal-regulated kinase/peroxisome proliferator-activated receptor signaling, and mechanosignaling pathways involving SUMOylation, protein kinase C-ζ, and p90 ribosomal S6 kinase. We think that clarifying regulation mechanisms between these 2 flow types will provide new insights into therapeutic approaches for the prevention and treatment of atherosclerosis.
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Affiliation(s)
- Jun-ichi Abe
- From the Aab Cardiovascular Research Institute, University of Rochester, NY.
| | - Bradford C Berk
- From the Aab Cardiovascular Research Institute, University of Rochester, NY.
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Synthetic lethality screen identifies RPS6KA2 as modifier of epidermal growth factor receptor activity in pancreatic cancer. Neoplasia 2014; 15:1354-62. [PMID: 24403857 DOI: 10.1593/neo.131660] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Revised: 11/14/2013] [Accepted: 11/19/2013] [Indexed: 12/20/2022] Open
Abstract
Pancreatic cancer is characterized by a high degree of resistance to chemotherapy. Epidermal growth factor receptor (EGFR) inhibition using the small-molecule inhibitor erlotinib was shown to provide a small survival benefit in a subgroup of patients. To identify kinases whose inhibition acts synergistically with erlotinib, we employed a kinome-wide small-interfering RNA (siRNA)-based loss-of-function screen in the presence of erlotinib. Of 779 tested kinases, we identified several targets whose inhibition acted synergistically lethal with EGFR inhibition by erlotinib, among them the S6 kinase ribosomal protein S6 kinase 2 (RPS6KA2)/ribosomal S6 kinase 3. Activated RPS6KA2 was expressed in approximately 40% of 123 human pancreatic cancer tissues. RPS6KA2 was shown to act downstream of EGFR/RAS/mitogen-activated protein kinase kinase (MEK)/extracellular-signal regulated kinase (ERK) signaling and was activated by EGF independently of the presence of KRAS mutations. Knockdown of RPS6KA2 by siRNA led to increased apoptosis only in the presence of erlotinib, whereas RPS6KA2 activation or overexpression rescued from erlotinib- and gemcitabine-induced apoptosis. This effect was at least in part mediated by downstream activation of ribosomal protein S6. Genetic as well as pharmacological inhibition of RPS6KA2 by the inhibitor BI-D1870 acted synergistically with erlotinib. By applying this synergistic lethality screen using a kinome-wide RNA interference-library approach, we identified RPS6KA2 as potential drug target whose inhibition synergistically enhanced the effect of erlotinib on tumor cell survival. This kinase therefore represents a promising drug candidate suitable for the development of novel inhibitors for pancreatic cancer therapy.
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Phosphorylation of RSK2 at Tyr529 by FGFR2-p38 enhances human mammary epithelial cells migration. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2461-70. [PMID: 25014166 DOI: 10.1016/j.bbamcr.2014.06.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 06/29/2014] [Accepted: 06/30/2014] [Indexed: 01/08/2023]
Abstract
The members of p90 ribosomal S6 kinase (RSK) family of Ser/Thr kinases are downstream effectors of MAPK/ERK pathway that regulate diverse cellular processes including cell growth, proliferation and survival. In carcinogenesis, RSKs are thought to modulate cell motility, invasion and metastasis. Herein, we have studied an involvement of RSKs in FGF2/FGFR2-driven behaviours of mammary epithelial and breast cancer cells. We found that both silencing and inhibiting of FGFR2 attenuated phosphorylation of RSKs, whereas FGFR2 overexpression and/or its stimulation with FGF2 enhanced RSKs activity. Moreover, treatment with ERK, Src and p38 inhibitors revealed that p38 kinase acts as an upstream RSK2 regulator. We demonstrate for the first time that in FGF2/FGFR2 signalling, p38 but not MEK/ERK, indirectly activated RSK2 at Tyr529, which facilitated phosphorylation of its other residues (Thr359/Ser363, Thr573 and Ser380). In contrast to FGF2-triggered signalling, inhibition of p38 in the EGF pathway affected only RSK2-Tyr529, without any impact on the remaining RSK phosphorylation sites. p38-mediated phosphorylation of RSK2-Tyr529 was crucial for the transactivation of residues located at kinase C-terminal domain and linker-region, specifically, in the FGF2/FGFR2 signalling pathway. Furthermore, we show that FGF2 promoted anchorage-independent cell proliferation, formation of focal adhesions and cell migration, which was effectively abolished by treatment with RSKs inhibitor (FMK). These indicate that RSK2 activity is indispensable for FGF2/FGFR2-mediated cellular effects. Our findings identified a new FGF2/FGFR2-p38-RSK2 pathway, which may play a significant role in the pathogenesis and progression of breast cancer and, hence, may present a novel therapeutic target in the treatment of FGFR2-expressing tumours.
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PPARγ recruitment to active ERK during memory consolidation is required for Alzheimer's disease-related cognitive enhancement. J Neurosci 2014; 34:4054-63. [PMID: 24623782 DOI: 10.1523/jneurosci.4024-13.2014] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Cognitive impairment is a quintessential feature of Alzheimer's disease (AD) and AD mouse models. The peroxisome proliferator-activated receptor-γ (PPARγ) agonist rosiglitazone improves hippocampus-dependent cognitive deficits in some AD patients and ameliorates deficits in the Tg2576 mouse model for AD amyloidosis. Tg2576 cognitive enhancement occurs through the induction of a gene and protein expression profile reflecting convergence of the PPARγ signaling axis and the extracellular signal-regulated protein kinase (ERK) cascade, a critical mediator of memory consolidation. We therefore tested whether PPARγ and ERK associated in protein complexes that subserve cognitive enhancement through PPARγ agonism. Coimmunoprecipitation of hippocampal extracts revealed that PPARγ and activated, phosphorylated ERK (pERK) associated in Tg2576 in vivo, and that PPARγ agonism facilitated recruitment of PPARγ to pERK during memory consolidation. Furthermore, the amount of PPARγ recruited to pERK correlated with the cognitive reserve in humans with AD and in Tg2576. Our findings implicate a previously unidentified PPARγ-pERK complex that provides a molecular mechanism for the convergence of these pathways during cognitive enhancement, thereby offering new targets for therapeutic development in AD.
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Duan RB, Zhang L, Chen DF, Yang F, Yang JS, Yang WJ. Two p90 ribosomal S6 kinase isoforms are involved in the regulation of mitotic and meiotic arrest in Artemia. J Biol Chem 2014; 289:16006-15. [PMID: 24755224 DOI: 10.1074/jbc.m114.553370] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
There are multiple isoforms of p90 ribosomal S6 kinase (RSK), which regulate diverse cellular functions such as cell growth, proliferation, maturation, and motility. However, the relationship between the structures and functions of RSK isoforms remains undetermined. Artemia is a useful model in which to study cell cycle arrest because these animals undergo prolonged diapauses, a state of obligate dormancy. A novel RSK isoform was identified in Artemia, which was termed Ar-Rsk2. This isoform was compared with an RSK isoform that we previously identified in Artemia, termed Ar-Rsk1. Ar-Rsk2 has an ERK-docking motif, whereas Ar-Rsk1 does not. Western blot analysis revealed that Ar-Rsk1 was activated by phosphorylation, which blocked meiosis in oocytes. Knockdown of Ar-Rsk1 reduced the level of phosphorylated cdc2 and thereby suppressed cytostatic factor activity. This indicates that Ar-Rsk1 regulates the cytostatic factor in meiosis. Expression of Ar-Rsk2 was down-regulated in Artemia cysts in which mitosis was arrested. Knockdown of Ar-Rsk2 resulted in decreased levels of cyclin D3 and phosphorylated histone H3, and the production of pseudo-diapause cysts. This indicates that Ar-Rsk2 regulates mitotic arrest. PLK and ERK RNAi showed that Ar-Rsk2, but not Ar-Rsk1, could be activated by PLK-ERK in Artemia. This is the first study to report that RSK isoforms with and without an ERK-docking motif regulate mitosis and meiosis, respectively. This study provides insight into the relationship between the structures and functions of RSK isoforms.
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Affiliation(s)
- Ru-Bing Duan
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Li Zhang
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Dian-Fu Chen
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Fan Yang
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Jin-Shu Yang
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
| | - Wei-Jun Yang
- From the Key Laboratory of Conservation Biology for Endangered Wildlife of the Ministry of Education and College of Life Sciences, Zhejiang University, Hangzhou, Zhejiang 310058, China
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Jagilinki BP, Gadewal N, Mehta H, Mahadik H, Pandey V, Sawant U, A Wadegaonkar P, Goyal P, Kumar S, K Varma A. Conserved residues at the MAPKs binding interfaces that regulate transcriptional machinery. J Biomol Struct Dyn 2014; 33:852-60. [PMID: 24739067 DOI: 10.1080/07391102.2014.915764] [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: 10/25/2022]
Abstract
Signaling through c-Raf downstream pathways is the crucial subject of extensive studies because over expressed or mutated genes in this pathway lead to a variety of human cancers. On the basis of cellular localization, this pathway has been sub-divided into two cascades. The first RAF1-MEK1-ERK2 cascade which remains in the cytosol, whereas the second MEK1-ERK2-RSKs transduces into the nucleus and regulates the transactivation function. But how a few amino acids critically regulate the transcriptional function remains unclear. In this paper, we have performed in silico studies to unravel how atomic complexities at the MEK1-ERK2-RSKs pathways intercedes different functional responses. The secondary structure of the ERK, RSKs have been modeled using Jpred3, PSI-PHRED, protein modeler, and Integrated sequence analyzer from Discovery Studio software. Peptides of RSKs isozymes (RSK1/2/3/4) were built and docked on ERK2 structure using ZDOCK module. The hydropathy index for the RSKs molecules was determined using the KYTE-DOOLITTLE plot. The simulations of complex molecules were carried out using a CHARMM force field. The protein-protein interactions (PPIs) in different cascade of MAP kinase (MAPK) have been shown to be similar to those predicted in vivo. PPIs elucidate that the amino acids located at the conserved domains of MAPK pathways are responsible for transactivation functions.
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Affiliation(s)
- Bhanu P Jagilinki
- a Tata Memorial Centre, Advanced Centre for Treatment, Research and Education in Cancer , Kharghar, Navi Mumbai 410 210 , Maharashtra , India
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Chen C, Zhang L, Huang NJ, Huang B, Kornbluth S. Suppression of DNA-damage checkpoint signaling by Rsk-mediated phosphorylation of Mre11. Proc Natl Acad Sci U S A 2013; 110:20605-10. [PMID: 24297933 PMCID: PMC3870678 DOI: 10.1073/pnas.1306328110] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Ataxia telangiectasia mutant (ATM) is an S/T-Q-directed kinase that is critical for the cellular response to double-stranded breaks (DSBs) in DNA. Following DNA damage, ATM is activated and recruited by the MRN protein complex [meiotic recombination 11 (Mre11)/DNA repair protein Rad50/Nijmegen breakage syndrome 1 proteins] to sites of DNA damage where ATM phosphorylates multiple substrates to trigger cell-cycle arrest. In cancer cells, this regulation may be faulty, and cell division may proceed even in the presence of damaged DNA. We show here that the ribosomal s6 kinase (Rsk), often elevated in cancers, can suppress DSB-induced ATM activation in both Xenopus egg extracts and human tumor cell lines. In analyzing each step in ATM activation, we have found that Rsk targets loading of MRN complex components onto DNA at DSB sites. Rsk can phosphorylate the Mre11 protein directly at S676 both in vitro and in intact cells and thereby can inhibit the binding of Mre11 to DNA with DSBs. Accordingly, mutation of S676 to Ala can reverse inhibition of the response to DSBs by Rsk. Collectively, these data point to Mre11 as an important locus of Rsk-mediated checkpoint inhibition acting upstream of ATM activation.
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Affiliation(s)
- Chen Chen
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710
| | - Liguo Zhang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710
| | - Nai-Jia Huang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710
| | - Bofu Huang
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710
| | - Sally Kornbluth
- Department of Pharmacology and Cancer Biology, Duke University School of Medicine, Durham, NC 27710
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c-Jun N-terminal kinase in synergistic neurite outgrowth in PC12 cells mediated through P90RSK. BMC Neurosci 2013; 14:153. [PMID: 24330599 PMCID: PMC4029309 DOI: 10.1186/1471-2202-14-153] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2013] [Accepted: 12/05/2013] [Indexed: 12/02/2022] Open
Abstract
Background Synergistic multi-ligand treatments that can induce neuronal differentiation offer valuable strategies to regulate and modulate neurite outgrowth. Whereas the signaling pathways mediating single ligand-induced neurite outgrowth, such as Akt, extracellular signal-regulated kinase (Erk), c-Jun N-terminal kinase (JNK), and p38 mitogen-activated protein kinase (P38), have been extensively studied, the mechanisms underlying multi-ligand synergistic neurite outgrowth are poorly understood. In an attempt to gain insight into synergistic neurite outgrowth, PC12 cells were treated with one of three combinations: pituitary adenylate cyclase-activating peptide (PACAP) with epidermal growth factor (EP), basic fibroblast growth factor (FP), or nerve growth factor (NP) and then challenged with the appropriate kinase inhibitors to assess the signaling pathways involved in the process. Results Response surface analyses indicated that synergistic neurite outgrowth was regulated by distinct pathways in these systems. Synergistic increases in the phosphorylation of Erk and JNK, but not Akt or P38, were observed with the three growth factor-PACAP combinations. Unexpectedly, we identified a synergistic increase in JNK phosphorylation, which was involved in neurite outgrowth in the NP and FP, but not EP, systems. Inhibition of JNK using the SP600125 inhibitor reduced phosphorylation of 90 kDa ribosomal S6 kinase (P90RSK) in the NP and FP, but not EP, systems. This suggested the involvement of P90RSK in mediating the differential effects of JNK in synergistic neurite outgrowth. Conclusions Taken together, these findings reveal the involvement of distinct signaling pathways in regulating neurite outgrowth in response to different synergistic growth factor-PACAP treatments. Our findings demonstrate a hitherto unrecognized mechanism of JNK-P90RSK in mediating synergistic neurite outgrowth induced by the co-treatment of growth factors and PACAP.
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Gao X, Lin B, Sadayappan S, Patel TB. Interactions between the regulatory subunit of type I protein kinase A and p90 ribosomal S6 kinase1 regulate cardiomyocyte apoptosis. Mol Pharmacol 2013; 85:357-67. [PMID: 24307699 DOI: 10.1124/mol.113.090613] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Cardiomyocyte apoptosis contributes toward the loss of muscle mass in myocardial pathologies. Previous reports have implicated type I cAMP-dependent protein kinase (PKA) and p90 ribosomal S6 kinase (RSK) in cardiomyocyte apoptosis. However, the precise mechanisms and the isoform of RSK involved in this process remain undefined. Using adult rat ventricular myocytes and mouse-derived cardiac HL-1 cardiomyocytes, we demonstrate that hypoxia/reoxygenation (H/R)-induced apoptosis is accompanied by a decrease in the type I PKA regulatory subunit (PKARIα) and activation of RSK1. As previously described by us for other cell types, in cardiomyocytes, inactive RSK1 also interacts with PKARIα, whereas the active RSK1 interacts with the catalytic subunit of PKA. Additionally, small interfering (siRNA)-mediated silencing of PKARIα or disrupting the RSK1/PKARIα interactions with a small, cell-permeable peptide activates RSK1 and recapitulates the H/R-induced apoptosis. Inhibition of RSK1 or siRNA-mediated silencing of RSK1 attenuates H/R-induced apoptosis, demonstrating the role of RSK1 in cardiomyocyte apoptosis. Furthermore, silencing of RSK1 decreases the H/R-induced phosphorylation of sodium-hydrogen exchanger 1 (NHE1), and inhibition of NHE1 with 5'-N-ethyl-N-isopropyl-amiloride blocks H/R induced apoptosis, indicating the involvement of NHE1 in apoptosis. Overall, our findings demonstrate that H/R-mediated decrease in PKARIα protein levels leads to activation of RSK1, which via phosphorylation of NHE1 induces cardiomyocyte apoptosis.
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Affiliation(s)
- Xianlong Gao
- Department of Molecular Pharmacology & Therapeutics and Signal Transduction Research Institute (X.G., T.B.P.), and the Department of Molecular and Cellular Physiology (B.L., S.S.), Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois
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Peti W, Page R. Molecular basis of MAP kinase regulation. Protein Sci 2013; 22:1698-710. [PMID: 24115095 DOI: 10.1002/pro.2374] [Citation(s) in RCA: 217] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 09/09/2013] [Accepted: 09/10/2013] [Indexed: 12/11/2022]
Abstract
Mitogen-activated protein kinases (MAPKs; ERK1/2, p38, JNK, and ERK5) have evolved to transduce environmental and developmental signals (growth factors, stress) into adaptive and programmed responses (differentiation, inflammation, apoptosis). Almost 20 years ago, it was discovered that MAPKs contain a docking site in the C-terminal lobe that binds a conserved 13-16 amino acid sequence known as the D- or KIM-motif (kinase interaction motif). Recent crystal structures of MAPK:KIM-peptide complexes are leading to a precise understanding of how KIM sequences contribute to MAPK selectivity. In addition, new crystal and especially NMR studies are revealing how residues outside the canonical KIM motif interact with specific MAPKs and contribute further to MAPK selectivity and signaling pathway fidelity. In this review, we focus on these recent studies, with an emphasis on the use of NMR spectroscopy, isothermal titration calorimetry and small angle X-ray scattering to investigate these processes.
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Affiliation(s)
- Wolfgang Peti
- Department of Molecular Pharmacology, Physiology and Biotechnology, Brown University, Providence, Rhode Island, 02912; Department of Chemistry, Brown University, Providence, Rhode Island, 02912
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Gomar-Alba M, Alepuz P, del Olmo M. Dissection of the elements of osmotic stress response transcription factor Hot1 involved in the interaction with MAPK Hog1 and in the activation of transcription. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:1111-25. [DOI: 10.1016/j.bbagrm.2013.07.009] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2013] [Revised: 07/26/2013] [Accepted: 07/29/2013] [Indexed: 01/15/2023]
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Lara R, Seckl MJ, Pardo OE. The p90 RSK family members: common functions and isoform specificity. Cancer Res 2013; 73:5301-8. [PMID: 23970478 DOI: 10.1158/0008-5472.can-12-4448] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The p90 ribosomal S6 kinases (RSK) are implicated in various cellular processes, including cell proliferation, survival, migration, and invasion. In cancer, RSKs modulate cell transformation, tumorigenesis, and metastasis. Indeed, changes in the expression of RSK isoforms have been reported in several malignancies, including breast, prostate, and lung cancers. Four RSK isoforms have been identified in humans on the basis of their high degree of sequence homology. Although this similarity suggests some functional redundancy between these proteins, an increasing body of evidence supports the existence of isoform-based specificity among RSKs in mediating particular cellular processes. This review briefly presents the similarities between RSK family members before focusing on the specific function of each of the isoforms and their involvement in cancer progression.
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Affiliation(s)
- Romain Lara
- Division of Oncology, Oncology Imperial College London, London, United Kingdom
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Arul N, Cho YY. A Rising Cancer Prevention Target of RSK2 in Human Skin Cancer. Front Oncol 2013; 3:201. [PMID: 23936765 PMCID: PMC3733026 DOI: 10.3389/fonc.2013.00201] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2013] [Accepted: 07/23/2013] [Indexed: 02/06/2023] Open
Abstract
RSK2 is a p90 ribosomal S6 kinase family (p90(RSK)) member regulating cell proliferation and transformation induced by tumor promoters such as epithelial growth factor (EGF) and 12-O-tetradecanoylphorbol-13-acetate. This family of p90(RSK) has classified as a serine/threonine kinase that respond to many growth factors, peptide hormones, neurotransmitters, and environmental stresses such as ultraviolet (UV) light. Our recent study demonstrates that RSK2 plays a key role in human skin cancer development. Activation of RSK2 by EGF and UV through extracellular-activated protein kinases signaling pathway induces cell cycle progression, cell proliferation, and anchorage-independent cell transformation. Moreover, knockdown of RSK2 by si-RNA or sh-RNA abrogates cell proliferation and cell transformation of non-malignant human skin keratinocyte, and colony growth of malignant melanoma (MM) cells in soft agar. Importantly, activated and total RSK2 protein levels are highly detected in human skin cancer tissues including squamous cell carcinoma, basal-cell carcinoma, and MM. Kaempferol and eriodictyol are natural substances to inhibit kinase activity of the RSK2 N-terminal kinase domain, which is a critical kinase domain to transduce their activation signals to the substrates by phosphorylation. In this review, we discuss the role of RSK2 in skin cancer, particularly in activation of signaling pathways and potent natural substances to target RSK2 as chemopreventive and therapeutic agents.
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Affiliation(s)
- Narayanasamy Arul
- College of Pharmacy, The Catholic University of Korea, Bucheon-si, Republic of Korea
| | - Yong-Yeon Cho
- College of Pharmacy, The Catholic University of Korea, Bucheon-si, Republic of Korea
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From FRET Imaging to Practical Methodology for Kinase Activity Sensing in Living Cells. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2013; 113:145-216. [DOI: 10.1016/b978-0-12-386932-6.00005-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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