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RAS Dimers: The Novice Couple at the RAS-ERK Pathway Ball. Genes (Basel) 2021; 12:genes12101556. [PMID: 34680951 PMCID: PMC8535645 DOI: 10.3390/genes12101556] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 09/27/2021] [Accepted: 09/28/2021] [Indexed: 02/07/2023] Open
Abstract
Signals conveyed through the RAS-ERK pathway constitute a pivotal regulatory element in cancer-related cellular processes. Recently, RAS dimerization has been proposed as a key step in the relay of RAS signals, critically contributing to RAF activation. RAS clustering at plasma membrane microdomains and endomembranes facilitates RAS dimerization in response to stimulation, promoting RAF dimerization and subsequent activation. Remarkably, inhibiting RAS dimerization forestalls tumorigenesis in cellular and animal models. Thus, the pharmacological disruption of RAS dimers has emerged as an additional target for cancer researchers in the quest for a means to curtail aberrant RAS activity.
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A Crosstalk Between Dual-Specific Phosphatases and Dual-Specific Protein Kinases Can Be A Potential Therapeutic Target for Anti-cancer Therapy. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021; 1275:357-382. [PMID: 33539023 DOI: 10.1007/978-3-030-49844-3_14] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
While protein tyrosine kinases (PTKs) play an initiative role in growth factor-mediated cellular processes, protein tyrosine phosphatases (PTPs) negatively regulates these processes, acting as tumor suppressors. Besides selective tyrosine dephosphorylation of PTKs via PTPs may affect oncogenic pathways during carcinogenesis. The PTP family contains a group of dual-specificity phosphatases (DUSPs) that regulate the activity of Mitogen-activated protein kinases (MAPKs), which are key effectors in the control of cell growth, proliferation and survival. Abnormal MAPK signaling is critical for initiation and progression stages of carcinogenesis. Since depletion of DUSP-MAPK phosphatases (MKPs) can reduce tumorigenicity, altering MAPK signaling by DUSP-MKP inhibitors could be a novel strategy in anti-cancer therapy. Moreover, Cdc25A is, a DUSP and a key regulator of the cell cycle, promotes cell cycle progression by dephosphorylating and activating cyclin-dependent kinases (CDK). Cdc25A-CDK pathway is a novel mechanism in carcinogenesis. Besides the mammalian target of rapamycin (mTOR) kinase inhibitors or mammalian target of rapamycin complex 1 (mTORC1) inhibition in combination with the dual phosphatidylinositol 3 kinase (PI3K)/mTOR or AKT kinase inhibitors are more effective in inhibiting the phosphorylation of eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1) and cap-dependent translation. Dual targeting of the Akt and mTOR signaling pathways regulates cellular growth, proliferation and survival. Like the Cdc2-like kinases (CLK), dual-specific tyrosine phosphorylation-regulated kinases (DYRKs) are essential for the regulation of cell fate. The crosstalk between dual-specific phosphatases and dual- specific protein kinases is a novel drug target for anti-cancer therapy. Therefore, the focus of this chapter involves protein kinase modules, critical biochemical checkpoints of cancer therapy and the synergistic effects of protein kinases and anti-cancer molecules.
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Lang R, Raffi FAM. Dual-Specificity Phosphatases in Immunity and Infection: An Update. Int J Mol Sci 2019; 20:ijms20112710. [PMID: 31159473 PMCID: PMC6600418 DOI: 10.3390/ijms20112710] [Citation(s) in RCA: 80] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Revised: 05/28/2019] [Accepted: 05/30/2019] [Indexed: 12/26/2022] Open
Abstract
Kinase activation and phosphorylation cascades are key to initiate immune cell activation in response to recognition of antigen and sensing of microbial danger. However, for balanced and controlled immune responses, the intensity and duration of phospho-signaling has to be regulated. The dual-specificity phosphatase (DUSP) gene family has many members that are differentially expressed in resting and activated immune cells. Here, we review the progress made in the field of DUSP gene function in regulation of the immune system during the last decade. Studies in knockout mice have confirmed the essential functions of several DUSP-MAPK phosphatases (DUSP-MKP) in controlling inflammatory and anti-microbial immune responses and support the concept that individual DUSP-MKP shape and determine the outcome of innate immune responses due to context-dependent expression and selective inhibition of different mitogen-activated protein kinases (MAPK). In addition to the canonical DUSP-MKP, several small-size atypical DUSP proteins regulate immune cells and are therefore also reviewed here. Unexpected and complex findings in DUSP knockout mice pose new questions regarding cell type-specific and redundant functions. Another emerging question concerns the interaction of DUSP-MKP with non-MAPK binding partners and substrate proteins. Finally, the pharmacological targeting of DUSPs is desirable to modulate immune and inflammatory responses.
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Affiliation(s)
- Roland Lang
- Institute of Clinical Microbiology, Immunology and Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
| | - Faizal A M Raffi
- Institute of Clinical Microbiology, Immunology and Hygiene, Universitätsklinikum Erlangen, Friedrich-Alexander-Universität Erlangen-Nürnberg, 91054 Erlangen, Germany.
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Hey F, Andreadi C, Noble C, Patel B, Jin H, Kamata T, Straatman K, Luo J, Balmanno K, Jones DT, Collins VP, Cook SJ, Caunt CJ, Pritchard C. Over-expressed, N-terminally truncated BRAF is detected in the nucleus of cells with nuclear phosphorylated MEK and ERK. Heliyon 2018; 4:e01065. [PMID: 30603699 PMCID: PMC6304467 DOI: 10.1016/j.heliyon.2018.e01065] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Revised: 09/12/2018] [Accepted: 12/14/2018] [Indexed: 12/31/2022] Open
Abstract
BRAF is a cytoplasmic protein kinase, which activates the MEK-ERK signalling pathway. Deregulation of the pathway is associated with the presence of BRAF mutations in human cancer, the most common being V600E BRAF, although structural rearrangements, which remove N-terminal regulatory sequences, have also been reported. RAF-MEK-ERK signalling is normally thought to occur in the cytoplasm of the cell. However, in an investigation of BRAF localisation using fluorescence microscopy combined with subcellular fractionation of Green Fluorescent Protein (GFP)-tagged proteins expressed in NIH3T3 cells, surprisingly, we detected N-terminally truncated BRAF (ΔBRAF) in both nuclear and cytoplasmic compartments. In contrast, ΔCRAF and full-length, wild-type BRAF (WTBRAF) were detected at lower levels in the nucleus while full-length V600EBRAF was virtually excluded from this compartment. Similar results were obtained using ΔBRAF tagged with the hormone-binding domain of the oestrogen receptor (hbER) and with the KIAA1549-ΔBRAF translocation mutant found in human pilocytic astrocytomas. Here we show that GFP-ΔBRAF nuclear translocation does not involve a canonical Nuclear Localisation Signal (NLS), but is suppressed by N-terminal sequences. Nuclear GFP-ΔBRAF retains MEK/ERK activating potential and is associated with the accumulation of phosphorylated MEK and ERK in the nucleus. In contrast, full-length GFP-WTBRAF and GFP-V600EBRAF are associated with the accumulation of phosphorylated ERK but not phosphorylated MEK in the nucleus. These data have implications for cancers bearing single nucleotide variants or N-terminal deleted structural variants of BRAF.
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Affiliation(s)
- Fiona Hey
- Department of Molecular Cell Biology, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Catherine Andreadi
- Leicester Cancer Research Centre, Clinical Sciences Building, University of Leicester, Leicester Royal Infirmary, Leicester LE2 7LX, UK
| | - Catherine Noble
- Department of Molecular Cell Biology, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Bipin Patel
- Department of Molecular Cell Biology, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Hong Jin
- Department of Molecular Cell Biology, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Tamihiro Kamata
- Leicester Cancer Research Centre, Clinical Sciences Building, University of Leicester, Leicester Royal Infirmary, Leicester LE2 7LX, UK
| | - Kees Straatman
- Core Biotechnology Services, University of Leicester, Lancaster Road, Leicester LE1 9HN, UK
| | - Jinli Luo
- Leicester Cancer Research Centre, Clinical Sciences Building, University of Leicester, Leicester Royal Infirmary, Leicester LE2 7LX, UK
| | - Kathryn Balmanno
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - David T.W. Jones
- Department of Pathology, Division of Molecular Histopathology, University of Cambridge, Cambridge CB2 0QQ, UK
| | - V. Peter Collins
- Department of Pathology, Division of Molecular Histopathology, University of Cambridge, Cambridge CB2 0QQ, UK
| | - Simon J. Cook
- Signalling Laboratory, The Babraham Institute, Babraham Research Campus, Cambridge CB22 3AT, UK
| | - Christopher J. Caunt
- Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Catrin Pritchard
- Leicester Cancer Research Centre, Clinical Sciences Building, University of Leicester, Leicester Royal Infirmary, Leicester LE2 7LX, UK
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