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Mozzarelli AM, Simanshu DK, Castel P. Functional and structural insights into RAS effector proteins. Mol Cell 2024; 84:2807-2821. [PMID: 39025071 PMCID: PMC11316660 DOI: 10.1016/j.molcel.2024.06.027] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Revised: 06/24/2024] [Accepted: 06/25/2024] [Indexed: 07/20/2024]
Abstract
RAS proteins are conserved guanosine triphosphate (GTP) hydrolases (GTPases) that act as molecular binary switches and play vital roles in numerous cellular processes. Upon GTP binding, RAS GTPases adopt an active conformation and interact with specific proteins termed RAS effectors that contain a conserved ubiquitin-like domain, thereby facilitating downstream signaling. Over 50 effector proteins have been identified in the human proteome, and many have been studied as potential mediators of RAS-dependent signaling pathways. Biochemical and structural analyses have provided mechanistic insights into these effectors, and studies using model organisms have complemented our understanding of their role in physiology and disease. Yet, many critical aspects regarding the dynamics and biological function of RAS-effector complexes remain to be elucidated. In this review, we discuss the mechanisms and functions of known RAS effector proteins, provide structural perspectives on RAS-effector interactions, evaluate their significance in RAS-mediated signaling, and explore their potential as therapeutic targets.
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Affiliation(s)
- Alessandro M Mozzarelli
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA; Laura and Isaac Perlmutter NYU Cancer Center, NYU Langone Health, New York, NY, USA
| | - Dhirendra K Simanshu
- NCI RAS Initiative, Cancer Research Technology Program, Frederick National Laboratory for Cancer Research, Frederick, MD, USA.
| | - Pau Castel
- Department of Biochemistry and Molecular Pharmacology, NYU Grossman School of Medicine, New York, NY, USA; Laura and Isaac Perlmutter NYU Cancer Center, NYU Langone Health, New York, NY, USA.
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2
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Lyu H, Chamberlin HM. Functional distinction in oncogenic Ras variant activity in Caenorhabditis elegans. Dis Model Mech 2024; 17:dmm050577. [PMID: 38946472 PMCID: PMC11340813 DOI: 10.1242/dmm.050577] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2023] [Accepted: 06/21/2024] [Indexed: 07/02/2024] Open
Abstract
Ras genes are important oncogenes that are frequently mutated in cancer. Human oncogenic variants exhibit functional distinctions in terms of their representation in different cancer types, impact on cellular targets and sensitivity to pharmacological treatments. However, how these distinct variants influence and respond to the cellular networks in which they are embedded is poorly understood. To identify novel participants in the complex interplay between Ras genotype and cell interaction networks in vivo, we have developed and tested an experimental framework using a simple vulva-development assay in the nematode C. elegans. Using this system, we evaluated a set of Ras oncogenic substitution changes at G12, G13 and Q61. We found that these variants fall into distinct groups based on phenotypic differences, sensitivity to gene dosage and inhibition of the downstream kinase MEK and their response to genetic modulators that influence Ras activity in a non-autonomous manner. Together, our results demonstrated that oncogenic C. elegans Ras variants exhibit clear distinctions in how they interface with the vulva-development network and showed that extracellular modulators yield variant-restricted effects in vivo.
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Affiliation(s)
- Haimeng Lyu
- Department of Molecular Genetics, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA
| | - Helen M. Chamberlin
- Department of Molecular Genetics, Ohio State University, 484 West 12th Avenue, Columbus, OH 43210, USA
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3
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Jeon H, Tkacik E, Eck MJ. Signaling from RAS to RAF: The Molecules and Their Mechanisms. Annu Rev Biochem 2024; 93:289-316. [PMID: 38316136 DOI: 10.1146/annurev-biochem-052521-040754] [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] [Indexed: 02/07/2024]
Abstract
RAF family protein kinases are a key node in the RAS/RAF/MAP kinase pathway, the signaling cascade that controls cellular proliferation, differentiation, and survival in response to engagement of growth factor receptors on the cell surface. Over the past few years, structural and biochemical studies have provided new understanding of RAF autoregulation, RAF activation by RAS and the SHOC2 phosphatase complex, and RAF engagement with HSP90-CDC37 chaperone complexes. These studies have important implications for pharmacologic targeting of the pathway. They reveal RAF in distinct regulatory states and show that the functional RAF switch is an integrated complex of RAF with its substrate (MEK) and a 14-3-3 dimer. Here we review these advances, placing them in the context of decades of investigation of RAF regulation. We explore the insights they provide into aberrant activation of the pathway in cancer and RASopathies (developmental syndromes caused by germline mutations in components of the pathway).
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Affiliation(s)
- Hyesung Jeon
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA;
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Emre Tkacik
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA;
- Systems, Synthetic, and Quantitative Biology PhD Program, Harvard Medical School, Boston, Massachusetts, USA
| | - Michael J Eck
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts, USA;
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
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4
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Maisonneuve P, Sahmi M, Bergeron-Labrecque F, Ma XI, Queguiner J, Arseneault G, Lefrançois M, Kurinov I, Fronzes R, Sicheri F, Therrien M. The CNK-HYP scaffolding complex promotes RAF activation by enhancing KSR-MEK interaction. Nat Struct Mol Biol 2024; 31:1028-1038. [PMID: 38388830 PMCID: PMC11257983 DOI: 10.1038/s41594-024-01233-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Accepted: 01/29/2024] [Indexed: 02/24/2024]
Abstract
The RAS-MAPK pathway regulates cell proliferation, differentiation and survival, and its dysregulation is associated with cancer development. The pathway minimally comprises the small GTPase RAS and the kinases RAF, MEK and ERK. Activation of RAF by RAS is notoriously intricate and remains only partially understood. There are three RAF isoforms in mammals (ARAF, BRAF and CRAF) and two related pseudokinases (KSR1 and KSR2). RAS-mediated activation of RAF depends on an allosteric mechanism driven by the dimerization of its kinase domain. Recent work on human RAFs showed that MEK binding to KSR1 promotes KSR1-BRAF heterodimerization, which leads to the phosphorylation of free MEK molecules by BRAF. Similar findings were made with the single Drosophila RAF homolog. Here we show that the fly scaffold proteins CNK and HYP stabilize the KSR-MEK interaction, which in turn enhances RAF-KSR heterodimerization and RAF activation. The cryogenic electron microscopy structure of the minimal KSR-MEK-CNK-HYP complex reveals a ring-like arrangement of the CNK-HYP complex allowing CNK to simultaneously engage KSR and MEK, thus stabilizing the binary interaction. Together, these results illuminate how CNK contributes to RAF activation by stimulating the allosteric function of KSR and highlight the diversity of mechanisms impacting RAF dimerization as well as the regulatory potential of the KSR-MEK interaction.
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Affiliation(s)
- Pierre Maisonneuve
- Université de Bordeaux, CNRS, Bordeaux INP, CBMN, UMR 5248, IECB, F-33600, Pessac, France.
- Center for Molecular, Cell and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.
| | - Malha Sahmi
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Quebec, Canada
| | - Fanny Bergeron-Labrecque
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Quebec, Canada
| | - Xianjie Iris Ma
- Center for Molecular, Cell and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada
| | - Juliette Queguiner
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Quebec, Canada
| | - Geneviève Arseneault
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Quebec, Canada
| | - Martin Lefrançois
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Quebec, Canada
| | - Igor Kurinov
- Department of Chemistry and Chemical Biology, Cornell University, NE-CAT, Argonne, IL, USA
| | - Rémi Fronzes
- Institut Européen de Chimie et Biologie, Université de Bordeaux-CNRS (UMR 5234), Pessac, France
| | - Frank Sicheri
- Center for Molecular, Cell and Systems Biology, Lunenfeld-Tanenbaum Research Institute, Sinai Health System, Toronto, Ontario, Canada.
- Departments of Molecular Genetics and Biochemistry, University of Toronto, Toronto, Ontario, Canada.
| | - Marc Therrien
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, Montréal, Quebec, Canada.
- Département de pathologie et biologie cellulaire, Université de Montréal, Montréal, Quebec, Canada.
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5
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Ram A, Murphy D, DeCuzzi N, Patankar M, Hu J, Pargett M, Albeck JG. A guide to ERK dynamics, part 1: mechanisms and models. Biochem J 2023; 480:1887-1907. [PMID: 38038974 PMCID: PMC10754288 DOI: 10.1042/bcj20230276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2023] [Revised: 11/02/2023] [Accepted: 11/06/2023] [Indexed: 12/02/2023]
Abstract
Extracellular signal-regulated kinase (ERK) has long been studied as a key driver of both essential cellular processes and disease. A persistent question has been how this single pathway is able to direct multiple cell behaviors, including growth, proliferation, and death. Modern biosensor studies have revealed that the temporal pattern of ERK activity is highly variable and heterogeneous, and critically, that these dynamic differences modulate cell fate. This two-part review discusses the current understanding of dynamic activity in the ERK pathway, how it regulates cellular decisions, and how these cell fates lead to tissue regulation and pathology. In part 1, we cover the optogenetic and live-cell imaging technologies that first revealed the dynamic nature of ERK, as well as current challenges in biosensor data analysis. We also discuss advances in mathematical models for the mechanisms of ERK dynamics, including receptor-level regulation, negative feedback, cooperativity, and paracrine signaling. While hurdles still remain, it is clear that higher temporal and spatial resolution provide mechanistic insights into pathway circuitry. Exciting new algorithms and advanced computational tools enable quantitative measurements of single-cell ERK activation, which in turn inform better models of pathway behavior. However, the fact that current models still cannot fully recapitulate the diversity of ERK responses calls for a deeper understanding of network structure and signal transduction in general.
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Affiliation(s)
- Abhineet Ram
- Department of Molecular and Cellular Biology, University of California, Davis, U.S.A
| | - Devan Murphy
- Department of Molecular and Cellular Biology, University of California, Davis, U.S.A
| | - Nicholaus DeCuzzi
- Department of Molecular and Cellular Biology, University of California, Davis, U.S.A
| | - Madhura Patankar
- Department of Molecular and Cellular Biology, University of California, Davis, U.S.A
| | - Jason Hu
- Department of Molecular and Cellular Biology, University of California, Davis, U.S.A
| | - Michael Pargett
- Department of Molecular and Cellular Biology, University of California, Davis, U.S.A
| | - John G. Albeck
- Department of Molecular and Cellular Biology, University of California, Davis, U.S.A
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Martin-Vega A, Cobb MH. Navigating the ERK1/2 MAPK Cascade. Biomolecules 2023; 13:1555. [PMID: 37892237 PMCID: PMC10605237 DOI: 10.3390/biom13101555] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023] Open
Abstract
The RAS-ERK pathway is a fundamental signaling cascade crucial for many biological processes including proliferation, cell cycle control, growth, and survival; common across all cell types. Notably, ERK1/2 are implicated in specific processes in a context-dependent manner as in stem cells and pancreatic β-cells. Alterations in the different components of this cascade result in dysregulation of the effector kinases ERK1/2 which communicate with hundreds of substrates. Aberrant activation of the pathway contributes to a range of disorders, including cancer. This review provides an overview of the structure, activation, regulation, and mutational frequency of the different tiers of the cascade; with a particular focus on ERK1/2. We highlight the importance of scaffold proteins that contribute to kinase localization and coordinate interaction dynamics of the kinases with substrates, activators, and inhibitors. Additionally, we explore innovative therapeutic approaches emphasizing promising avenues in this field.
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Affiliation(s)
- Ana Martin-Vega
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX 75390, USA;
| | - Melanie H. Cobb
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX 75390, USA;
- Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX 75390, USA
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7
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Chessel A, De Crozé N, Molina MD, Taberner L, Dru P, Martin L, Lepage T. RAS-independent ERK activation by constitutively active KSR3 in non-chordate metazoa. Nat Commun 2023; 14:3970. [PMID: 37407549 DOI: 10.1038/s41467-023-39606-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 06/21/2023] [Indexed: 07/07/2023] Open
Abstract
During early development of the sea urchin embryo, activation of ERK signalling in mesodermal precursors is not triggered by extracellular RTK ligands but by a cell-autonomous, RAS-independent mechanism that was not understood. We discovered that in these cells, ERK signalling is activated through the transcriptional activation of a gene encoding a protein related to Kinase Suppressor of Ras, that we named KSR3. KSR3 belongs to a family of catalytically inactive allosteric activators of RAF. Phylogenetic analysis revealed that genes encoding kinase defective KSR3 proteins are present in most non-chordate metazoa but have been lost in flies and nematodes. We show that the structure of KSR3 factors resembles that of several oncogenic human RAF mutants and that KSR3 from echinoderms, cnidarians and hemichordates activate ERK signalling independently of RAS when overexpressed in cultured cells. Finally, we used the sequence of KSR3 factors to identify activating mutations of human B-RAF. These findings reveal key functions for this family of factors as activators of RAF in RAS-independent ERK signalling in invertebrates. They have implications on the evolution of the ERK signalling pathway and suggest a mechanism for its co-option in the course of evolution.
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Affiliation(s)
- Aline Chessel
- Institut de Biologie Valrose CNRS, Université Côte d'Azur, Nice, France
| | - Noémie De Crozé
- Institut de Biologie Valrose CNRS, Université Côte d'Azur, Nice, France
| | - Maria Dolores Molina
- Department of Genetics, Microbiology and Statistics, Faculty of Biology, University of Barcelona, Barcelona, Catalonia, Spain
| | - Laura Taberner
- Institut de Biologie Valrose CNRS, Université Côte d'Azur, Nice, France
| | - Philippe Dru
- CNRS, Laboratoire de Biologie du Développement de Villefranche-sur-Mer (LBDV), Institut de la Mer de Villefranche, 181 Chemin du Lazaret, 06230, Villefranche-sur-Mer, France
| | - Luc Martin
- Institut de Biologie Valrose CNRS, Université Côte d'Azur, Nice, France
| | - Thierry Lepage
- Institut de Biologie Valrose CNRS, Université Côte d'Azur, Nice, France.
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8
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Cerón J. Caenorhabditis elegans for research on cancer hallmarks. Dis Model Mech 2023; 16:dmm050079. [PMID: 37278614 PMCID: PMC10259857 DOI: 10.1242/dmm.050079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023] Open
Abstract
After decades of research, our knowledge of the complexity of cancer mechanisms, elegantly summarized as 'hallmarks of cancer', is expanding, as are the therapeutic opportunities that this knowledge brings. However, cancer still needs intense research to diminish its tremendous impact. In this context, the use of simple model organisms such as Caenorhabditis elegans, in which the genetics of the apoptotic pathway was discovered, can facilitate the investigation of several cancer hallmarks. Amenable for genetic and drug screens, convenient for fast and efficient genome editing, and aligned with the 3Rs ('Replacement, Reduction and Refinement') principles for ethical animal research, C. elegans plays a significant role in unravelling the intricate network of cancer mechanisms and presents a promising option in clinical diagnosis and drug discovery.
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Affiliation(s)
- Julián Cerón
- Modeling Human Diseases in C. elegans Group – Genes, Disease and Therapy Program, Bellvitge Biomedical Research Institute – IDIBELL, 08908 L'Hospitalet de Llobregat, Barcelona, Spain
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9
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Udaykumar N, Zaidi MAA, Rai A, Sen J. CNKSR2, a downstream mediator of retinoic acid signaling, modulates the Ras/Raf/MEK pathway to regulate patterning and invagination of the chick forebrain roof plate. Development 2023; 150:286897. [PMID: 36734326 DOI: 10.1242/dev.200857] [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: 04/13/2022] [Accepted: 01/03/2023] [Indexed: 02/04/2023]
Abstract
During embryonic development, the forebrain roof plate undergoes invagination, leading to separation of the cerebral hemispheres. Any defects in this process, in humans, lead to middle interhemispheric holoprosencephaly (MIH-HPE). In this study, we have identified a previously unreported downstream mediator of retinoic acid (RA) signaling, CNKSR2, which is expressed in the forebrain roof plate in the chick embryo. Knockdown of CNKSR2 affects invagination, cell proliferation and patterning of the roof plate, similar to the phenotypes observed upon inhibition of RA signaling. We further demonstrate that CNKSR2 functions by modulating the Ras/Raf/MEK signaling. This appears to be crucial for patterning of the forebrain roof plate and its subsequent invagination, leading to the formation of the cerebral hemispheres. Thus, a set of novel molecular players have been identified that regulate the morphogenesis of the avian forebrain.
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Affiliation(s)
- Niveda Udaykumar
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
| | - Mohd Ali Abbas Zaidi
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
| | - Aishwarya Rai
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
| | - Jonaki Sen
- Department of Biological Sciences and Bioengineering, Indian Institute of Technology Kanpur, Kanpur 208016 Uttar Pradesh, India
- Mehta Family Center for Engineering in Medicine (MFCEM), Indian Institute of Technology Kanpur, Kanpur 208016, Uttar Pradesh, India
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10
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Singh G, Thakur N, Kumar U. RAS: Circuitry and therapeutic targeting. Cell Signal 2023; 101:110505. [PMID: 36341985 DOI: 10.1016/j.cellsig.2022.110505] [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: 08/05/2022] [Revised: 10/05/2022] [Accepted: 10/21/2022] [Indexed: 11/26/2022]
Abstract
Cancer has affected the lives of millions worldwide and is truly regarded as a devastating disease process. Despite advanced understanding of the genomic underpinning of cancer development and progression, therapeutic challenges are still persistent. Among all the human cancers, around 33% are attributed to mutations in RAS oncogene, a crucial component of the signaling pathways. With time, our understanding of RAS circuitry has improved and now the fact that it activates several downstream effectors, depending on the type and grades of cancer has been established. The circuitry is controlled via post-transcriptional mechanisms and frequent distortions in these mechanisms lead to important metabolic as well as immunological states that favor cancer cells' growth, survival, plasticity and metastasis. Therefore, understanding RAS circuitry can help researchers/clinicians to develop novel and potent therapeutics that, in turn, can save the lives of patients suffering from RAS-mutant cancers. There are many challenges presented by resistance and the potential strategies with a particular focus on novel combinations for overcoming these, that could move beyond transitory responses in the direction of treatment. Here in this review, we will look at how understanding the circuitry of RAS can be put to use in making strategies for developing therapeutics against RAS- driven malignancies.
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Affiliation(s)
- Gagandeep Singh
- Department of Biosciences (UIBT), Chandigarh University, NH-05, Ludhiana - Chandigarh State Hwy, Sahibzada Ajit Singh Nagar, Punjab 140413, India
| | - Neelam Thakur
- Department of Biosciences (UIBT), Chandigarh University, NH-05, Ludhiana - Chandigarh State Hwy, Sahibzada Ajit Singh Nagar, Punjab 140413, India; Department of Zoology, Sardar Patel University, Vallabh Government College Campus, Paddal, Kartarpur, Mandi, Himachal Pradesh 175001, India.
| | - Umesh Kumar
- School of Biosciences, Institute of Management Studies Ghaziabad (University Courses Campus), Adhyatmik Nagar, NH09, Ghaziabad, Uttar Pradesh 201015, India.
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11
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Mohapatra T, Dixit M. IQ Motif Containing GTPase Activating Proteins (IQGAPs), A-Kinase Anchoring Proteins (AKAPs) and Kinase Suppressor of Ras Proteins (KSRs) in Scaffolding Oncogenic Pathways and Their Therapeutic Potential. ACS OMEGA 2022; 7:45837-45848. [PMID: 36570181 PMCID: PMC9773950 DOI: 10.1021/acsomega.2c05505] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 11/18/2022] [Indexed: 06/17/2023]
Abstract
Scaffolding proteins colocalize interacting partners on their surface and facilitate complex formation. They have multiple domains and motifs, which provide binding sites for various molecules. This property of scaffolding proteins helps in the orderly transduction of signals. Abnormal signal transduction is frequently observed in cancers, which can also be attributed to the altered functionality of scaffolding proteins. IQ motif containing GTPase activating proteins (IQGAPs), kinase suppressor of Ras (KSR), and A-kinase anchoring proteins (AKAPs) tether oncogenic pathways RAS/RAF/MEK/ERK, PI3K/AKT, Hippo, Wnt, and CDC42/RAC to them. Scaffolding proteins are attractive drug targets as they are the controlling hub for multiple pathways and regulate crosstalk between them. The first part of this review describes the human scaffolding proteins known to play a role in oncogenesis, pathways altered by them, and the impact on oncogenic processes. The second part provides information on the therapeutic potential of scaffolding proteins and future possibilities. The information on the explored and unexplored areas of the therapeutic potential of scaffolding proteins will be equally helpful for biologists and chemists.
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Affiliation(s)
- Talina Mohapatra
- National
Institute of Science Education and Research, School of Biological Sciences, Bhubaneswar, Odisha 752050, India
- Homi
Bhabha National Institute, Training School
Complex, Anushaktinagar, Mumbai 400094, India
| | - Manjusha Dixit
- National
Institute of Science Education and Research, School of Biological Sciences, Bhubaneswar, Odisha 752050, India
- Homi
Bhabha National Institute, Training School
Complex, Anushaktinagar, Mumbai 400094, India
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12
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Corchado-Sonera M, Rambani K, Navarro K, Kladney R, Dowdle J, Leone G, Chamberlin HM. Discovery of nonautonomous modulators of activated Ras. G3 GENES|GENOMES|GENETICS 2022; 12:6656354. [PMID: 35929788 PMCID: PMC9526067 DOI: 10.1093/g3journal/jkac200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/20/2022] [Accepted: 07/18/2022] [Indexed: 11/17/2022]
Abstract
Communication between mesodermal cells and epithelial cells is fundamental to normal animal development and is frequently disrupted in cancer. However, the genes and processes that mediate this communication are incompletely understood. To identify genes that mediate this communication and alter the proliferation of cells with an oncogenic Ras genotype, we carried out a tissue-specific genome-wide RNAi screen in Caenorhabditis elegans animals bearing a let-60(n1046gf) (RasG13E) allele. The screen identifies 24 genes that, when knocked down in adjacent mesodermal tissue, suppress the increased vulval epithelial cell proliferation defect associated with let-60(n1046gf). Importantly, gene knockdown reverts the mutant animals to a wild-type phenotype. Using chimeric animals, we genetically confirm that 2 of the genes function nonautonomously to revert the let-60(n1046gf) phenotype. The effect is genotype restricted, as knockdown does not alter development in a wild type (let-60(+)) or activated EGF receptor (let-23(sa62gf)) background. Although many of the genes identified encode proteins involved in essential cellular processes, including chromatin formation, ribosome function, and mitochondrial ATP metabolism, knockdown does not alter the normal development or function of targeted mesodermal tissues, indicating that the phenotype derives from specific functions performed by these cells. We show that the genes act in a manner distinct from 2 signal ligand classes (EGF and Wnt) known to influence the development of vulval epithelial cells. Altogether, the results identify genes with a novel function in mesodermal cells required for communicating with and promoting the proliferation of adjacent epithelial cells with an activated Ras genotype.
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Affiliation(s)
| | - Komal Rambani
- Department of Cancer Biology and Genetics, Ohio State University , Columbus, OH 43210, USA
- Biomedical Sciences Graduate Program, Ohio State University , Columbus, OH 43210, USA
| | - Kristen Navarro
- Department of Molecular Genetics, Ohio State University , Columbus, OH 43210, USA
| | - Raleigh Kladney
- Department of Cancer Biology and Genetics, Ohio State University , Columbus, OH 43210, USA
| | - James Dowdle
- Department of Cancer Biology and Genetics, Ohio State University , Columbus, OH 43210, USA
| | - Gustavo Leone
- Department of Molecular Genetics, Ohio State University , Columbus, OH 43210, USA
- Department of Cancer Biology and Genetics, Ohio State University , Columbus, OH 43210, USA
| | - Helen M Chamberlin
- Department of Molecular Genetics, Ohio State University , Columbus, OH 43210, USA
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13
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Zhao J, Luo Z. Discovery of Raf Family Is a Milestone in Deciphering the Ras-Mediated Intracellular Signaling Pathway. Int J Mol Sci 2022; 23:ijms23095158. [PMID: 35563547 PMCID: PMC9101324 DOI: 10.3390/ijms23095158] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 05/02/2022] [Accepted: 05/03/2022] [Indexed: 01/27/2023] Open
Abstract
The Ras-Raf-MEK-ERK signaling pathway, the first well-established MAPK pathway, plays essential roles in cell proliferation, survival, differentiation and development. It is activated in over 40% of human cancers owing to mutations of Ras, membrane receptor tyrosine kinases and other oncogenes. The Raf family consists of three isoforms, A-Raf, B-Raf and C-Raf. Since the first discovery of a truncated mutant of C-Raf as a transforming oncogene carried by a murine retrovirus, forty years of extensive studies have provided a wealth of information on the mechanisms underlying the activation, regulation and biological functions of the Raf family. However, the mechanisms by which activation of A-Raf and C-Raf is accomplished are still not completely understood. In contrast, B-Raf can be easily activated by binding of Ras-GTP, followed by cis-autophosphorylation of the activation loop, which accounts for the fact that this isoform is frequently mutated in many cancers, especially melanoma. The identification of oncogenic B-Raf mutations has led to accelerated drug development that targets Raf signaling in cancer. However, the effort has not proved as effective as anticipated, inasmuch as the mechanism of Raf activation involves multiple steps, factors and phosphorylation of different sites, as well as complex interactions between Raf isoforms. In this review, we will focus on the physiological complexity of the regulation of Raf kinases and their connection to the ERK phosphorylation cascade and then discuss the role of Raf in tumorigenesis and the clinical application of Raf inhibitors in the treatment of cancer.
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Affiliation(s)
- Jingtong Zhao
- Queen Mary School, Nanchang University, Nanchang 330031, China;
| | - Zhijun Luo
- Queen Mary School, Nanchang University, Nanchang 330031, China;
- Provincial Key Laboratory of Tumor Pathogens and Molecular Pathology, Nanchang University, Nanchang 330031, China
- NCU-QMUL Joint Research Institute of Precision Medical Science, Nanchang 330031, China
- Correspondence:
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14
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Gao C, Wang SW, Lu JC, Chai XQ, Li YC, Zhang PF, Huang XY, Cai JB, Zheng YM, Guo XJ, Shi GM, Ke AW, Fan J. KSR2-14-3-3ζ complex serves as a biomarker and potential therapeutic target in sorafenib-resistant hepatocellular carcinoma. Biomark Res 2022; 10:25. [PMID: 35468812 PMCID: PMC9036720 DOI: 10.1186/s40364-022-00361-9] [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: 11/22/2021] [Accepted: 02/21/2022] [Indexed: 11/10/2022] Open
Abstract
Background Kinase suppressor of Ras 2 (KSR2) is a regulator of MAPK signaling that is overactivated in most hepatocellular carcinoma (HCC). We sought to determine the role of KSR2 in HCC pathogenesis. Methods We tested the level of KSR2 in HCC tissues and cell lines by tissue microarray, qPCR, and western blotting. Functionally, we determined the effects of KSR2 on the proliferation, migration, and invasion of HCC cells through colony formation assays, scratch assays, transwell migration assays, and xenograft tumor models. Co-immunoprecipitation (co-IP) experiments were used to assess the interaction of phospho-serine binding protein 14–3-3ζ and KSR2, and the effects of this interaction on growth and proliferation of human HCC cells were tested by co-overexpression and knockdown experiments. Additionally, we used flow cytometry to examine whether the KSR2 and 14–3-3ζ interaction conveys HCC resistance to sorafenib. Results KSR2 was significantly upregulated in HCC tissues and cell lines, and high KSR2 expression associated with poor prognosis in HCC patients. KSR2 knockdown significantly suppressed HCC cell proliferation, migration, and invasion in vitro and in vivo. Mechanistically, co-IP experiments identified that 14–3-3ζ complexed with KSR2, and elevated 14–3-3ζ increased KSR2 protein levels in HCC cells. Importantly, Kaplan–Meier survival analysis showed that patients with both high KSR2 and high 14–3-3ζ expression levels had the shortest survival times and poorest prognoses. Interestingly, HCC cells overexpressing both KSR2 and 14–3-3ζ, rather than either protein alone, showed hyperactivated MAPK signaling and resistance to sorafenib. Conclusions Our results provide new insights into the pro-tumorigenic role of KSR2 and its regulation of the MAPK pathway in HCC. The KSR2–14–3-3ζ interaction may be a therapeutic target to enhance the sorafenib sensitivity of HCC. Supplementary Information The online version contains supplementary material available at 10.1186/s40364-022-00361-9.
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Affiliation(s)
- Chao Gao
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Si-Wei Wang
- Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Jia-Cheng Lu
- Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Xiao-Qiang Chai
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Yuan-Cheng Li
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China.,Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Peng-Fei Zhang
- Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Xiao-Yong Huang
- Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Jia-Bin Cai
- Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Yi-Min Zheng
- Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Xiao-Jun Guo
- Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Guo-Ming Shi
- Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China
| | - Ai-Wu Ke
- Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China.
| | - Jia Fan
- Institutes of Biomedical Sciences, Fudan University, Shanghai, China. .,Key Laboratory of Carcinogenesis and Cancer Invasion, Department of Liver Surgery, Ministry of Education, Zhongshan Hospital, Liver Cancer Institute, Fudan University, Shanghai, China.
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15
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Chow A, Khan ZM, Marsiglia WM, Dar AC. Conformational control and regulation of the pseudokinase KSR via small molecule binding interactions. Methods Enzymol 2022; 667:365-402. [PMID: 35525547 PMCID: PMC9150438 DOI: 10.1016/bs.mie.2022.03.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pseudokinases often operate through functionally related enzymes and receptors. A prime example is the pseudokinase KSR (Kinase Suppressor of RAS), which can act as both an amplifier and inhibitor of members in the RAS-MAPK (Mitogen Activated Protein Kinase) signaling pathway. KSR is structurally related to the active RAF kinases over multiple domains; moreover, the pseudokinase domain of KSR forms physical and regulatory complexes with both RAF and MEK through distinct interfaces. Characterization of small molecule interactions on KSR has been used to uncover novel chemical tools and understand the mechanism of action of clinical drugs. Here, we elaborate on assays and structural methods for measuring binding at orthosteric and interfacial binding sites on KSR. These distinct small molecule pockets provide therapeutic paths for targeting KSR1 and KSR2 pseudokinases in disease, including in RAS and RAF mutant cancers.
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Affiliation(s)
- Arthur Chow
- Department of Oncological Sciences, Department of Pharmacological Sciences, The Tisch Cancer Institute, Mount Sinai Centre for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Zaigham M Khan
- Department of Oncological Sciences, Department of Pharmacological Sciences, The Tisch Cancer Institute, Mount Sinai Centre for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - William M Marsiglia
- Department of Oncological Sciences, Department of Pharmacological Sciences, The Tisch Cancer Institute, Mount Sinai Centre for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Arvin C Dar
- Department of Oncological Sciences, Department of Pharmacological Sciences, The Tisch Cancer Institute, Mount Sinai Centre for Therapeutic Discovery, Icahn School of Medicine at Mount Sinai, New York, NY, United States.
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16
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Moseley-Alldredge M, Sheoran S, Yoo H, O’Keefe C, Richmond JE, Chen L. A role for the Erk MAPK pathway in modulating SAX-7/L1CAM-dependent locomotion in Caenorhabditis elegans. Genetics 2022; 220:iyab215. [PMID: 34849872 PMCID: PMC9097276 DOI: 10.1093/genetics/iyab215] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 11/11/2021] [Indexed: 01/13/2023] Open
Abstract
L1CAMs are immunoglobulin cell adhesion molecules that function in nervous system development and function. Besides being associated with autism and schizophrenia spectrum disorders, impaired L1CAM function also underlies the X-linked L1 syndrome, which encompasses a group of neurological conditions, including spastic paraplegia and congenital hydrocephalus. Studies on vertebrate and invertebrate L1CAMs established conserved roles that include axon guidance, dendrite morphogenesis, synapse development, and maintenance of neural architecture. We previously identified a genetic interaction between the Caenorhabditis elegans L1CAM encoded by the sax-7 gene and RAB-3, a GTPase that functions in synaptic neurotransmission; rab-3; sax-7 mutant animals exhibit synthetic locomotion abnormalities and neuronal dysfunction. Here, we show that this synergism also occurs when loss of SAX-7 is combined with mutants of other genes encoding key players of the synaptic vesicle (SV) cycle. In contrast, sax-7 does not interact with genes that function in synaptogenesis. These findings suggest a postdevelopmental role for sax-7 in the regulation of synaptic activity. To assess this possibility, we conducted electrophysiological recordings and ultrastructural analyses at neuromuscular junctions; these analyses did not reveal obvious synaptic abnormalities. Lastly, based on a forward genetic screen for suppressors of the rab-3; sax-7 synthetic phenotypes, we determined that mutants in the ERK Mitogen-activated Protein Kinase (MAPK) pathway can suppress the rab-3; sax-7 locomotion defects. Moreover, we established that Erk signaling acts in a subset of cholinergic neurons in the head to promote coordinated locomotion. In combination, these results suggest a modulatory role for Erk MAPK in L1CAM-dependent locomotion in C. elegans.
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Affiliation(s)
- Melinda Moseley-Alldredge
- Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, MN 55455, USA
- Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455, USA
| | - Seema Sheoran
- Department of Biological Sciences, University of Illinois, Chicago, IL 60607, USA
| | - Hayoung Yoo
- Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Calvin O’Keefe
- Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, MN 55455, USA
| | - Janet E Richmond
- Department of Biological Sciences, University of Illinois, Chicago, IL 60607, USA
| | - Lihsia Chen
- Department of Genetics, Cell Biology & Development, University of Minnesota, Minneapolis, MN 55455, USA
- Developmental Biology Center, University of Minnesota, Minneapolis, MN 55455, USA
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17
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Pedone KH, González-Pérez V, Leopold LE, Rasmussen NR, Der CJ, Cox AD, Ahmed S, Reiner DJ. Engineering threshold-based selection systems. G3 (BETHESDA, MD.) 2021; 11:jkab234. [PMID: 34544135 PMCID: PMC8496214 DOI: 10.1093/g3journal/jkab234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/09/2021] [Accepted: 06/28/2021] [Indexed: 11/12/2022]
Abstract
Using model organisms to identify novel therapeutic targets is frequently constrained by pre-existing genetic toolkits. To expedite positive selection for identification of novel downstream effectors, we engineered conditional expression of activated CED-10/Rac to disrupt Caenorhabditis elegans embryonic morphogenesis, titrated to 100% lethality. The strategy of engineering thresholds for positive selection using experimental animals was validated with pharmacological and genetic suppression and is generalizable to diverse molecular processes and experimental systems.
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Affiliation(s)
- Katherine H Pedone
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Vanessa González-Pérez
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Luciana E Leopold
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Neal R Rasmussen
- Institute of Biosciences and Technology, College of Medicine, Texas A&M Health Science Center, Houston, TX 77030, USA
| | - Channing J Der
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Adrienne D Cox
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Shawn Ahmed
- Curriculum in Genetics and Molecular Biology, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Biology, University of North Carolina, Chapel Hill, NC 27599, USA
| | - David J Reiner
- Lineberger Comprehensive Cancer Center, University of North Carolina, Chapel Hill, NC 27599, USA
- Institute of Biosciences and Technology, College of Medicine, Texas A&M Health Science Center, Houston, TX 77030, USA
- Department of Pharmacology, University of North Carolina, Chapel Hill, NC 27599, USA
- Department of Radiation Oncology, University of North Carolina, Chapel Hill, NC 27599, USA
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18
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Kondo Y, Paul JW, Subramaniam S, Kuriyan J. New insights into Raf regulation from structural analyses. Curr Opin Struct Biol 2021; 71:223-231. [PMID: 34454301 DOI: 10.1016/j.sbi.2021.07.005] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/06/2021] [Accepted: 07/10/2021] [Indexed: 01/07/2023]
Abstract
BRAF is a highly regulated protein kinase that controls cell fate in animal cells. Recent structural analyses have revealed how active and inactive forms of BRAF bind to dimers of the scaffold protein 14-3-3. Inactive BRAF binds to 14-3-3 as a monomer and is held in an inactive conformation by interactions with ATP and the substrate kinase MEK, a striking example of enzyme inhibition by substrate binding. A change in the phosphorylation state of BRAF shifts the stoichiometry of the BRAF:14-3-3 complex from 1:2 to 2:2, resulting in stabilization of the active dimeric form of the kinase. These new findings uncover unexpected features of the regulatory mechanisms underlying Raf biology and help explain the paradoxical activation of Raf by small-molecule inhibitors.
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Affiliation(s)
- Yasushi Kondo
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | - Joseph W Paul
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA
| | | | - John Kuriyan
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, 94720, USA; California Institute for Quantitative Biosciences, University of California, Berkeley, CA, 94720, USA; Howard Hughes Medical Institute, University of California, Berkeley, CA, 94720, USA; Department of Chemistry, University of California, Berkeley, CA, 94720, USA; Division of Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA, 94720, USA.
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19
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Kropp PA, Bauer R, Zafra I, Graham C, Golden A. Caenorhabditis elegans for rare disease modeling and drug discovery: strategies and strengths. Dis Model Mech 2021; 14:dmm049010. [PMID: 34370008 PMCID: PMC8380043 DOI: 10.1242/dmm.049010] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Although nearly 10% of Americans suffer from a rare disease, clinical progress in individual rare diseases is severely compromised by lack of attention and research resources compared to common diseases. It is thus imperative to investigate these diseases at their most basic level to build a foundation and provide the opportunity for understanding their mechanisms and phenotypes, as well as potential treatments. One strategy for effectively and efficiently studying rare diseases is using genetically tractable organisms to model the disease and learn about the essential cellular processes affected. Beyond investigating dysfunctional cellular processes, modeling rare diseases in simple organisms presents the opportunity to screen for pharmacological or genetic factors capable of ameliorating disease phenotypes. Among the small model organisms that excel in rare disease modeling is the nematode Caenorhabditis elegans. With a staggering breadth of research tools, C. elegans provides an ideal system in which to study human disease. Molecular and cellular processes can be easily elucidated, assayed and altered in ways that can be directly translated to humans. When paired with other model organisms and collaborative efforts with clinicians, the power of these C. elegans studies cannot be overstated. This Review highlights studies that have used C. elegans in diverse ways to understand rare diseases and aid in the development of treatments. With continuing and advancing technologies, the capabilities of this small round worm will continue to yield meaningful and clinically relevant information for human health.
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Affiliation(s)
| | | | | | | | - Andy Golden
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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20
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Nishiyama K, Maekawa M, Nakagita T, Nakayama J, Kiyoi T, Chosei M, Murakami A, Kamei Y, Takeda H, Takada Y, Higashiyama S. CNKSR1 serves as a scaffold to activate an EGFR phosphatase via exclusive interaction with RhoB-GTP. Life Sci Alliance 2021; 4:4/9/e202101095. [PMID: 34187934 PMCID: PMC8321701 DOI: 10.26508/lsa.202101095] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/17/2021] [Accepted: 06/21/2021] [Indexed: 12/15/2022] Open
Abstract
CNKSR1 functions as a scaffold protein for activation of an EGFR phosphatase, PTPRH, at the plasma membrane through the exclusive interaction with RhoB-GTP which is constitutively degraded by the CUL3/KCTD10 E3 complex. Epidermal growth factor receptor (EGFR) and human EGFR 2 (HER2) phosphorylation drives HER2-positive breast cancer cell proliferation. Enforced activation of phosphatases for those receptors could be a therapeutic option for HER2-positive breast cancers. Here, we report that degradation of an endosomal small GTPase, RhoB, by the ubiquitin ligase complex cullin-3 (CUL3)/KCTD10 is essential for both EGFR and HER2 phosphorylation in HER2-positive breast cancer cells. Using human protein arrays produced in a wheat cell-free protein synthesis system, RhoB-GTP, and protein tyrosine phosphatase receptor type H (PTPRH) were identified as interacting proteins of connector enhancer of kinase suppressor of Ras1 (CNKSR1). Mechanistically, constitutive degradation of RhoB, which is mediated by the CUL3/KCTD10 E3 complex, enabled CNKSR1 to interact with PTPRH at the plasma membrane resulting in inactivation of EGFR phosphatase activity. Depletion of CUL3 or KCTD10 led to the accumulation of RhoB-GTP at the plasma membrane followed by its interaction with CNKSR1, which released activated PTPRH from CNKSR1. This study suggests a mechanism of PTPRH activation through the exclusive binding of RhoB-GTP to CNKSR1.
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Affiliation(s)
- Kanako Nishiyama
- Department of Hepato-Biliary-Pancreatic Surgery and Breast Surgery, Ehime University Graduate School of Medicine, Toon, Japan.,Department of Biochemistry and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Japan
| | - Masashi Maekawa
- Department of Biochemistry and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Japan .,Division of Cell Growth and Tumor Regulation, Proteo-Science Center, Ehime University, Toon, Japan
| | - Tomoya Nakagita
- Division of Proteo-Drug-Discovery Sciences, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Jun Nakayama
- Division of Cellular Signaling, National Cancer Center Research Institute, Chuo-ku, Japan
| | - Takeshi Kiyoi
- Division of Analytical Bio-medicine, Advanced Research Support Center, Ehime University, Toon, Japan
| | - Mami Chosei
- Division of Cell Growth and Tumor Regulation, Proteo-Science Center, Ehime University, Toon, Japan
| | - Akari Murakami
- Department of Hepato-Biliary-Pancreatic Surgery and Breast Surgery, Ehime University Graduate School of Medicine, Toon, Japan
| | - Yoshiaki Kamei
- Department of Hepato-Biliary-Pancreatic Surgery and Breast Surgery, Ehime University Graduate School of Medicine, Toon, Japan
| | - Hiroyuki Takeda
- Division of Proteo-Drug-Discovery Sciences, Proteo-Science Center, Ehime University, Matsuyama, Japan
| | - Yasutsugu Takada
- Department of Hepato-Biliary-Pancreatic Surgery and Breast Surgery, Ehime University Graduate School of Medicine, Toon, Japan
| | - Shigeki Higashiyama
- Department of Biochemistry and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Japan .,Division of Cell Growth and Tumor Regulation, Proteo-Science Center, Ehime University, Toon, Japan.,Department of Molecular and Cellular Biology, Osaka International Cancer Institute, Chuo-ku, Osaka, Japan
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21
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Ullah R, Yin Q, Snell AH, Wan L. RAF-MEK-ERK pathway in cancer evolution and treatment. Semin Cancer Biol 2021; 85:123-154. [PMID: 33992782 DOI: 10.1016/j.semcancer.2021.05.010] [Citation(s) in RCA: 139] [Impact Index Per Article: 46.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/03/2021] [Accepted: 05/06/2021] [Indexed: 12/13/2022]
Abstract
The RAF-MEK-ERK signaling cascade is a well-characterized MAPK pathway involved in cell proliferation and survival. The three-layered MAPK signaling cascade is initiated upon RTK and RAS activation. Three RAF isoforms ARAF, BRAF and CRAF, and their downstream MEK1/2 and ERK1/2 kinases constitute a coherently orchestrated signaling module that directs a range of physiological functions. Genetic alterations in this pathway are among the most prevalent in human cancers, which consist of numerous hot-spot mutations such as BRAFV600E. Oncogenic mutations in this pathway often override otherwise tightly regulated checkpoints to open the door for uncontrolled cell growth and neoplasia. The crosstalk between the RAF-MEK-ERK axis and other signaling pathways further extends the proliferative potential of this pathway in human cancers. In this review, we summarize the molecular architecture and physiological functions of the RAF-MEK-ERK pathway with emphasis on its dysregulations in human cancers, as well as the efforts made to target the RAF-MEK-ERK module using small molecule inhibitors.
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Affiliation(s)
- Rahim Ullah
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA
| | - Qing Yin
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA
| | - Aidan H Snell
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA
| | - Lixin Wan
- Department of Molecular Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA; Department of Cutaneous Oncology, H. Lee Moffitt Cancer Center and Research Institute, Tampa, FL, 33612, USA.
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22
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Moon H, Ro SW. Ras Mitogen-activated Protein Kinase Signaling and Kinase Suppressor of Ras as Therapeutic Targets for Hepatocellular Carcinoma. JOURNAL OF LIVER CANCER 2021; 21:1-11. [PMID: 37384270 PMCID: PMC10035721 DOI: 10.17998/jlc.21.1.1] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/27/2020] [Accepted: 09/01/2020] [Indexed: 06/30/2023]
Abstract
Hepatocellular carcinoma (HCC) is a high incidence cancer and a major health concern worldwide. Among the many molecular signaling pathways that are dysregulated in HCC, the Ras mitogen-activated protein kinase (Ras/Raf/MAPK) signaling pathway has gained renewed attention from basic and clinical researchers. Mutations in Ras and Raf genes which are known to activate the Ras/Raf/MAPK signaling pathway have been infrequently detected in human HCC; however, the Ras/Raf/MAPK signaling pathway is activated in more than 50% of HCC cases, suggesting an alternative mechanism for the activation of the signaling pathway. Kinase suppressor of Ras acts as a molecular scaffold for facilitating the assembly of Ras/Raf/MAPK signaling pathway components and has been implicated in the regulation of this signaling pathway. In this review, we provide important insights into the cellular and molecular mechanisms involved in the activation of the Ras/Raf/MAPK signaling pathway and discuss potential therapeutic strategies for HCC.
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Affiliation(s)
- Hyuk Moon
- Department of Genetic Engineering, Kyung Hee University College of Life Sciences, Yongin, Korea
| | - Simon Weonsang Ro
- Department of Genetic Engineering, Kyung Hee University College of Life Sciences, Yongin, Korea
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23
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Sawyer JK, Kabiri Z, Montague RA, Allen SR, Stewart R, Paramore SV, Cohen E, Zaribafzadeh H, Counter CM, Fox DT. Exploiting codon usage identifies intensity-specific modifiers of Ras/MAPK signaling in vivo. PLoS Genet 2020; 16:e1009228. [PMID: 33296356 PMCID: PMC7752094 DOI: 10.1371/journal.pgen.1009228] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 12/21/2020] [Accepted: 10/27/2020] [Indexed: 01/05/2023] Open
Abstract
Signal transduction pathways are intricately fine-tuned to accomplish diverse biological processes. An example is the conserved Ras/mitogen-activated-protein-kinase (MAPK) pathway, which exhibits context-dependent signaling output dynamics and regulation. Here, by altering codon usage as a novel platform to control signaling output, we screened the Drosophila genome for modifiers specific to either weak or strong Ras-driven eye phenotypes. Our screen enriched for regions of the genome not previously connected with Ras phenotypic modification. We mapped the underlying gene from one modifier to the ribosomal gene RpS21. In multiple contexts, we show that RpS21 preferentially influences weak Ras/MAPK signaling outputs. These data show that codon usage manipulation can identify new, output-specific signaling regulators, and identify RpS21 as an in vivo Ras/MAPK phenotypic regulator. Cellular communication is critical in controlling the growth of organs and must be carefully regulated to prevent disease. The Ras signaling pathway is frequently used for cellular communication of tissue growth regulation but can operate at different signaling strengths. Here, we used a novel strategy to identify genes that specifically tune weak or strong Ras signaling states. We find that the gene RpS21 preferentially tunes weak Ras signaling states.
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Affiliation(s)
- Jessica K. Sawyer
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Zahra Kabiri
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Ruth A. Montague
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Scott R. Allen
- Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Rebeccah Stewart
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Sarah V. Paramore
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Erez Cohen
- Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Hamed Zaribafzadeh
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
| | - Christopher M. Counter
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
- Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
- * E-mail: (CMC); (DTF)
| | - Donald T. Fox
- Department of Pharmacology & Cancer Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
- Department of Cell Biology, Duke University School of Medicine, Durham, North Carolina, United States of America
- Duke Cancer Institute, Duke University School of Medicine, Durham, North Carolina, United States of America
- * E-mail: (CMC); (DTF)
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24
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Li D, Yuan Y, Wang D. Regulation of response to nanopolystyrene by intestinal microRNA mir-35 in nematode Caenorhabditis elegans. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 736:139677. [PMID: 32473456 DOI: 10.1016/j.scitotenv.2020.139677] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 05/22/2020] [Accepted: 05/22/2020] [Indexed: 06/11/2023]
Abstract
In nematode Caenorhabditis elegans, mir-35, a microRNA molecule, was involved in the control of response to nanopolystyrene. Exposure to nanopolystyrene (100 nm) could significantly increase the mir-35 expression. However, the underlying mechanism for this role of mir-35 remains largely unclear. Based on analysis of expression levels, phenotypes, and genetic interactions, we examined the underlying mechanism of intestinal mir-35 in regulating the response to nanopolystyrene. In nematodes, we here found that mir-35 acted in the intestine to regulate the response to nanopolystyrene. In the intestine, NDK-1, homolog of NM23-H1, was identified as the direct target of mir-35, suggesting that intestinal mir-35 regulated the response to nanopolystyrene by suppressing the NDK-1 function. Moreover, intestinal NDK-1 could regulate the response to nanopolystyrene by suppressing the function of FOXO transcriptional factor DAF-16 in the insulin signaling pathway. In nanopolystyrene exposed nematodes, kinase suppressors of Ras (KSR-1 and KSR-2) were further identified as downstream targets of intestinal NDK-1. Moreover, DAF-16 functioned with KSR-1 or KSR-2 in different pathways to regulate the response to nanopolystyrene. Therefore, we have identified an intestinal signaling cascade of mir-35-NDK-1-DAF-16/KSR-1/2 to be required for the control of response to nanopolystyrene. Our results provided an important molecular basis for intestinal response to nanopolystyrene in nematodes.
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Affiliation(s)
- Dan Li
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
| | - Yujie Yuan
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China
| | - Dayong Wang
- Key Laboratory of Environmental Medicine Engineering in Ministry of Education, Medical School, Southeast University, Nanjing 210009, China; Shenzhen Ruipuxun Academy for Stem Cell & Regenerative Medicine, Shenzhen 518122, China; Guangdong Provincial Key Laboratory of Environmental Pollution and Health, School of Environment, Jinan University, Guangzhou 510632, China.
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Harnessing the power of genetics: fast forward genetics in Caenorhabditis elegans. Mol Genet Genomics 2020; 296:1-20. [PMID: 32888055 DOI: 10.1007/s00438-020-01721-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 08/27/2020] [Indexed: 12/23/2022]
Abstract
Forward genetics is a powerful tool to unravel molecular mechanisms of diverse biological processes. The success of genetic screens primarily relies on the ease of genetic manipulation of an organism and the availability of a plethora of genetic tools. The roundworm Caenorhabditis elegans has been one of the favorite models for genetic studies due to its hermaphroditic lifestyle, ease of maintenance, and availability of various genetic manipulation tools. The strength of C. elegans genetics is highlighted by the leading role of this organism in the discovery of several conserved biological processes. In this review, the principles and strategies for forward genetics in C. elegans are discussed. Further, the recent advancements that have drastically accelerated the otherwise time-consuming process of mutation identification, making forward genetic screens a method of choice for understanding biological functions, are discussed. The emphasis of the review has been on providing practical and conceptual pointers for designing genetic screens that will identify mutations, specifically disrupting the biological processes of interest.
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26
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Kramer-Drauberg M, Liu JL, Desjardins D, Wang Y, Branicky R, Hekimi S. ROS regulation of RAS and vulva development in Caenorhabditis elegans. PLoS Genet 2020; 16:e1008838. [PMID: 32544191 PMCID: PMC7319342 DOI: 10.1371/journal.pgen.1008838] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2019] [Revised: 06/26/2020] [Accepted: 05/07/2020] [Indexed: 12/28/2022] Open
Abstract
Reactive oxygen species (ROS) are signalling molecules whose study in intact organisms has been hampered by their potential toxicity. This has prevented a full understanding of their role in organismal processes such as development, aging and disease. In Caenorhabditis elegans, the development of the vulva is regulated by a signalling cascade that includes LET-60ras (homologue of mammalian Ras), MPK-1 (ERK1/2) and LIN-1 (an ETS transcription factor). We show that both mitochondrial and cytoplasmic ROS act on a gain-of-function (gf) mutant of the LET-60ras protein through a redox-sensitive cysteine (C118) previously identified in mammals. We show that the prooxidant paraquat as well as isp-1, nuo-6 and sod-2 mutants, which increase mitochondrial ROS, inhibit the activity of LET-60rasgf on vulval development. In contrast, the antioxidant NAC and loss of sod-1, both of which decrease cytoplasmic H202, enhance the activity of LET-60rasgf. CRISPR replacement of C118 with a non-oxidizable serine (C118S) stimulates LET-60rasgf activity, whereas replacement of C118 with aspartate (C118D), which mimics a strongly oxidised cysteine, inhibits LET-60rasgf. These data strongly suggest that C118 is oxidized by cytoplasmic H202 generated from dismutation of mitochondrial and/or cytoplasmic superoxide, and that this oxidation inhibits LET-60ras. This contrasts with results in cultured mammalian cells where it is mostly nitric oxide, which is not found in worms, that oxidizes C118 and activates Ras. Interestingly, PQ, NAC and the C118S mutation do not act on the phosphorylation of MPK-1, suggesting that oxidation of LET-60ras acts on an as yet uncharacterized MPK-1-independent pathway. We also show that elevated cytoplasmic superoxide promotes vulva formation independently of C118 of LET-60ras and downstream of LIN-1. Finally, we uncover a role for the NADPH oxidases (BLI-3 and DUOX-2) and their redox-sensitive activator CED-10rac in stimulating vulva development. Thus, there are at least three genetically separable pathways by which ROS regulates vulval development.
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Affiliation(s)
| | - Ju-Ling Liu
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - David Desjardins
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Ying Wang
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Robyn Branicky
- Department of Biology, McGill University, Montreal, Quebec, Canada
| | - Siegfried Hekimi
- Department of Biology, McGill University, Montreal, Quebec, Canada
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27
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Degirmenci U, Wang M, Hu J. Targeting Aberrant RAS/RAF/MEK/ERK Signaling for Cancer Therapy. Cells 2020; 9:E198. [PMID: 31941155 PMCID: PMC7017232 DOI: 10.3390/cells9010198] [Citation(s) in RCA: 296] [Impact Index Per Article: 74.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 12/29/2019] [Accepted: 01/10/2020] [Indexed: 12/13/2022] Open
Abstract
The RAS/RAF/MEK/ERK (MAPK) signaling cascade is essential for cell inter- and intra-cellular communication, which regulates fundamental cell functions such as growth, survival, and differentiation. The MAPK pathway also integrates signals from complex intracellular networks in performing cellular functions. Despite the initial discovery of the core elements of the MAPK pathways nearly four decades ago, additional findings continue to make a thorough understanding of the molecular mechanisms involved in the regulation of this pathway challenging. Considerable effort has been focused on the regulation of RAF, especially after the discovery of drug resistance and paradoxical activation upon inhibitor binding to the kinase. RAF activity is regulated by phosphorylation and conformation-dependent regulation, including auto-inhibition and dimerization. In this review, we summarize the recent major findings in the study of the RAS/RAF/MEK/ERK signaling cascade, particularly with respect to the impact on clinical cancer therapy.
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Affiliation(s)
- Ufuk Degirmenci
- Division of Cellular and Molecular Research, National Cancer Centre Singapore, 11 Hospital Crescent, Singapore 169610, Singapore
| | - Mei Wang
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
| | - Jiancheng Hu
- Division of Cellular and Molecular Research, National Cancer Centre Singapore, 11 Hospital Crescent, Singapore 169610, Singapore
- Cancer and Stem Cell Biology Program, Duke-NUS Medical School, 8 College Road, Singapore 169857, Singapore
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28
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Gimple RC, Wang X. RAS: Striking at the Core of the Oncogenic Circuitry. Front Oncol 2019; 9:965. [PMID: 31681559 PMCID: PMC6798062 DOI: 10.3389/fonc.2019.00965] [Citation(s) in RCA: 97] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 09/11/2019] [Indexed: 12/15/2022] Open
Abstract
Cancer is a devastating disease process that touches the lives of millions worldwide. Despite advances in our understanding of the genomic architecture of cancers and the mechanisms that underlie cancer development, a great therapeutic challenge remains. Here, we revisit the birthplace of cancer biology and review how one of the first discovered oncogenes, RAS, drives cancers in new and unexpected ways. As our understanding of oncogenic signaling has evolved, it is clear that RAS signaling is not homogenous, but activates distinct downstream effectors in different cancer types and grades. RAS signaling is tightly controlled through a series of post-transcriptional mechanisms, which are frequently distorted in the context of cancer, and establish key metabolic and immunologic states that support cancer growth, migration, survival, metastasis, and plasticity. While targeting RAS has been fiercely pursued for decades, new strategies have recently emerged with the potential for therapeutic efficacy. Thus, understanding the complexities of RAS biology may translate into improved therapies for patients with RAS-driven cancers.
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Affiliation(s)
- Ryan C Gimple
- Division of Regenerative Medicine, Department of Medicine, University of California, San Diego, San Diego, CA, United States.,Department of Pathology, Case Western University, Cleveland, OH, United States
| | - Xiuxing Wang
- Key Laboratory of Antibody Technique of Ministry of Health, Nanjing Medical University, Nanjing, China
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29
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Terrell EM, Morrison DK. Ras-Mediated Activation of the Raf Family Kinases. Cold Spring Harb Perspect Med 2019; 9:cshperspect.a033746. [PMID: 29358316 DOI: 10.1101/cshperspect.a033746] [Citation(s) in RCA: 103] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The extracellular signal-regulated kinase (ERK) cascade comprised of the Raf, MEK, and ERK protein kinases constitutes a key effector cascade used by the Ras GTPases to relay signals regulating cell growth, survival, proliferation, and differentiation. Of the ERK cascade components, the regulation of the Raf kinases is by far the most complex, involving changes in subcellular localization, protein and lipid interactions, as well as alterations in the Raf phosphorylation state. The Raf kinases interact directly with active, membrane-localized Ras, and this interaction is often the first step in the Raf activation process, which ultimately results in ERK activation and the downstream phosphorylation of cellular targets that will specify a particular biological response. Here, we will examine our current understanding of how Ras promotes Raf activation, focusing on the molecular mechanisms that contribute to the Raf activation/inactivation cycle.
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Affiliation(s)
- Elizabeth M Terrell
- Laboratory of Cell and Developmental Signaling, NCI-Frederick, Frederick, Maryland 21702
| | - Deborah K Morrison
- Laboratory of Cell and Developmental Signaling, NCI-Frederick, Frederick, Maryland 21702
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Shin H, Reiner DJ. The Signaling Network Controlling C. elegans Vulval Cell Fate Patterning. J Dev Biol 2018; 6:E30. [PMID: 30544993 PMCID: PMC6316802 DOI: 10.3390/jdb6040030] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Revised: 12/08/2018] [Accepted: 12/10/2018] [Indexed: 12/17/2022] Open
Abstract
EGF, emitted by the Anchor Cell, patterns six equipotent C. elegans vulval precursor cells to assume a precise array of three cell fates with high fidelity. A group of core and modulatory signaling cascades forms a signaling network that demonstrates plasticity during the transition from naïve to terminally differentiated cells. In this review, we summarize the history of classical developmental manipulations and molecular genetics experiments that led to our understanding of the signals governing this process, and discuss principles of signal transduction and developmental biology that have emerged from these studies.
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Affiliation(s)
- Hanna Shin
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA.
| | - David J Reiner
- Institute of Biosciences and Technology, Texas A&M Health Science Center, Houston, TX 77030, USA.
- College of Medicine, Texas A & M University, Houston, TX 77030, USA.
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31
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Mugabo Y, Lim GE. Scaffold Proteins: From Coordinating Signaling Pathways to Metabolic Regulation. Endocrinology 2018; 159:3615-3630. [PMID: 30204866 PMCID: PMC6180900 DOI: 10.1210/en.2018-00705] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 09/05/2018] [Indexed: 01/13/2023]
Abstract
Among their pleiotropic functions, scaffold proteins are required for the accurate coordination of signaling pathways. It has only been within the past 10 years that their roles in glucose homeostasis and metabolism have emerged. It is well appreciated that changes in the expression or function of signaling effectors, such as receptors or kinases, can influence the development of chronic diseases such as diabetes and obesity. However, little is known regarding whether scaffolds have similar roles in the pathogenesis of metabolic diseases. In general, scaffolds are often underappreciated in the context of metabolism or metabolic diseases. In the present review, we discuss various scaffold proteins and their involvement in signaling pathways related to metabolism and metabolic diseases. The aims of the present review were to highlight the importance of scaffold proteins and to raise awareness of their physiological contributions. A thorough understanding of how scaffolds influence metabolism could aid in the discovery of novel therapeutic approaches to treat chronic conditions, such as diabetes, obesity, and cardiovascular disease, for which the incidence of all continue to increase at alarming rates.
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Affiliation(s)
- Yves Mugabo
- Cardiometabolic Axis, Centre de Recherche de Centre Hospitalier de l’Université de Montréal, Montreal, Quebec, Canada
- Montréal Diabetes Research Centre, Montreal, Quebec, Canada
- Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
| | - Gareth E Lim
- Cardiometabolic Axis, Centre de Recherche de Centre Hospitalier de l’Université de Montréal, Montreal, Quebec, Canada
- Montréal Diabetes Research Centre, Montreal, Quebec, Canada
- Department of Medicine, Université de Montréal, Montreal, Quebec, Canada
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32
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Hymowitz SG, Malek S. Targeting the MAPK Pathway in RAS Mutant Cancers. Cold Spring Harb Perspect Med 2018; 8:cshperspect.a031492. [PMID: 29440321 DOI: 10.1101/cshperspect.a031492] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Despite decades of extensive drug discovery efforts, there are currently no targeted therapies approved to treat KRAS mutant cancers. In this review, we highlight the challenges and opportunities in targeting KRAS mutant tumors through inhibition of mitogen-activated protein kinase (MAPK) signaling with conformation-specific kinase inhibitors. Through structural analysis and mechanistic studies with BRAF and mitogen-activated protein kinase (MEK) inhibitors, we describe how kinase-dependent and -independent functions of MAPK signaling components regulate KRAS-driven tumorigenesis and how these insights can be used to treat RAS mutant cancers with small molecule kinase inhibitors.
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Affiliation(s)
- Sarah G Hymowitz
- Department of Structural Biology, Genentech Inc., South San Francisco, California 94080
| | - Shiva Malek
- Department of Discovery Oncology, Genentech Inc., South San Francisco, California 94080
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33
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Structural snapshots of RAF kinase interactions. Biochem Soc Trans 2018; 46:1393-1406. [PMID: 30381334 DOI: 10.1042/bst20170528] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2018] [Revised: 07/25/2018] [Accepted: 07/30/2018] [Indexed: 02/07/2023]
Abstract
RAF (rapidly accelerated fibrosarcoma) Ser/Thr kinases (ARAF, BRAF, and CRAF) link the RAS (rat sarcoma) protein family with the MAPK (mitogen-activated protein kinase) pathway and control cell growth, differentiation, development, aging, and tumorigenesis. Their activity is specifically modulated by protein-protein interactions, post-translational modifications, and conformational changes in specific spatiotemporal patterns via various upstream regulators, including the kinases, phosphatase, GTPases, and scaffold and modulator proteins. Dephosphorylation of Ser-259 (CRAF numbering) and dissociation of 14-3-3 release the RAF regulatory domains RAS-binding domain and cysteine-rich domain for interaction with RAS-GTP and membrane lipids. This, in turn, results in RAF phosphorylation at Ser-621 and 14-3-3 reassociation, followed by its dimerization and ultimately substrate binding and phosphorylation. This review focuses on structural understanding of how distinct binding partners trigger a cascade of molecular events that induces RAF kinase activation.
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Bai Y, Han G, Guo K, Yu L, Du X, Xu Y. Effect of lentiviral vector-mediated KSR1 gene silencing on the proliferation of renal tubular epithelial cells and expression of inflammatory factors in a rat model of ischemia/reperfusion injury. Acta Biochim Biophys Sin (Shanghai) 2018; 50:807-816. [PMID: 30020400 DOI: 10.1093/abbs/gmy071] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 05/31/2018] [Indexed: 11/14/2022] Open
Abstract
Renal ischemia/reperfusion (I/R) is a common cause of acute renal failure in many clinical settings. Our study aimed to elucidate the role of lentiviral vector-mediated KSR1 gene silencing in inflammatory factor expression and proliferation of renal tubular epithelial cells (RTECs) in a rat model of I/R injury. Male Sprague-Dawley (SD) rats were used for I/R model establishment and subject to different treatments, followed by the measurement of neurological severity score (NSS), tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β, 47-kDa heat-shock protein (HSP47), KSR1, and factors related to the Ras/MAPK pathway, as well as cell apoptosis. As compared with the blank group, the neurologic impairment induced by I/R in the siKSR1, U0126, and siKSR1 + U0126 groups was alleviated. Compared with the control group, the other five groups showed increased levels of TNF-α, IL-6, IL-1β, HSP47, N-ras, Raf-1, c-fos, TNF-α, IL-6, p38 MAPK, and cell apoptosis, accompanied by a declined mRNA and protein level of Bcl-2. As compared with the blank and NC groups, the siKSR1, U0126, and siKSR1 + U0126 groups showed decreased levels of TNF-α, IL-6, IL-1β, HSP47, N-ras, Raf-1, c-fos, TNF-α, IL-6, p38 MAPK, cleaved caspase-3, cleaved caspase-9, p53, and cell apoptosis, accompanied by an increased mRNA and protein level of Bcl-2. Our findings demonstrated that KSR1 gene silencing might inhibit the expression of inflammatory factors in RTECs and promote their proliferation by inactivating the Ras/MAPK pathway in the rat model of I/R injury.
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Affiliation(s)
- Yang Bai
- Department of Ultrasound, The First Hospital of Jilin University, Changchun, China
| | - Guanghong Han
- Department of Oral Geriatrics, School and Hospital of Stomatology, Jilin University, Changchun, China
| | - Kaimin Guo
- Department of Andrology, The First Hospital of Jilin University, Changchun, China
| | - Lili Yu
- Social Development Bureau, Changchun Jingyue High-Tech Industrial Development Zone Management Committee, Changchun, China
| | - Xiadong Du
- Department of Ultrasound, The First Hospital of Jilin University, Changchun, China
| | - Ying Xu
- Department of Nephrology, The First Hospital of Jilin University, Changchun, China
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Coleman B, Topalidou I, Ailion M. Modulation of Gq-Rho Signaling by the ERK MAPK Pathway Controls Locomotion in Caenorhabditis elegans. Genetics 2018; 209:523-535. [PMID: 29615470 PMCID: PMC5972424 DOI: 10.1534/genetics.118.300977] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 03/29/2018] [Indexed: 12/17/2022] Open
Abstract
The heterotrimeric G protein Gq regulates neuronal activity through distinct downstream effector pathways. In addition to the canonical Gq effector phospholipase Cβ, the small GTPase Rho was recently identified as a conserved effector of Gq. To identify additional molecules important for Gq signaling in neurons, we performed a forward genetic screen in the nematode Caenorhabditis elegans for suppressors of the hyperactivity and exaggerated waveform of an activated Gq mutant. We isolated two mutations affecting the MAP kinase scaffold protein KSR-1 and found that KSR-1 modulates locomotion downstream of, or in parallel to, the Gq-Rho pathway. Through epistasis experiments, we found that the core ERK MAPK cascade is required for Gq-Rho regulation of locomotion, but that the canonical ERK activator LET-60/Ras may not be required. Through neuron-specific rescue experiments, we found that the ERK pathway functions in head acetylcholine neurons to control Gq-dependent locomotion. Additionally, expression of activated LIN-45/Raf in head acetylcholine neurons is sufficient to cause an exaggerated waveform phenotype and hypersensitivity to the acetylcholinesterase inhibitor aldicarb, similar to an activated Gq mutant. Taken together, our results suggest that the ERK MAPK pathway modulates the output of Gq-Rho signaling to control locomotion behavior in C. elegans.
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Affiliation(s)
- Brantley Coleman
- Department of Biochemistry, University of Washington, Seattle, Washington 98195
| | - Irini Topalidou
- Department of Biochemistry, University of Washington, Seattle, Washington 98195
| | - Michael Ailion
- Department of Biochemistry, University of Washington, Seattle, Washington 98195
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Germino EA, Miller JP, Diehl L, Swanson CJ, Durinck S, Modrusan Z, Miner JH, Shaw AS. Homozygous KSR1 deletion attenuates morbidity but does not prevent tumor development in a mouse model of RAS-driven pancreatic cancer. PLoS One 2018; 13:e0194998. [PMID: 29596465 PMCID: PMC5875795 DOI: 10.1371/journal.pone.0194998] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 03/14/2018] [Indexed: 01/04/2023] Open
Abstract
Given the frequency with which MAP kinase signaling is dysregulated in cancer, much effort has been focused on inhibiting RAS signaling for therapeutic benefit. KSR1, a pseudokinase that interacts with RAF, is a potential target; it was originally cloned in screens for suppressors of constitutively active RAS, and its deletion prevents RAS-mediated transformation of mouse embryonic fibroblasts. In this work, we used a genetically engineered mouse model of pancreatic cancer to assess whether KSR1 deletion would influence tumor development in the setting of oncogenic RAS. We found that Ksr1-/- mice on this background had a modest but significant improvement in all-cause morbidity compared to Ksr1+/+ and Ksr1+/- cohorts. Ksr1-/- mice, however, still developed tumors, and precursor pancreatic intraepithelial neoplastic (PanIN) lesions were detected within a similar timeframe compared to Ksr1+/+ mice. No significant differences in pERK expression or in proliferation were noted. RNA sequencing also did not reveal any unique genetic signature in Ksr1-/- tumors. Further studies will be needed to determine whether and in what settings KSR inhibition may be clinically useful.
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Affiliation(s)
- Elizabeth A. Germino
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Research Biology, Genentech, South San Francisco, California, United States of America
| | - Joseph P. Miller
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Lauri Diehl
- Department of Pathology, Genentech, South San Francisco, California, United States of America
| | - Carter J. Swanson
- Department of Research Biology, Genentech, South San Francisco, California, United States of America
| | - Steffen Durinck
- Department of Bioinformatics and Computational Biology, Genentech, South San Francisco, California, United States of America
- Department of Molecular Biology, Genentech, South San Francisco, California, United States of America
| | - Zora Modrusan
- Department of Molecular Biology, Genentech, South San Francisco, California, United States of America
| | - Jeffrey H. Miner
- Division of Nephrology, Washington University School of Medicine, St. Louis, Missouri, United States of America
| | - Andrey S. Shaw
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, United States of America
- Department of Research Biology, Genentech, South San Francisco, California, United States of America
- * E-mail:
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37
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Yang X, You J, Luo W, Yue J, Ma L, Xiao W, Zhu D, Wu Z, Wang D, Nadiminty N, Gao AC, Zhou Q. The N-terminal kinase suppressor of Ras complex has a weak nucleoside diphosphate kinase activity. Thorac Cancer 2018; 1:109-115. [PMID: 27755802 DOI: 10.1111/j.1759-7714.2010.00020.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
INTRODUCTION An increasing number of studies have proven that the kinase suppressor of Ras (KSR1) functions as a scaffolding protein that coordinates the assembly of a multiprotein complex containing mitogen-activated protein kinase and its upstream regulators. However, a few studies have reported that KSR1 can activate c-Raf-1. Therefore, whether KSR1 possesses a kinase activity has been an unresolved issue until now. MATERIALS AND METHODS pCMV-Tag2b-KSR plasmids were transfected into 293T cells. In vitro autophosphorylation was assayed by autoradiography and in vitro kinase was assayed by reversed-phase high performance liquid chromatography. RESULTS We observed that wild-type KSR1 (WT-KSR) and N-terminal KSR1 (N-KSR) were phosphorylated, but the C-terminal KSR1 (C-KSR) and vector proteins were not. The high performance liquid chromatography profile showed not only the adenosine diphosphate peak but also the uridine triphosphate peak in the WT-KSR and N-KSR groups; both peaks were considerably more significant in these groups than in the others. The WT-KSR and N-KSR groups exhibited transphosphorylation and autophosphorylation activities, while the other groups revealed almost no activity. DISCUSSION Here, we demonstrate the nucleoside diphosphate kinase activity of the KSR1 complex and that this activity can be independent of the C-terminus of KSR1. Additionally, we found the autophosphorylation activity of the KSR1 complex to be extremely weak, suggesting that the KSR1 complex possesses an extremely weak kinase activity irrespective of whether it is nucleoside diphosphate kinase activity or serine/threonine protein kinase activity. These data suggest that the kinase activity of the KSR1 complex is derived from its associated proteins.
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Affiliation(s)
- Xueqin Yang
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Jiacong You
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Wei Luo
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Jiao Yue
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Li Ma
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Wen Xiao
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Daxing Zhu
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Zhihao Wu
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Dong Wang
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Nagalakshmi Nadiminty
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Allen C Gao
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
| | - Qinghua Zhou
- Tianjin Key Laboratory of Lung Cancer metastasis and Tumor Microenvironment, Tianjin Lung Cancer Institute, Tianjin Medical University General Hospital, Tianjin, China Cancer Center, Institute of Surgery Research and Daping Hospital, Third Military Medical University, Chongqing, China Department of Urology and Cancer Center, University of California Davis Medical Center, Sacramento, USA
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Wolfstetter G, Pfeifer K, van Dijk JR, Hugosson F, Lu X, Palmer RH. The scaffolding protein Cnk binds to the receptor tyrosine kinase Alk to promote visceral founder cell specification inDrosophila. Sci Signal 2017; 10:10/502/eaan0804. [DOI: 10.1126/scisignal.aan0804] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Golden A. From phenologs to silent suppressors: Identifying potential therapeutic targets for human disease. Mol Reprod Dev 2017; 84:1118-1132. [PMID: 28834577 DOI: 10.1002/mrd.22880] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 08/04/2017] [Indexed: 12/16/2022]
Abstract
Orthologous phenotypes, or phenologs, are seemingly unrelated phenotypes generated by mutations in a conserved set of genes. Phenologs have been widely observed and accepted by those who study model organisms, and allow one to study a set of genes in a model organism to learn more about the function of those genes in other organisms, including humans. At the cellular and molecular level, these conserved genes likely function in a very similar mode, but are doing so in different tissues or cell types and can result in different phenotypic effects. For example, the RAS-RAF-MEK-MAPK pathway in animals is a highly conserved signaling pathway that animals adopted for numerous biological processes, such as vulval induction in Caenorhabditis elegans and cell proliferation in mammalian cells; but this same gene set has been co-opted to function in a variety of cellular contexts. In this review, I give a few examples of how suppressor screens in model organisms (with a emphasis on C. elegans) can identify new genes that function in a conserved pathway in many other organisms. I also demonstrate how the identification of such genes can lead to important insights into mammalian biology. From such screens, an occasional silent suppressor that does not cause a phenotype on its own is found; such suppressors thus make for good candidates as therapeutic targets.
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Affiliation(s)
- Andy Golden
- Laboratory of Biochemistry and Genetics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland
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Frodyma D, Neilsen B, Costanzo-Garvey D, Fisher K, Lewis R. Coordinating ERK signaling via the molecular scaffold Kinase Suppressor of Ras. F1000Res 2017; 6:1621. [PMID: 29026529 PMCID: PMC5583734 DOI: 10.12688/f1000research.11895.1] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 09/01/2017] [Indexed: 12/17/2022] Open
Abstract
Many cancers, including those of the colon, lung, and pancreas, depend upon the signaling pathways induced by mutated and constitutively active Ras. The molecular scaffolds Kinase Suppressor of Ras 1 and 2 (KSR1 and KSR2) play potent roles in promoting Ras-mediated signaling through the Raf/MEK/ERK kinase cascade. Here we summarize the canonical role of KSR in cells, including its central role as a scaffold protein for the Raf/MEK/ERK kinase cascade, its regulation of various cellular pathways mediated through different binding partners, and the phenotypic consequences of KSR1 or KSR2 genetic inactivation. Mammalian KSR proteins have a demonstrated role in cellular and organismal energy balance with implications for cancer and obesity. Targeting KSR1 in cancer using small molecule inhibitors has potential for therapy with reduced toxicity to the patient. RNAi and small molecule screens using KSR1 as a reference standard have the potential to expose and target vulnerabilities in cancer. Interestingly, although KSR1 and KSR2 are similar in structure, KSR2 has a distinct physiological role in regulating energy balance. Although KSR proteins have been studied for two decades, additional analysis is required to elucidate both the regulation of these molecular scaffolds and their potent effect on the spatial and temporal control of ERK activation in health and disease.
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Affiliation(s)
- Danielle Frodyma
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Beth Neilsen
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Diane Costanzo-Garvey
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Kurt Fisher
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, Nebraska, USA
| | - Robert Lewis
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, Nebraska, USA.,Fred & Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska, USA
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Neilsen BK, Frodyma DE, Lewis RE, Fisher KW. KSR as a therapeutic target for Ras-dependent cancers. Expert Opin Ther Targets 2017; 21:499-509. [PMID: 28333549 DOI: 10.1080/14728222.2017.1311325] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION Targeting downstream effectors required for oncogenic Ras signaling is a potential alternative or complement to the development of more direct approaches targeting Ras in the treatment of Ras-dependent cancers. Areas covered: Here we review literature pertaining to the molecular scaffold Kinase Suppressor of Ras (KSR) and its role in promoting signals critical to tumor maintenance. We summarize the phenotypes in knockout models, describe the role of KSR in cancer, and outline the structure and function of the KSR1 and KSR2 proteins. We then focus on the most recent literature that describes the crystal structure of the kinase domain of KSR2 in complex with MEK1, KSR-RAF dimerization particularly in response to RAF inhibition, and novel attempts to target KSR proteins directly. Expert opinion: KSR is a downstream effector of Ras-mediated tumorigenesis that is dispensable for normal growth and development, making it a desirable target for the development of novel therapeutics with a high therapeutic index. Recent advances have revealed that KSR can be functionally inhibited using a small molecule that stabilizes KSR in an inactive conformation. The efficacy and potential for this novel approach to be used clinically in the treatment of Ras-driven cancers is still being investigated.
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Affiliation(s)
- Beth K Neilsen
- a Eppley Institute, Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA
| | - Danielle E Frodyma
- a Eppley Institute, Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA
| | - Robert E Lewis
- a Eppley Institute, Fred & Pamela Buffett Cancer Center , University of Nebraska Medical Center , Omaha , NE , USA.,b Department of Pathology and Microbiology , University of Nebraska Medical Center , Omaha , NE , USA
| | - Kurt W Fisher
- b Department of Pathology and Microbiology , University of Nebraska Medical Center , Omaha , NE , USA
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Gauthier K, Rocheleau CE. C. elegans Vulva Induction: An In Vivo Model to Study Epidermal Growth Factor Receptor Signaling and Trafficking. Methods Mol Biol 2017; 1652:43-61. [PMID: 28791633 DOI: 10.1007/978-1-4939-7219-7_3] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Epidermal growth factor receptor (EGFR)-mediated activation of the canonical Ras/MAPK signaling cascade is responsible for cell proliferation and cell growth. This signaling pathway is frequently overactivated in epithelial cancers; therefore, studying regulation of this pathway is crucial not only for our fundamental understanding of cell biology but also for our ability to treat EGFR-related disease. Genetic model organisms such as Caenorhabditis elegans, a hermaphroditic nematode, played a vital role in identifying components of the EGFR/Ras/MAPK pathway and delineating their order of function, and continues to play a role in identifying novel regulators of the pathway. Polarized activation of LET-23, the C. elegans homolog of EGFR, is responsible for induction of the vulval cell fate; perturbations in this signaling pathway produce either a vulvaless or multivulva phenotype. The translucent cuticle of the nematode facilitates in vivo visualization of the receptor, revealing that localization of LET-23 EGFR is tightly regulated and linked to its function. In this chapter, we review the methods used to harness vulva development as a tool for studying EGFR signaling and trafficking in C. elegans.
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Affiliation(s)
- Kimberley Gauthier
- Department of Anatomy and Cell Biology, McGill University, Montreal, Canada
- Centre for Translational Biology, Research Institute of the McGill University Health Centre, Montreal, Canada
| | - Christian E Rocheleau
- Department of Anatomy and Cell Biology, McGill University, Montreal, Canada.
- Centre for Translational Biology, Research Institute of the McGill University Health Centre, Montreal, Canada.
- Division of Endocrinology and Metabolism, Department of Medicine, McGill University, Montreal, Canada.
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Abstract
Cells respond to changes in their environment, to developmental cues, and to pathogen aggression through the action of a complex network of proteins. These networks can be decomposed into a multitude of signaling pathways that relay signals from the microenvironment to the cellular components involved in eliciting a specific response. Perturbations in these signaling processes are at the root of multiple pathologies, the most notable of these being cancer. The study of receptor tyrosine kinase (RTK) signaling led to the first description of a mechanism whereby an extracellular signal is transmitted to the nucleus to induce a transcriptional response. Genetic studies conducted in drosophila and nematodes have provided key elements to this puzzle. Here, we briefly discuss the somewhat lesser known contribution of these multicellular organisms to our understanding of what has come to be known as the prototype of signaling pathways. We also discuss the ostensibly much larger network of regulators that has emerged from recent functional genomic investigations of RTK/RAS/ERK signaling.
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Affiliation(s)
- Dariel Ashton-Beaucage
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montreal, QC, Canada, H3C 3J7
| | - Marc Therrien
- Institute for Research in Immunology and Cancer, Laboratory of Intracellular Signaling, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montreal, QC, Canada, H3C 3J7.
- Département de Pathologie et de Biologie Cellulaire, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Montreal, QC, Canada, H3C 3J7.
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Lake D, Corrêa SAL, Müller J. Negative feedback regulation of the ERK1/2 MAPK pathway. Cell Mol Life Sci 2016; 73:4397-4413. [PMID: 27342992 PMCID: PMC5075022 DOI: 10.1007/s00018-016-2297-8] [Citation(s) in RCA: 351] [Impact Index Per Article: 43.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 06/16/2016] [Accepted: 06/17/2016] [Indexed: 01/04/2023]
Abstract
The extracellular signal-regulated kinase 1/2 (ERK1/2) mitogen-activated protein kinase (MAPK) signalling pathway regulates many cellular functions, including proliferation, differentiation, and transformation. To reliably convert external stimuli into specific cellular responses and to adapt to environmental circumstances, the pathway must be integrated into the overall signalling activity of the cell. Multiple mechanisms have evolved to perform this role. In this review, we will focus on negative feedback mechanisms and examine how they shape ERK1/2 MAPK signalling. We will first discuss the extensive number of negative feedback loops targeting the different components of the ERK1/2 MAPK cascade, specifically the direct posttranslational modification of pathway components by downstream protein kinases and the induction of de novo gene synthesis of specific pathway inhibitors. We will then evaluate how negative feedback modulates the spatiotemporal signalling dynamics of the ERK1/2 pathway regarding signalling amplitude and duration as well as subcellular localisation. Aberrant ERK1/2 activation results in deregulated proliferation and malignant transformation in model systems and is commonly observed in human tumours. Inhibition of the ERK1/2 pathway thus represents an attractive target for the treatment of malignant tumours with increased ERK1/2 activity. We will, therefore, discuss the effect of ERK1/2 MAPK feedback regulation on cancer treatment and how it contributes to reduced clinical efficacy of therapeutic agents and the development of drug resistance.
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Affiliation(s)
- David Lake
- Warwick Medical School, University of Warwick, Coventry, UK
| | - Sonia A L Corrêa
- School of Life Sciences, University of Warwick, Coventry, UK
- Faculty of Life Sciences, University of Bradford, Bradford, UK
| | - Jürgen Müller
- Warwick Medical School, University of Warwick, Coventry, UK.
- Aston Medical Research Institute, Aston Medical School, Aston University, Birmingham, B4 7ET, UK.
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Dhawan NS, Scopton AP, Dar AC. Small molecule stabilization of the KSR inactive state antagonizes oncogenic Ras signalling. Nature 2016; 537:112-116. [PMID: 27556948 PMCID: PMC5161575 DOI: 10.1038/nature19327] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2015] [Accepted: 07/22/2016] [Indexed: 12/05/2022]
Abstract
Deregulation of the Ras–mitogen activated protein kinase (MAPK) pathway is an early event in many different cancers and a key driver of resistance to targeted therapies1. Sustained signalling through this pathway is caused most often by mutations in K-Ras, which biochemically favours the stabilization of active RAF signalling complexes2. Kinase suppressor of Ras (KSR) is a MAPK scaffold3–5 that is subject to allosteric regulation through dimerization with RAF6,7. Direct targeting of KSR could have important therapeutic implications for cancer; however, testing this hypothesis has been difficult owing to a lack of small-molecule antagonists of KSR function. Guided by KSR mutations that selectively suppress oncogenic, but not wild-type, Ras signalling, we developed a class of compounds that stabilize a previously unrecognized inactive state of KSR. These compounds, exemplified by APS-2-79, modulate KSR-dependent MAPK signalling by antagonizing RAF heterodimerization as well as the conformational changes required for phosphorylation and activation of KSR-bound MEK (mitogen-activated protein kinase kinase). Furthermore, APS-2-79 increased the potency of several MEK inhibitors specifically within Ras-mutant cell lines by antagonizing release of negative feedback signalling, demonstrating the potential of targeting KSR to improve the efficacy of current MAPK inhibitors. These results reveal conformational switching in KSR as a druggable regulator of oncogenic Ras, and further suggest co-targeting of enzymatic and scaffolding activities within Ras–MAPK signalling complexes as a therapeutic strategy for overcoming Ras-driven cancers.
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Affiliation(s)
- Neil S Dhawan
- Department of Oncological Sciences, The Tisch Cancer Institute, The Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA.,Department of Structural and Chemical Biology, The Tisch Cancer Institute, The Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Alex P Scopton
- Department of Oncological Sciences, The Tisch Cancer Institute, The Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA.,Department of Structural and Chemical Biology, The Tisch Cancer Institute, The Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
| | - Arvin C Dar
- Department of Oncological Sciences, The Tisch Cancer Institute, The Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA.,Department of Structural and Chemical Biology, The Tisch Cancer Institute, The Icahn School of Medicine at Mount Sinai, New York, New York 10029, USA
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Abstract
Cancer is a complex disease that affects multiple organs. Whole-body animal models provide important insights into oncology that can lead to clinical impact. Here, we review novel concepts that Drosophila studies have established for cancer biology, drug discovery, and patient therapy. Genetic studies using Drosophila have explored the roles of oncogenes and tumor-suppressor genes that when dysregulated promote cancer formation, making Drosophila a useful model to study multiple aspects of transformation. Not limited to mechanism analyses, Drosophila has recently been showing its value in facilitating drug development. Flies offer rapid, efficient platforms by which novel classes of drugs can be identified as candidate anticancer leads. Further, we discuss the use of Drosophila as a platform to develop therapies for individual patients by modeling the tumor's genetic complexity. Drosophila provides both a classical and a novel tool to identify new therapeutics, complementing other more traditional cancer tools.
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Affiliation(s)
- M Sonoshita
- Icahn School of Medicine at Mount Sinai, New York, NY, United States; Kyoto University Graduate School of Medicine, Kyoto, Japan
| | - R L Cagan
- Icahn School of Medicine at Mount Sinai, New York, NY, United States.
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47
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Flibotte S, Kim BR, Van de Laar E, Brown L, Moghal N. The SWI/SNF chromatin remodeling complex exerts both negative and positive control over LET-23/EGFR-dependent vulval induction in Caenorhabditis elegans. Dev Biol 2016; 415:46-63. [PMID: 27207389 DOI: 10.1016/j.ydbio.2016.05.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Revised: 05/05/2016] [Accepted: 05/09/2016] [Indexed: 11/19/2022]
Abstract
Signaling by the epidermal growth factor receptor (EGFR) generates diverse developmental patterns. This requires precise control over the location and intensity of signaling. Elucidation of these regulatory mechanisms is important for understanding development and disease pathogenesis. In Caenorhabditis elegans, LIN-3/EGF induces vulval formation in the mid-body, which requires LET-23/EGFR activation only in P6.p, the vulval progenitor nearest the LIN-3 source. To identify mechanisms regulating this signaling pattern, we screened for mutations that cooperate with a let-23 gain-of-function allele to cause ectopic vulval induction. Here, we describe a dominant gain-of-function mutation in swsn-4, a component of SWI/SNF chromatin remodeling complexes. Loss-of-function mutations in multiple SWI/SNF components reveal that weak reduction in SWI/SNF activity causes ectopic vulval induction, while stronger reduction prevents adoption of vulval fates, a phenomenon also observed with increasing loss of LET-23 activity. High levels of LET-23 expression in P6.p are thought to locally sequester LIN-3, thereby preventing ectopic vulval induction, with slight reductions in its expression interfering with LIN-3 sequestration, but not vulval fate signaling. We find that SWI/SNF positively regulates LET-23 expression in P6.p descendants, providing an explanation for the similarities between let-23 and SWI/SNF mutant phenotypes. However, SWI/SNF regulation of LET-23 expression is cell-specific, with SWI/SNF repressing its expression in the ALA neuron. The swsn-4 gain-of-function mutation affects the PTH domain, and provides the first evidence that its auto-inhibitory function in yeast Sth1p is conserved in metazoan chromatin remodelers. Finally, our work supports broad use of SWI/SNF in regulating EGFR signaling during development, and suggests that dominant SWI/SNF mutations in certain human congenital anomaly syndromes may be gain-of-functions.
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Affiliation(s)
- Stephane Flibotte
- Department of Zoology, University of British Columbia, Vancouver, British Columbia, Canada V6T 1Z4.
| | - Bo Ram Kim
- Princess Margaret Cancer Centre/University Health Network, Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 1L7.
| | - Emily Van de Laar
- Princess Margaret Cancer Centre/University Health Network, Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 1L7.
| | - Louise Brown
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, Canada M5G 1X5.
| | - Nadeem Moghal
- Princess Margaret Cancer Centre/University Health Network, Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada M5G 1L7.
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Liang Y, Sheikh F. Scaffold Proteins Regulating Extracellular Regulated Kinase Function in Cardiac Hypertrophy and Disease. Front Pharmacol 2016; 7:37. [PMID: 26973524 PMCID: PMC4770026 DOI: 10.3389/fphar.2016.00037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2015] [Accepted: 02/11/2016] [Indexed: 01/07/2023] Open
Abstract
The mitogen activated protein kinase (MAPK)-extracellular regulated kinase 1/2 (ERK1/2) pathway is a central downstream signaling pathway that is activated in cardiac muscle cells during mechanical and agonist-mediated hypertrophy. Studies in genetic mouse models deficient in ERK-associated MAPK components pathway have further reinforced a direct role for this pathway in stress-induced cardiac hypertrophy and disease. However, more recent studies have highlighted that these signaling pathways may exert their regulatory functions in a more compartmentalized manner in cardiac muscle. Emerging data has uncovered specific MAPK scaffolding proteins that tether MAPK/ERK signaling specifically at the sarcomere and plasma membrane in cardiac muscle and show that deficiencies in these scaffolding proteins alter ERK activity and phosphorylation, which are then critical in altering the cardiac myocyte response to stress-induced hypertrophy and disease progression. In this review, we provide insights on ERK-associated scaffolding proteins regulating cardiac myofilament function and their impact on cardiac hypertrophy and disease.
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Affiliation(s)
- Yan Liang
- Department of Medicine, University of California-San Diego, La Jolla CA, USA
| | - Farah Sheikh
- Department of Medicine, University of California-San Diego, La Jolla CA, USA
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Differential localization of A-Raf regulates MST2-mediated apoptosis during epithelial differentiation. Cell Death Differ 2016; 23:1283-95. [PMID: 26891695 DOI: 10.1038/cdd.2016.2] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2015] [Revised: 12/20/2016] [Accepted: 01/05/2016] [Indexed: 12/12/2022] Open
Abstract
A-Raf belongs to the family of oncogenic Raf kinases that are involved in mitogenic signaling by activating the MEK-ERK pathway. Low kinase activity of A-Raf toward MEK suggested that A-Raf might have alternative functions. We recently identified A-Raf as a potent inhibitor of the proapoptotic mammalian sterile 20-like kinase (MST2) tumor suppressor pathway in several cancer entities including head and neck, colon, and breast. Independent of kinase activity, A-Raf binds to MST2 thereby efficiently inhibiting apoptosis. Here, we show that the interaction of A-Raf with the MST2 pathway is regulated by subcellular compartmentalization. Although in proliferating normal cells and tumor cells A-Raf localizes to the mitochondria, differentiated non-carcinogenic cells of head and neck epithelia, which express A-Raf at the plasma membrane. The constitutive or induced re-localization of A-Raf to the plasma membrane compromises its ability to efficiently sequester and inactivate MST2, thus rendering cells susceptible to apoptosis. Physiologically, A-Raf re-localizes to the plasma membrane upon epithelial differentiation in vivo. This re-distribution is regulated by the scaffold protein kinase suppressor of Ras 2 (KSR2). Downregulation of KSR2 during mammary epithelial cell differentiation or siRNA-mediated knockdown re-localizes A-Raf to the plasma membrane causing the release of MST2. By using the MCF7 cell differentiation system, we could demonstrate that overexpression of A-Raf in MCF7 cells, which induces differentiation. Our findings offer a new paradigm to understand how differential localization of Raf complexes affects diverse signaling functions in normal cells and carcinomas.
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The scaffold protein KSR1, a novel therapeutic target for the treatment of Merlin-deficient tumors. Oncogene 2015; 35:3443-53. [PMID: 26549023 DOI: 10.1038/onc.2015.404] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2015] [Revised: 09/02/2015] [Accepted: 09/18/2015] [Indexed: 12/27/2022]
Abstract
Merlin has broad tumor-suppressor functions as its mutations have been identified in multiple benign tumors and malignant cancers. In all schwannomas, the majority of meningiomas and 1/3 of ependymomas Merlin loss is causative. In neurofibromatosis type 2, a dominantly inherited tumor disease because of the loss of Merlin, patients suffer from multiple nervous system tumors and die on average around age 40. Chemotherapy is not effective and tumor localization and multiplicity make surgery and radiosurgery challenging and morbidity is often considerable. Thus, a new therapeutic approach is needed for these tumors. Using a primary human in vitro model for Merlin-deficient tumors, we report that the Ras/Raf/mitogen-activated protein, extracellular signal-regulated kinase kinase (MEK)/extracellular signal-regulated kinase (ERK) scaffold, kinase suppressor of Ras 1 (KSR1), has a vital role in promoting schwannomas development. We show that KSR1 overexpression is involved in many pathological phenotypes caused by Merlin loss, namely multipolar morphology, enhanced cell-matrix adhesion, focal adhesion and, most importantly, increased proliferation and survival. Our data demonstrate that KSR1 has a wider role than MEK1/2 in the development of schwannomas because adhesion is more dependent on KSR1 than MEK1/2. Immunoprecipitation analysis reveals that KSR1 is a novel binding partner of Merlin, which suppresses KSR1's function by inhibiting the binding between KSR1 and c-Raf. Our proteomic analysis also demonstrates that KSR1 interacts with several Merlin downstream effectors, including E3 ubiquitin ligase CRL4(DCAF1). Further functional studies suggests that KSR1 and DCAF1 may co-operate to regulate schwannomas formation. Taken together, these findings suggest that KSR1 serves as a potential therapeutic target for Merlin-deficient tumors.
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