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Casacuberta-Serra S, González-Larreategui Í, Capitán-Leo D, Soucek L. MYC and KRAS cooperation: from historical challenges to therapeutic opportunities in cancer. Signal Transduct Target Ther 2024; 9:205. [PMID: 39164274 PMCID: PMC11336233 DOI: 10.1038/s41392-024-01907-z] [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: 01/12/2024] [Revised: 06/05/2024] [Accepted: 06/24/2024] [Indexed: 08/22/2024] Open
Abstract
RAS and MYC rank amongst the most commonly altered oncogenes in cancer, with RAS being the most frequently mutated and MYC the most amplified. The cooperative interplay between RAS and MYC constitutes a complex and multifaceted phenomenon, profoundly influencing tumor development. Together and individually, these two oncogenes regulate most, if not all, hallmarks of cancer, including cell death escape, replicative immortality, tumor-associated angiogenesis, cell invasion and metastasis, metabolic adaptation, and immune evasion. Due to their frequent alteration and role in tumorigenesis, MYC and RAS emerge as highly appealing targets in cancer therapy. However, due to their complex nature, both oncogenes have been long considered "undruggable" and, until recently, no drugs directly targeting them had reached the clinic. This review aims to shed light on their complex partnership, with special attention to their active collaboration in fostering an immunosuppressive milieu and driving immunotherapeutic resistance in cancer. Within this review, we also present an update on the different inhibitors targeting RAS and MYC currently undergoing clinical trials, along with their clinical outcomes and the different combination strategies being explored to overcome drug resistance. This recent clinical development suggests a paradigm shift in the long-standing belief of RAS and MYC "undruggability", hinting at a new era in their therapeutic targeting.
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Affiliation(s)
| | - Íñigo González-Larreategui
- Models of cancer therapies Laboratory, Vall d'Hebron Institute of Oncology, Cellex Centre, Hospital University Vall d'Hebron Campus, Barcelona, Spain
| | - Daniel Capitán-Leo
- Models of cancer therapies Laboratory, Vall d'Hebron Institute of Oncology, Cellex Centre, Hospital University Vall d'Hebron Campus, Barcelona, Spain
| | - Laura Soucek
- Peptomyc S.L., Barcelona, Spain.
- Models of cancer therapies Laboratory, Vall d'Hebron Institute of Oncology, Cellex Centre, Hospital University Vall d'Hebron Campus, Barcelona, Spain.
- Institució Catalana de Recerca i Estudis Avançats, Barcelona, Spain.
- Department of Biochemistry and Molecular Biology, Universitat Autonoma de Barcelona, Bellaterra, Spain.
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2
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Spencer-Smith R, Morrison DK. Regulation of RAF family kinases: new insights from recent structural and biochemical studies. Biochem Soc Trans 2024; 52:1061-1069. [PMID: 38695730 PMCID: PMC11346419 DOI: 10.1042/bst20230552] [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: 02/24/2024] [Revised: 04/18/2024] [Accepted: 04/22/2024] [Indexed: 06/27/2024]
Abstract
The RAF kinases are required for signal transduction through the RAS-RAF-MEK-ERK pathway, and their activity is frequently up-regulated in human cancer and the RASopathy developmental syndromes. Due to their complex activation process, developing drugs that effectively target RAF function has been a challenging endeavor, highlighting the need for a more detailed understanding of RAF regulation. This review will focus on recent structural and biochemical studies that have provided 'snapshots' into the RAF regulatory cycle, revealing structures of the autoinhibited BRAF monomer, active BRAF and CRAF homodimers, as well as HSP90/CDC37 chaperone complexes containing CRAF or BRAFV600E. In addition, we will describe the insights obtained regarding how BRAF transitions between its regulatory states and examine the roles that various BRAF domains and 14-3-3 dimers play in both maintaining BRAF as an autoinhibited monomer and in facilitating its transition to an active dimer. We will also address the function of the HSP90/CDC37 chaperone complex in stabilizing the protein levels of CRAF and certain oncogenic BRAF mutants, and in serving as a platform for RAF dephosphorylation mediated by the PP5 protein phosphatase. Finally, we will discuss the regulatory differences observed between BRAF and CRAF and how these differences impact the function of BRAF and CRAF as drivers of human disease.
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Affiliation(s)
- Russell Spencer-Smith
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702, U.S.A
| | - Deborah K. Morrison
- Laboratory of Cell and Developmental Signaling, Center for Cancer Research, National Cancer Institute-Frederick, Frederick, MD 21702, U.S.A
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3
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Spencer-Smith R. The RAF cysteine-rich domain: Structure, function, and role in disease. Adv Cancer Res 2024; 164:69-91. [PMID: 39306370 DOI: 10.1016/bs.acr.2024.04.009] [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: 09/25/2024]
Abstract
RAF kinases, consisting of ARAF, BRAF and CRAF, are direct effectors of RAS GTPases and critical for signal transduction through the RAS-MAPK pathway. Driver mutations in BRAF are commonplace in human cancer, while germline mutations in BRAF and CRAF cause RASopathy development syndromes. However, there remains a lack of effective drugs that target RAF function, which is partially due to the complexity of the RAF activation cycle. Therefore, greater understanding of RAF regulation is required to identify new approaches that target its function in disease. A key piece of this puzzle is the RAF zinc finger, often referred to as the cysteine-rich domain (CRD). The CRD is a lipid and protein binding domain which plays complex and opposing roles in the RAF activation cycle. Firstly, it supports the RAS-RAF interaction during RAF activation by binding to phosphatidylserine (PS) in the plasma membrane and by making direct RAS contacts. Conversely, under quiescent conditions the CRD also plays a critical role in maintaining RAF in a closed, autoinhibited state. However, the interplay between these activities and their relative importance for RAF activation were not well understood. Recent structural and biochemical studies have contributed greatly to our understanding of these roles and identified functional differences between BRAF CRD and that of CRAF. This chapter provides an in-depth review of the CRDs roles in RAF regulation and how they may inform novel approaches to target RAF function.
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Affiliation(s)
- Russell Spencer-Smith
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina.
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4
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Hiroshima M, Bannai H, Matsumoto G, Ueda M. Application of single-molecule analysis to singularity phenomenon of cells. Biophys Physicobiol 2024; 21:e211018. [PMID: 39175861 PMCID: PMC11338674 DOI: 10.2142/biophysico.bppb-v21.s018] [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: 02/29/2024] [Accepted: 05/02/2024] [Indexed: 08/24/2024] Open
Abstract
Single-molecule imaging in living cells is an effective tool for elucidating the mechanisms of cellular phenomena at the molecular level. However, the analysis was not designed for throughput and requires high expertise, preventing it from reaching large scale, which is necessary when searching for rare cells that induce singularity phenomena. To overcome this limitation, we have automated the imaging procedures by combining our own focusing device, artificial intelligence, and robotics. The apparatus, called automated in-cell single-molecule imaging system (AiSIS), achieves a throughput that is a hundred-fold higher than conventional manual imaging operations, enabling the analysis of molecular events by individual cells across a large population. Here, using AiSIS, we demonstrate the single-molecule imaging of molecular behaviors and reactions related to tau protein aggregation, which is considered a singularity phenomenon in neurological disorders. Changes in the dynamics and kinetics of molecular events were observed inside and on the basal membrane of cells after the induction of aggregation. Additionally, to detect rare cells based on the molecular behavior, we developed a method to identify the state of individual cells defined by the quantitative distribution of molecular mobility and clustering. Using this method, cellular variations in receptor behavior were shown to decrease following ligand stimulation. This cell state analysis based on large-scale single-molecule imaging by AiSIS will advance the study of molecular mechanisms causing singularity phenomena.
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Affiliation(s)
- Michio Hiroshima
- Laboratory of Single Molecule Biology, Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan
- Laboratory for Cell Signaling Dynamics, RIKEN BDR, Osaka 565-0874, Japan
| | - Hiroko Bannai
- School of Advanced Science and Engineering, Department of Electrical Engineering and Biosciences, Waseda University, Shinjuku-ku, Tokyo 162-0056, Japan
| | - Gen Matsumoto
- Department of Neurological Disease Control, Osaka Metropolitan University Graduate School of Medicine, Osaka 545-8585, Japan
- Department of Anatomy and Neurobiology, Nagasaki University School of Medicine, Nagasaki 852-8523, Japan
| | - Masahiro Ueda
- Laboratory of Single Molecule Biology, Graduate School of Frontier Biosciences, Osaka University, Osaka 565-0871, Japan
- Laboratory for Cell Signaling Dynamics, RIKEN BDR, Osaka 565-0874, Japan
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5
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Bhatia V, Esmati L, Bhullar RP. Regulation of Ras p21 and RalA GTPases activity by quinine in mammary epithelial cells. Mol Cell Biochem 2024; 479:567-577. [PMID: 37131040 DOI: 10.1007/s11010-023-04725-z] [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: 12/21/2022] [Accepted: 03/31/2023] [Indexed: 05/04/2023]
Abstract
Quinine, a bitter compound, can act as an agonist to activate the family of bitter taste G protein-coupled receptor family of proteins. Previous work from our laboratory has demonstrated that quinine causes activation of RalA, a Ras p21-related small G protein. Ral proteins can be activated directly or indirectly through an alternative pathway that requires Ras p21 activation resulting in the recruitment of RalGDS, a guanine nucleotide exchange factor for Ral. Using normal mammary epithelial (MCF-10A) and non-invasive mammary epithelial (MCF-7) cell lines, we investigated the effect of quinine in regulating Ras p21 and RalA activity. Results showed that in the presence of quinine, Ras p21 is activated in both MCF-10A and MCF-7 cells; however, RalA was inhibited in MCF-10A cells, and no effect was observed in the case of MCF-7 cells. MAP kinase, a downstream effector for Ras p21, was activated in both MCF-10A and MCF-7 cells. Western blot analysis confirmed the expression of RalGDS in MCF-10A cells and MCF-7 cells. The expression of RalGDS was higher in MCF-10A cells in comparison to the MCF-7 cells. Although RalGDS was detected in MCF-10A and MCF-7 cells, it did not result in RalA activation upon Ras p21 activation with quinine suggesting that the Ras p21-RalGDS-RalA pathway is not active in the MCF-10A cells. The inhibition of RalA activity in MCF-10A cells due to quinine could be as a result of a direct effect of this bitter compound on RalA. Protein modeling and ligand docking analysis demonstrated that quinine can interact with RalA through the R79 amino acid, which is located in the switch II region loop of the RalA protein. It is possible that quinine causes a conformational change that results in the inhibition of RalA activation even though RalGDS is present in the cell. More studies are needed to elucidate the mechanism(s) that regulate Ral activity in mammary epithelial cells.
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Affiliation(s)
- Vikram Bhatia
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R3E 0W2, Canada
- Children's Hospital Research Institute of Manitoba (CHRIM), Winnipeg, MB, R3E 3P4, Canada
| | - Laya Esmati
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R3E 0W2, Canada
| | - Rajinder P Bhullar
- Manitoba Chemosensory Biology Research Group and Department of Oral Biology, Dr. Gerald Niznick College of Dentistry, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, R3E 0W2, Canada.
- Department of Biochemistry and Medical Genetics, University of Manitoba, Winnipeg, MB, R3E 0W2, Canada.
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6
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Hu M, Li H, Zhu K, Guo L, Zhao M, Zhan H, Devreotes PN, Qing Q. Electric field modulation of ERK dynamics shows dependency on waveform and timing. Sci Rep 2024; 14:3167. [PMID: 38326365 PMCID: PMC10850077 DOI: 10.1038/s41598-024-53018-y] [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: 09/24/2023] [Accepted: 01/25/2024] [Indexed: 02/09/2024] Open
Abstract
Different exogenous electric fields (EF) can guide cell migration, disrupt proliferation, and program cell development. Studies have shown that many of these processes were initiated at the cell membrane, but the mechanism has been unclear, especially for conventionally non-excitable cells. In this study, we focus on the electrostatic aspects of EF coupling with the cell membrane by eliminating Faradaic processes using dielectric-coated microelectrodes. Our data unveil a distinctive biphasic response of the ERK signaling pathway of epithelial cells (MCF10A) to alternate current (AC) EF. The ERK signal exhibits both inhibition and activation phases, with the former triggered by a lower threshold of AC EF, featuring a swifter peaking time and briefer refractory periods than the later-occurring activation phase, induced at a higher threshold. Interestingly, the biphasic ERK responses are sensitive to the waveform and timing of EF stimulation pulses, depicting the characteristics of electrostatic and dissipative interactions. Blocker tests and correlated changes of active Ras on the cell membrane with ERK signals indicated that both EGFR and Ras were involved in the rich ERK dynamics induced by EF. We propose that the frequency-dependent dielectric relaxation process could be an important mechanism to couple EF energy to the cell membrane region and modulate membrane protein-initiated signaling pathways, which can be further explored to precisely control cell behavior and fate with high temporal and spatial resolution.
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Affiliation(s)
- Minxi Hu
- School of Molecular Sciences, Arizona State University, Tempe, AZ, 85287, USA
| | - Houpu Li
- Department of Physics, Arizona State University, Tempe, AZ, 85287, USA
| | - Kan Zhu
- Department of Dermatology, University of California, Davis, CA, 95616, USA
| | - Liang Guo
- College of Intelligent Systems Science and Engineering, Harbin Engineering University, Harbin, Heilongjiang, China
| | - Min Zhao
- Department of Dermatology, University of California, Davis, CA, 95616, USA
- Department of Ophthalmology and Vision Science, University of California, Davis, CA, 95616, USA
| | - Huiwang Zhan
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Peter N Devreotes
- Department of Cell Biology and Center for Cell Dynamics, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
- Department of Biological Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD, USA
| | - Quan Qing
- Department of Physics, Arizona State University, Tempe, AZ, 85287, USA.
- Biodesign Institute, Arizona State University, Tempe, AZ, 85287, USA.
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7
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Ahmad M, Movileanu L. Multiplexed imaging for probing RAS-RAF interactions in living cells. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184173. [PMID: 37211322 PMCID: PMC10330472 DOI: 10.1016/j.bbamem.2023.184173] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 04/18/2023] [Accepted: 05/08/2023] [Indexed: 05/23/2023]
Abstract
GTP-bound RAS interacts with its protein effectors in response to extracellular stimuli, leading to chemical inputs for downstream pathways. Significant progress has been made in measuring these reversible protein-protein interactions (PPIs) in various cell-free environments. Yet, acquiring high sensitivity in heterogeneous solutions remains challenging. Here, using an intermolecular fluorescence resonance energy transfer (FRET) biosensing approach, we develop a method to visualize and localize HRAS-CRAF interactions in living cells. We demonstrate that the EGFR activation and the HRAS-CRAF complex formation can be concurrently probed in a single cell. This biosensing strategy discriminates EGF-stimulated HRAS-CRAF interactions at the cell and organelle membranes. In addition, we provide quantitative FRET measurements for assessing these transient PPIs in a cell-free environment. Finally, we prove the utility of this approach by showing that an EGFR-binding compound is a potent inhibitor of HRAS-CRAF interactions. The outcomes of this work form a fundamental basis for further explorations of the spatiotemporal dynamics of various signaling networks.
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Affiliation(s)
- Mohammad Ahmad
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA
| | - Liviu Movileanu
- Department of Physics, Syracuse University, 201 Physics Building, Syracuse, New York 13244-1130, USA; Department of Biomedical and Chemical Engineering, Syracuse University, 329 Link Hall, Syracuse, NY 13244, USA; The BioInspired Institute, Syracuse University, Syracuse, NY 13244, USA.
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8
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Okamoto K, Sako Y. Two Closed Conformations of CRAF Require the 14-3-3 Binding Motifs and Cysteine-Rich Domain to be Intact in Live Cells. J Mol Biol 2023; 435:167989. [PMID: 36736888 DOI: 10.1016/j.jmb.2023.167989] [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: 10/26/2022] [Revised: 01/20/2023] [Accepted: 01/26/2023] [Indexed: 02/04/2023]
Abstract
The protein rapidly accelerated fibrosarcoma (RAF) is a kinase downstream of the membrane protein RAS in the cellular signal transduction system. In the structure of RAF, the N- and C-terminus domains are connected with a flexible linker. The open/close dynamics and dimerization of RAF are thought to regulate its activity, although the details of these conformations are unknown, especially in live cells. In this work, we used alternating laser excitation to measure cytosolic CRAF in live HeLa cells and obtained single-molecule Förster resonance energy transfer (smFRET) distributions of the structural states. We compared the results for wild-type (WT)-CRAF before and after epidermal growth factor (EGF) stimulation, with mutations of the 14-3-3 binding sites and cysteine-rich domain, and an N-terminus truncation. The smFRET distributions of full-length CRAFs were analyzed by global fitting with three beta distributions. Our results suggested that a 14-3-3 dimer bound to two sites on a single CRAF molecule and induced the formation of the autoinhibitory closed conformation. There were two closed conformations, which the majority of WT-CRAF adopted. These two conformations showed different responsiveness to EGF stimulation.
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Affiliation(s)
- Kenji Okamoto
- Cellular Informatics Laboratory, Cluster for Pioneering Research, RIKEN, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan.
| | - Yasushi Sako
- Cellular Informatics Laboratory, Cluster for Pioneering Research, RIKEN, 2-1, Hirosawa, Wako, Saitama 351-0198, Japan.
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9
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Abstract
KRAS is one of the most commonly mutated oncogene and a negative predictive factor for a number of targeted therapies. Therefore, the development of targeting strategies against mutant KRAS is urgently needed. One potential strategy involves disruption of K-Ras membrane localization, which is necessary for its proper function. In this review, we summarize the current data about the importance of membrane-anchorage of K-Ras and provide a critical evaluation of this targeting paradigm focusing mainly on prenylation inhibition. Additionally, we performed a RAS mutation-specific analysis of prenylation-related drug sensitivity data from a publicly available database (https://depmap.org/repurposing/) of three classes of prenylation inhibitors: statins, N-bisphosphonates, and farnesyl-transferase inhibitors. We observed significant differences in sensitivity to N-bisphosphonates and farnesyl-transferase inhibitors depending on KRAS mutational status and tissue of origin. These observations emphasize the importance of factors affecting efficacy of prenylation inhibition, like distinct features of different KRAS mutations, tissue-specific mutational patterns, K-Ras turnover, and changes in regulation of prenylation process. Finally, we enlist the factors that might be responsible for the large discrepancy between the outcomes in preclinical and clinical studies including methodological pitfalls, the incomplete understanding of K-Ras protein turnover, and the variation of KRAS dependency in KRAS mutant tumors.
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10
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Yoshizawa R, Umeki N, Yamamoto A, Okada M, Murata M, Sako Y. p52Shc regulates the sustainability of ERK activation in a RAF-independent manner. Mol Biol Cell 2021; 32:1838-1848. [PMID: 34260260 PMCID: PMC8684710 DOI: 10.1091/mbc.e21-01-0007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
p52SHC (SHC) and GRB2 are adaptor proteins involved in the RAS/MAPK (ERK) pathway mediating signals from cell-surface receptors to various cytoplasmic proteins. To further examine their roles in signal transduction, we studied the translocation of fluorescently labeled SHC and GRB2 to the cell surface, caused by the activation of ERBB receptors by heregulin (HRG). We simultaneously evaluated activated ERK translocation to the nucleus. Unexpectedly, the translocation dynamics of SHC were sustained when those of GRB2 were transient. The sustained localization of SHC positively correlated with the sustained nuclear localization of ERK, which became more transient after SHC knockdown. SHC-mediated PI3K activation was required to maintain the sustainability of the ERK translocation regulating MEK but not RAF. In cells overexpressing ERBB1, SHC translocation became transient, and the HRG-induced cell fate shifted from a differentiation to a proliferation bias. Our results indicate that SHC and GRB2 functions are not redundant but that SHC plays the critical role in the temporal regulation of ERK activation.
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Affiliation(s)
- Ryo Yoshizawa
- Cellular Informatics Lab, RIKEN, Wako, Saitama 351-0198, Japan.,Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan
| | - Nobuhisa Umeki
- Cellular Informatics Lab, RIKEN, Wako, Saitama 351-0198, Japan
| | | | - Mariko Okada
- Institute for Protein Research, Osaka University, Suita, Osaka 565-0871, Japan.,Center for Drug Design and Research, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki 567-0085, Japan
| | - Masayuki Murata
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro, Tokyo 153-8902, Japan
| | - Yasushi Sako
- Cellular Informatics Lab, RIKEN, Wako, Saitama 351-0198, Japan
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11
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In-Cell Single-Molecule Analysis of Molecular State and Reaction Kinetics Coupling. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2021. [PMID: 33834432 DOI: 10.1007/978-981-33-6064-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register]
Abstract
Cellular signaling is regulated by the spatiotemporal dynamics and kinetics of molecular behavior. To investigate the mechanisms at the molecular level, fluorescence single-molecule analysis is an effective method owing to the direct observation of individual molecules in situ in cells and the results in quantitative information about the behavior. The integration of machine learning into this analysis modality enables the acquisition of behavioral features at all time points of all molecules. As a case study, we described a hidden Markov model-based approach to infer the molecular states of mobility and clustering for epidermal growth factor receptor (EGFR) along a single-molecule trajectory. We reveal a scheme of the receptor signaling through the dynamic coupling of the mobility and clustering states under the influence of a local membrane structure. As the activation process progressed, EGFR generally converged to an immobile cluster. This state exhibited high affinity with a specific cytoplasmic protein, shown by two-color single-molecule analysis, and could be a platform for downstream signaling. The method was effective for elucidating the biophysical mechanisms of signaling regulation when comprehensive analysis is possible for a huge number and multiple molecular species in the signaling pathway. Thus, a fully automated system for single-molecule analysis, in which indispensable expertise was replicated using artificial intelligence, has been developed to enable in-cell large-scale analysis. This system opens new single-molecule approaches for pharmacological applications as well as the basic sciences.
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12
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Yoshizawa R, Umeki N, Yamamoto A, Murata M, Sako Y. Biphasic spatiotemporal regulation of GRB2 dynamics by p52SHC for transient RAS activation. Biophys Physicobiol 2021; 18:1-12. [PMID: 33665062 PMCID: PMC7902154 DOI: 10.2142/biophysico.bppb-v18.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Accepted: 01/05/2021] [Indexed: 12/14/2022] Open
Abstract
RTK-RAS-MAPK systems are major signaling pathways for cell fate decisions. Among the several RTK species, it is known that the transient activation of ERK (MAPK) stimulates cell proliferation, whereas its sustained activation induces cell differentiation. In both instances however, RAS activation is transient, suggesting that the strict temporal regulation of its activity is critical in normal cells. RAS on the cytoplasmic side of the plasma membrane is activated by SOS through the recruitment of GRB2/SOS complex to the RTKs that are phosphorylated after stimulation with growth factors. The adaptor protein GRB2 recognizes phospho-RTKs both directly and indirectly via another adaptor protein, SHC. We here studied the regulation of GRB2 recruitment under the SHC pathway using single-molecule imaging and fluorescence correlation spectroscopy in living cells. We stimulated MCF7 cells with a differentiation factor, heregulin, and observed the translocation, complex formation, and phosphorylation of cell signaling molecules including GRB2 and SHC. Our results suggest a biphasic regulation of the GRB2/SOS-RAS pathway by SHC: At the early stage (<10 min) of stimulation, SHC increased the amplitude of RAS activity by increasing the association sites for the GRB2/SOS complex on the plasma membrane. At the later stage however, SHC suppressed RAS activation and sequestered GRB2 molecules from the membrane through the complex formation in the cytoplasm. The latter mechanism functions additively to other mechanisms of negative feedback regulation of RAS from MEK and/or ERK to complete the transient activation dynamics of RAS.
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Affiliation(s)
- Ryo Yoshizawa
- Cellular Informatics Lab, RIKEN, Wako, Saitama 351-0198, Japan.,Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Nobuhisa Umeki
- Cellular Informatics Lab, RIKEN, Wako, Saitama 351-0198, Japan
| | | | - Masayuki Murata
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Yasushi Sako
- Cellular Informatics Lab, RIKEN, Wako, Saitama 351-0198, Japan
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13
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Yanagawa M, Sako Y. Workflows of the Single-Molecule Imaging Analysis in Living Cells: Tutorial Guidance to the Measurement of the Drug Effects on a GPCR. Methods Mol Biol 2021; 2274:391-441. [PMID: 34050488 DOI: 10.1007/978-1-0716-1258-3_32] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Single-molecule imaging (SMI) is a powerful method to measure the dynamics of membrane proteins on the cell membrane. The single-molecule tracking (SMT) analysis provides information about the diffusion dynamics, the oligomer size distribution, and the particle density change. The affinity and on/off-rate of a protein-protein interaction can be estimated from the dual-color SMI analysis. However, it is difficult for trainees to determine quantitative information from the SMI movies. The present protocol guides the detailed workflows to measure the drug-activated dynamics of a G protein-coupled receptor (GPCR) and metabotropic glutamate receptor 3 (mGluR3), by using the total internal reflection fluorescence microscopy (TIRFM). This tutorial guidance comprises an open-source software, named smDynamicsAnalyzer, with which one can easily analyze the SMT dataset by just following the workflows after building a designated folder structure ( https://github.com/masataka-yanagawa/IgorPro8-smDynamicsAnalyzer ).
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Affiliation(s)
- Masataka Yanagawa
- Cellular Informatics Laboratory, RIKEN Cluster for Pioneering Research, Saitama, Japan.
| | - Yasushi Sako
- Cellular Informatics Laboratory, RIKEN Cluster for Pioneering Research, Saitama, Japan
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14
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Wang S, Zhou D, Xu Z, Song J, Qian X, Lv X, Luan J. Anti-tumor Drug Targets Analysis: Current Insight and Future Prospect. Curr Drug Targets 2020; 20:1180-1202. [PMID: 30947670 DOI: 10.2174/1389450120666190402145325] [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: 02/05/2019] [Revised: 03/21/2019] [Accepted: 03/22/2019] [Indexed: 12/13/2022]
Abstract
The incidence and mortality of malignant tumors are on the rise, which has become the second leading cause of death in the world. At present, anti-tumor drugs are one of the most common methods for treating cancer. In recent years, with the in-depth study of tumor biology and related disciplines, it has been gradually discovered that the essence of cell carcinogenesis is the infinite proliferation of cells caused by the disorder of cell signal transduction pathways, followed by a major shift in the concept of anti-tumor drugs research and development. The focus of research and development is shifting from traditional cytotoxic drugs to a new generation of anti-tumor drugs targeted at abnormal signaling system targets in tumor cells. In this review, we summarize the targets of anti-tumor drugs and analyse the molecular mechanisms of their effects, which lay a foundation for subsequent treatment, research and development.
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Affiliation(s)
- Sheng Wang
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Dexi Zhou
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Zhenyu Xu
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Jing Song
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Xueyi Qian
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
| | - Xiongwen Lv
- The Key Laboratory of Anti-inflammatory and Immune Medicines, Ministry of Education, School of Pharmacy, Institute for Liver Disease of Anhui Medical University, Hefei, Anhui Province, China
| | - Jiajie Luan
- Department of Pharmacy, Yijishan Affiliated Hospital of Wannan Medical College, Wuhu, Anhui Province, China
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15
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Abstract
RAS was identified as a human oncogene in the early 1980s and subsequently found to be mutated in nearly 30% of all human cancers. More importantly, RAS plays a central role in driving tumor development and maintenance. Despite decades of effort, there remain no FDA approved drugs that directly inhibit RAS. The prevalence of RAS mutations in cancer and the lack of effective anti-RAS therapies stem from RAS' core role in growth factor signaling, unique structural features, and biochemistry. However, recent advances have brought promising new drugs to clinical trials and shone a ray of hope in the field. Here, we will exposit the details of RAS biology that illustrate its key role in cell signaling and shed light on the difficulties in therapeutically targeting RAS. Furthermore, past and current efforts to develop RAS inhibitors will be discussed in depth.
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Affiliation(s)
- J Matthew Rhett
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States
| | - Imran Khan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States
| | - John P O'Bryan
- Department of Cell and Molecular Pharmacology and Experimental Therapeutics, Hollings Cancer Center, Medical University of South Carolina, Charleston, SC, United States; Ralph H. Johnson VA Medical Center, Charleston, SC, United States.
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16
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Li L, Möbitz S, Winter R. Characterization of the Spatial Organization of Raf Isoforms Interacting with K-Ras4B in the Lipid Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:5944-5953. [PMID: 32390436 DOI: 10.1021/acs.langmuir.0c00770] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Activation of Raf kinases by the membrane-anchored protein K-Ras4B is a key step of cellular signal regulation. As a predominant variant of the Ras family, K-Ras4B has been considered to be a major drug target in cancer therapy. Therefore, an integrated study of Raf interaction with membrane-associated K-Ras4B is essential. While the Ras-binding domain (RBD) of Raf contains the main binding interface to K-Ras4B, its cysteine-rich domain (CRD) is thought to be responsible for its association with the membrane interface. We applied time-lapse tapping-mode atomic force microscopy to visualize and characterize the interaction of these binding motifs of A-, B-, and C-Raf isoforms with K-Ras4B in a raft-like anionic model biomembrane. However, we found that the RBDs of the Raf isomers are readily recruited to K-Ras4B nanoclusters in the lipid membrane, with different efficiencies. Unexpectedly and different from A-Raf-RBD, B- and C-Raf-RBD are able to bind markedly also directly to the lipid membrane. We also found that Raf-RBD-CRD is readily recruited to the K-Ras4B forming nanoclusters in the fluid membrane phase, with the CRD domains binding to the lipid interface. The K-Ras4B-nanoclusters are likely to enhance Raf binding and activate signaling by enriching the Raf proteins and facilitating formation of Raf dimers. Interestingly, A-, B-, and C-Raf-RBD-CRD are also able to bind directly to the heterogeneous membrane surrounding the K-Ras4B nanoclusters, which could potentially enhance the overall affinity to K-Ras4B in a Raf-isoform-dependent manner. Overall, these results provide new insights into the spatial organization of the membrane-associated Raf-Ras signaling module for the various Raf isoforms, which is important for understanding the activation of Raf kinases and required for the development of drugs against cancers through targeting Raf-Ras interactions.
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Affiliation(s)
- Lei Li
- Faculty of Chemistry and Chemical Biology, Physical Chemistry I-Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany
| | - Simone Möbitz
- Faculty of Chemistry and Chemical Biology, Physical Chemistry I-Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany
| | - Roland Winter
- Faculty of Chemistry and Chemical Biology, Physical Chemistry I-Biophysical Chemistry, TU Dortmund University, Otto-Hahn-Str. 4a, D-44227 Dortmund, Germany
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17
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Hiroshima M, Yasui M, Ueda M. Large-scale single-molecule imaging aided by artificial intelligence. Microscopy (Oxf) 2020; 69:69-78. [DOI: 10.1093/jmicro/dfz116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2019] [Revised: 11/24/2019] [Accepted: 12/16/2019] [Indexed: 01/21/2023] Open
Abstract
Abstract
Single-molecule imaging analysis has been applied to study the dynamics and kinetics of molecular behaviors and interactions in living cells. In spite of its high potential as a technique to investigate the molecular mechanisms of cellular phenomena, single-molecule imaging analysis has not been extended to a large scale of molecules in cells due to the low measurement throughput as well as required expertise. To overcome these problems, we have automated the imaging processes by using computer operations, robotics and artificial intelligence (AI). AI is an ideal substitute for expertise to obtain high-quality images for quantitative analysis. Our automated in-cell single-molecule imaging system, AiSIS, could analyze 1600 cells in 1 day, which corresponds to ∼ 100-fold higher efficiency than manual analysis. The large-scale analysis revealed cell-to-cell heterogeneity in the molecular behavior, which had not been recognized in previous studies. An analysis of the receptor behavior and downstream signaling was accomplished within a significantly reduced time frame and revealed the detailed activation scheme of signal transduction, advancing cell biology research. Furthermore, by combining the high-throughput analysis with our previous finding that a receptor changes its behavioral dynamics depending on the presence of a ligand/agonist or inhibitor/antagonist, we show that AiSIS is applicable to comprehensive pharmacological analysis such as drug screening. This AI-aided automation has wide applications for single-molecule analysis.
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Affiliation(s)
- Michio Hiroshima
- Laboratory for Cell Signaling Dynamics, RIKEN BDR, Suita 565-0874, Japan
| | | | - Masahiro Ueda
- Laboratory for Cell Signaling Dynamics, RIKEN BDR, Suita 565-0874, Japan
- Laboratory of Single Molecule Biology, Graduate School of Frontier Biosciences, Osaka University, Suita 565-0871, Japan
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18
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In-cell single-molecule FRET measurements reveal three conformational state changes in RAF protein. Biochim Biophys Acta Gen Subj 2019; 1864:129358. [PMID: 31071411 DOI: 10.1016/j.bbagen.2019.04.022] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2018] [Revised: 04/26/2019] [Accepted: 04/30/2019] [Indexed: 12/19/2022]
Abstract
BACKGROUND The structures of proteins are intimately related to their functions. Significant efforts have been dedicated to the structural investigation of proteins, mainly those of purified proteins in in vitro environments. Proteins function in living cells and thus protein structures must be regulated by interactions with various molecules, some of which participate in reaction networks, depending on the states, conditions, or actions of the cell. Therefore, it is very important to understand the structural behavior of proteins in living cells. METHODS Single-molecule Förster resonance energy transfer (smFRET) measurements were conducted using the alternative laser excitation (ALEX) technique. smFRET distributions of cytosolic Rapidly Accelerated Fibrosarcoma (RAF) proteins in living HeLa cells were obtained with exclusion of the negative effects of photobleached fluorophores and incompletely labeled proteins on smFRET. RESULTS smFRET histograms of wildtype (wt) RAF in live cells exhibited two major peaks, whereas that of the S621A mutant, which has been thought to have an expanded structure, was almost single-peaked. A population shift involving the peaks for wt RAF was detected upon epidermal growth factor stimulation. Spontaneous transitions between the conformational states corresponding to the two peaks were also detected using the FRET-two-channel kernel-based density distribution estimator method in comparison to static double-stranded DNA samples. CONCLUSIONS Cytosolic CRAF has at least three conformational states; in addition to the closed and open forms, the fully-open form was distinctly specified. Based on the results, we propose a speculative structural model for CRAF. GENERAL SIGNIFICANCE Structural distribution and changes to proteins in live cells as a result of intracellular interactions were successfully identified. smFRET using ALEX is applicable to any other cytosolic proteins.
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Surve SV, Myers PJ, Clayton SA, Watkins SC, Lazzara MJ, Sorkin A. Localization dynamics of endogenous fluorescently labeled RAF1 in EGF-stimulated cells. Mol Biol Cell 2019; 30:506-523. [PMID: 30586319 PMCID: PMC6594441 DOI: 10.1091/mbc.e18-08-0512] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Activation of the epidermal growth factor (EGF) receptor (EGFR) at the cell surface initiates signaling through the RAS-RAF-MAPK/ERK1/2 pathway and receptor endocytosis. Whether this signaling continues from endosomes remains unclear, because RAS is predominantly located on the plasma membrane, and the localization of endogenous RAF kinases, downstream effectors of RAS, is not defined. To examine RAF localization, we labeled endogenous RAF1 with mVenus using gene editing. From 10 to 15% of RAF1-mVenus (<2000 molecules/cell), which was initially entirely cytosolic, transiently translocated to the plasma membrane after EGF stimulation. Following an early burst of translocation, the membrane-associated RAF1-mVenus was undetectable by microscopy or subcellular fractionation, and this pool was estimated to be <200 molecules per cell. In contrast, persistent EGF-dependent translocation of RAF1-mVenus to the plasma membrane was driven by the RAF inhibitor sorafenib, which increases the affinity of Ras-GTP:RAF1 interactions. RAF1-mVenus was not found in EGFR-containing endosomes under any conditions. Computational modeling of RAF1 dynamics revealed that RAF1 membrane abundance is controlled most prominently by association and dissociation rates from RAS-GTP and by RAS-GTP concentration. The model further suggested that the relatively protracted activation of the RAF-MEK1/2-ERK1/2 module, in comparison with RAF1 membrane localization, may involve multiple rounds of cytosolic RAF1 rebinding to active RAS at the membrane.
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Affiliation(s)
- Sachin V Surve
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Paul J Myers
- Department of Chemical Engineering, University of Virginia, Charlottesville, VA 22904
| | - Samantha A Clayton
- Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22904
| | - Simon C Watkins
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
| | - Matthew J Lazzara
- Department of Chemical Engineering, University of Virginia, Charlottesville, VA 22904.,Department of Biomedical Engineering, University of Virginia, Charlottesville, VA 22904
| | - Alexander Sorkin
- Department of Cell Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261
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20
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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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21
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Hoang KV, Rajaram MVS, Curry HM, Gavrilin MA, Wewers MD, Schlesinger LS. Complement Receptor 3-Mediated Inhibition of Inflammasome Priming by Ras GTPase-Activating Protein During Francisella tularensis Phagocytosis by Human Mononuclear Phagocytes. Front Immunol 2018; 9:561. [PMID: 29632532 PMCID: PMC5879101 DOI: 10.3389/fimmu.2018.00561] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 03/06/2018] [Indexed: 01/08/2023] Open
Abstract
Francisella tularensis is a remarkably infectious facultative intracellular bacterium of macrophages that causes tularemia. Early evasion of host immune responses contributes to the success of F. tularensis as a pathogen. F. tularensis entry into human monocytes and macrophages is mediated by the major phagocytic receptor, complement receptor 3 (CR3, CD11b/CD18). We recently determined that despite a significant increase in macrophage uptake following C3 opsonization of the virulent Type A F. tularensis spp. tularensis Schu S4, this phagocytic pathway results in limited pro-inflammatory cytokine production. Notably, MAP kinase/ERK activation is suppressed immediately during C3-opsonized Schu S4-CR3 phagocytosis. A mathematical model of CR3-TLR2 crosstalk predicted early involvement of Ras GTPase-activating protein (RasGAP) in immune suppression by CR3. Here, we link CR3-mediated uptake of opsonized Schu S4 by human monocytes and macrophages with inhibition of early signal 1 inflammasome activation, evidenced by limited caspase-1 cleavage and IL-18 release. This inhibition is due to increased RasGAP activity, leading to a reduction in the Ras-ERK signaling cascade upstream of the early inflammasome activation event. Thus, our data uncover a novel signaling pathway mediated by CR3 following engagement of opsonized virulent F. tularensis to limit inflammasome activation in human phagocytic cells, thereby contributing to evasion of the host innate immune system.
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Affiliation(s)
- Ky V Hoang
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States
| | - Murugesan V S Rajaram
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States
| | - Heather Marie Curry
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States
| | - Mikhail A Gavrilin
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Internal Medicine, Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Mark D Wewers
- Division of Pulmonary, Allergy, Critical Care and Sleep Medicine, Department of Internal Medicine, Davis Heart & Lung Research Institute, The Ohio State University, Columbus, OH, United States
| | - Larry S Schlesinger
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, OH, United States.,Texas Biomedical Research Institute, San Antonio, TX, United States
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22
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Nakamura Y, Umeki N, Abe M, Sako Y. Mutation-Specific Mechanisms of Hyperactivation of Noonan Syndrome SOS Molecules Detected with Single-molecule Imaging in Living Cells. Sci Rep 2017; 7:14153. [PMID: 29074966 PMCID: PMC5658395 DOI: 10.1038/s41598-017-14190-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2017] [Accepted: 10/04/2017] [Indexed: 11/30/2022] Open
Abstract
Noonan syndrome (NS) is a congenital hereditary disorder associated with developmental and cardiac defects. Some patients with NS carry mutations in SOS, a guanine nucleotide exchange factor (GEF) for the small GTPase RAS. NS mutations have been identified not only in the GEF domain, but also in various domains of SOS, suggesting that multiple mechanisms disrupt SOS function. In this study, we examined three NS mutations in different domains of SOS to clarify the abnormality in its translocation to the plasma membrane, where SOS activates RAS. The association and dissociation kinetics between SOS tagged with a fluorescent protein and the living cell surface were observed in single molecules. All three mutants showed increased affinity for the plasma membrane, inducing excessive RAS signalling. However, the mechanisms by which their affinity was increased were specific to each mutant. Conformational disorder in the resting state, increased probability of a conformational change on the plasma membrane, and an increased association rate constant with the membrane receptor are the suggested mechanisms. These different properties cause the specific phenotypes of the mutants, which should be rescuable with different therapeutic strategies. Therefore, single-molecule kinetic analyses of living cells are useful for the pathological analysis of genetic diseases.
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Affiliation(s)
- Yuki Nakamura
- Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, 351-0198, Japan
| | - Nobuhisa Umeki
- Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, 351-0198, Japan
| | - Mitsuhiro Abe
- Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, 351-0198, Japan
| | - Yasushi Sako
- Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, 351-0198, Japan.
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23
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Iino R, Iida T, Nakamura A, Saita EI, You H, Sako Y. Single-molecule imaging and manipulation of biomolecular machines and systems. Biochim Biophys Acta Gen Subj 2017; 1862:241-252. [PMID: 28789884 DOI: 10.1016/j.bbagen.2017.08.008] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 07/23/2017] [Accepted: 08/03/2017] [Indexed: 02/08/2023]
Abstract
BACKGROUND Biological molecular machines support various activities and behaviors of cells, such as energy production, signal transduction, growth, differentiation, and migration. SCOPE OF REVIEW We provide an overview of single-molecule imaging methods involving both small and large probes used to monitor the dynamic motions of molecular machines in vitro (purified proteins) and in living cells, and single-molecule manipulation methods used to measure the forces, mechanical properties and responses of biomolecules. We also introduce several examples of single-molecule analysis, focusing primarily on motor proteins and signal transduction systems. MAJOR CONCLUSIONS Single-molecule analysis is a powerful approach to unveil the operational mechanisms both of individual molecular machines and of systems consisting of many molecular machines. GENERAL SIGNIFICANCE Quantitative, high-resolution single-molecule analyses of biomolecular systems at the various hierarchies of life will help to answer our fundamental question: "What is life?" This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato.
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Affiliation(s)
- Ryota Iino
- Okazaki Institute for Integrative Bioscience, Institute for Molecular Science, National Institutes of Natural Sciences, Japan; Department of Functional Molecular Science, School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Japan.
| | - Tatsuya Iida
- Okazaki Institute for Integrative Bioscience, Institute for Molecular Science, National Institutes of Natural Sciences, Japan; Department of Functional Molecular Science, School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Japan
| | - Akihiko Nakamura
- Okazaki Institute for Integrative Bioscience, Institute for Molecular Science, National Institutes of Natural Sciences, Japan; Department of Functional Molecular Science, School of Physical Sciences, The Graduate University for Advanced Studies (SOKENDAI), Japan
| | - Ei-Ichiro Saita
- Information Processing Biology Unit, Okinawa Institute of Science and Technology Graduate University, Japan
| | - Huijuan You
- School of Pharmacy, Tongji Medical College, Huazhong University of Science and Technology, China.
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24
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Yoshizawa R, Umeki N, Yanagawa M, Murata M, Sako Y. Single-molecule fluorescence imaging of RalGDS on cell surfaces during signal transduction from Ras to Ral. Biophys Physicobiol 2017; 14:75-84. [PMID: 28744424 PMCID: PMC5515350 DOI: 10.2142/biophysico.14.0_75] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 04/29/2017] [Indexed: 01/28/2023] Open
Abstract
RalGDS is one of the Ras effectors and functions as a guanine nucleotide exchange factor for the small G-protein, Ral, which regulates membrane trafficking and cytoskeletal remodeling. The translocation of RalGDS from the cytoplasm to the plasma membrane is required for Ral activation. In this study, to understand the mechanism of Ras–Ral signaling we performed a single-molecule fluorescence analysis of RalGDS and its functional domains (RBD and REMCDC) on the plasma membranes of living HeLa cells. Increased molecular density of RalGDS and RBD, but not REMCDC, was observed on the plasma membrane after EGF stimulation of the cells to induce Ras activation, suggesting that the translocation of RalGDS involves an interaction between the GTP-bound active form of Ras and the RBD of RalGDS. Whereas the RBD played an important role in increasing the association rate constant between RalGDS and the plasma membrane, the REMCDC domain affected the dissociation rate constant from the membrane, which decreased after Ras activation or the hyperexpression of Ral. The Y64 residue of Ras and clusters of RalGDS molecules were involved in this reduction. From these findings, we infer that Ras activation not merely increases the cell-surface density of RalGDS, but actively stimulates the RalGDS–Ral interaction through a structural change in RalGDS and/or the accumulation of Ral, as well as the GTP–Ras/RalGDS clusters, to induce the full activation of Ral.
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Affiliation(s)
- Ryo Yoshizawa
- Cellular Informatics Lab., RIKEN, Wako, Saitama 351-0198, Japan.,Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Nobuhisa Umeki
- Cellular Informatics Lab., RIKEN, Wako, Saitama 351-0198, Japan
| | | | - Masayuki Murata
- Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Meguro-ku, Tokyo 153-8902, Japan
| | - Yasushi Sako
- Cellular Informatics Lab., RIKEN, Wako, Saitama 351-0198, Japan
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25
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Modeling Cellular Noise Underlying Heterogeneous Cell Responses in the Epidermal Growth Factor Signaling Pathway. PLoS Comput Biol 2016; 12:e1005222. [PMID: 27902699 PMCID: PMC5130170 DOI: 10.1371/journal.pcbi.1005222] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2016] [Accepted: 10/25/2016] [Indexed: 12/03/2022] Open
Abstract
Cellular heterogeneity, which plays an essential role in biological phenomena, such as drug resistance and migration, is considered to arise from intrinsic (i.e., reaction kinetics) and extrinsic (i.e., protein variability) noise in the cell. However, the mechanistic effects of these types of noise to determine the heterogeneity of signal responses have not been elucidated. Here, we report that the output of epidermal growth factor (EGF) signaling activity is modulated by cellular noise, particularly by extrinsic noise of particular signaling components in the pathway. We developed a mathematical model of the EGF signaling pathway incorporating regulation between extracellular signal-regulated kinase (ERK) and nuclear pore complex (NPC), which is necessary for switch-like activation of the nuclear ERK response. As the threshold of switch-like behavior is more sensitive to perturbations than the graded response, the effect of biological noise is potentially critical for cell fate decision. Our simulation analysis indicated that extrinsic noise, but not intrinsic noise, contributes to cell-to-cell heterogeneity of nuclear ERK. In addition, we accurately estimated variations in abundance of the signal proteins between individual cells by direct comparison of experimental data with simulation results using Apparent Measurement Error (AME). AME was constant regardless of whether the protein levels varied in a correlated manner, while covariation among proteins influenced cell-to-cell heterogeneity of nuclear ERK, suppressing the variation. Simulations using the estimated protein abundances showed that each protein species has different effects on cell-to-cell variation in the nuclear ERK response. In particular, variability of EGF receptor, Ras, Raf, and MEK strongly influenced cellular heterogeneity, while others did not. Overall, our results indicated that cellular heterogeneity in response to EGF is strongly driven by extrinsic noise, and that such heterogeneity results from variability of particular protein species that function as sensitive nodes, which may contribute to the pathogenesis of human diseases. Individual cell behaviors are controlled by a variety of noise, such as fluctuations in biochemical reactions, protein variability, molecular diffusion, transcriptional noise, cell-to-cell contact, temperature, and pH. Such cellular noise often interferes with signal responses from external stimuli, and such heterogeneity functions in induction of drug resistance, survival, and migration of cells. Thus, heterogeneous cellular responses have positive and negative roles. However, the regulatory mechanisms that produce cellular heterogeneity are unclear. By mathematical modeling and simulations, we investigated how heterogeneous signaling responses are evoked in the EGF signaling pathway and influence the switch-like activation of nuclear ERK. This study demonstrated that cellular heterogeneity of the EGF signaling response is evoked by cell-to-cell variation of particular signaling proteins, such as EGFR, Ras, Raf, and MEK, which act as sensitive nodes in the pathway. These results suggest that signaling responses in individual cells can be predicted from the levels of proteins of sensitive nodes. This study also suggested that proteins of sensitive nodes may serve as cell survival mechanisms.
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Unravelling the Mechanism of TrkA-Induced Cell Death by Macropinocytosis in Medulloblastoma Daoy Cells. Mol Cell Biol 2016; 36:2596-611. [PMID: 27503856 DOI: 10.1128/mcb.00255-16] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Accepted: 07/29/2016] [Indexed: 12/26/2022] Open
Abstract
Macropinocytosis is a normal cellular process by which cells internalize extracellular fluids and nutrients from their environment and is one strategy that Ras-transformed pancreatic cancer cells use to increase uptake of amino acids to meet the needs of rapid growth. Paradoxically, in non-Ras transformed medulloblastoma brain tumors, we have shown that expression and activation of the receptor tyrosine kinase TrkA overactivates macropinocytosis, resulting in the catastrophic disintegration of the cell membrane and in tumor cell death. The molecular basis of this uncontrolled form of macropinocytosis has not been previously understood. Here, we demonstrate that the overactivation of macropinocytosis is caused by the simultaneous activation of two TrkA-mediated pathways: (i) inhibition of RhoB via phosphorylation at Ser(185) by casein kinase 1, which relieves actin stress fibers, and (ii) FRS2-scaffolded Src and H-Ras activation of RhoA, which stimulate actin reorganization and the formation of lamellipodia. Since catastrophic macropinocytosis results in brain tumor cell death, improved understanding of the mechanisms involved will facilitate future efforts to reprogram tumors, even those resistant to apoptosis, to die.
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27
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Affiliation(s)
- Ruth Nussinov
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Chung-Jung Tsai
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
| | - Hyunbum Jang
- Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
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Nakamura Y, Hibino K, Yanagida T, Sako Y. Switching of the positive feedback for RAS activation by a concerted function of SOS membrane association domains. Biophys Physicobiol 2016; 13:1-11. [PMID: 27924253 PMCID: PMC5042160 DOI: 10.2142/biophysico.13.0_1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 12/11/2015] [Indexed: 01/12/2023] Open
Abstract
Son of sevenless (SOS) is a guanine nucleotide exchange factor that regulates cell behavior by activating the small GTPase RAS. Recent in vitro studies have suggested that an interaction between SOS and the GTP-bound active form of RAS generates a positive feedback loop that propagates RAS activation. However, it remains unclear how the multiple domains of SOS contribute to the regulation of the feedback loop in living cells. Here, we observed single molecules of SOS in living cells to analyze the kinetics and dynamics of SOS behavior. The results indicate that the histone fold and Grb2-binding domains of SOS concertedly produce an intermediate state of SOS on the cell surface. The fraction of the intermediated state was reduced in positive feedback mutants, suggesting that the feedback loop functions during the intermediate state. Translocation of RAF, recognizing the active form of RAS, to the cell surface was almost abolished in the positive feedback mutants. Thus, the concerted functions of multiple membrane-associating domains of SOS governed the positive feedback loop, which is crucial for cell fate decision regulated by RAS.
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Affiliation(s)
- Yuki Nakamura
- Cellular Informatics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan; Nanobiology Laboratories, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kayo Hibino
- Laboratory for Cell Signaling Dynamics, RIKEN QBiC, Suita, Osaka 565-0874, Japan
| | - Toshio Yanagida
- Nanobiology Laboratories, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
| | - Yasushi Sako
- Cellular Informatics Laboratory, RIKEN, Wako, Saitama 351-0198, Japan; Nanobiology Laboratories, Graduate School of Frontier Biosciences, Osaka University, Suita, Osaka 565-0871, Japan
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29
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Kanda Y, Satoh R, Matsumoto S, Ikeda C, Inutsuka N, Hagihara K, Matzno S, Tsujimoto S, Kita A, Sugiura R. Skb5, an SH3 adaptor protein, regulates Pmk1 MAPK signaling by controlling the intracellular localization of Mkh1 MAPKKK. J Cell Sci 2016; 129:3189-202. [DOI: 10.1242/jcs.188854] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 07/06/2016] [Indexed: 11/20/2022] Open
Abstract
The MAPK cascade is a highly conserved signaling module composed of MAPK/MAPKK/MAPKKK. MAPKKK Mkh1 is an initiating kinase in Pmk1 MAPK signaling, which regulates cell integrity in fission yeast. Our genetic screen for regulators of Pmk1 signaling identified Skb5 (Shk1 kinase binding protein 5), an SH3 domain-containing adaptor protein. Here, we showed that Skb5 serves as an inhibitor of Pmk1 MAPK signaling activation by downregulating Mkh1 localization to cell tips via its interaction with the SH3 domain. Consistently, the Mkh13PA mutant protein, with impaired Skb5 binding, remained in the cell tips, even when Skb5 was overproduced. Intriguingly, Skb5 needs Mkh1 to localize to the growing ends as Mkh1 deletion and disruption of Mkh1 binding impairs Skb5 localization. Deletion of Pck2, an upstream activator of Mkh1, impaired the cell tip localization of Mkh1 and Skb5 as well as Mkh1/Skb5 interaction. Interestingly, both Pck2 and Mkh1 localized to the cell tips at the G1/S phase, which coincided with Pmk1 MAPK activation. Altogether, Mkh1 localization to cell tips is important for transmitting upstream signaling to Pmk1 and Skb5 spatially regulates this process.
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Affiliation(s)
- Yuki Kanda
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Japan
| | - Ryosuke Satoh
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Japan
| | - Saki Matsumoto
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Japan
| | - Chisato Ikeda
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Japan
| | - Natsumi Inutsuka
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Japan
| | - Kanako Hagihara
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Japan
| | - Sumio Matzno
- Division of Pharmaceutical Education, Faculty of Pharmacy, Kinki University, Japan
| | - Sho Tsujimoto
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Japan
| | - Ayako Kita
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Japan
| | - Reiko Sugiura
- Laboratory of Molecular Pharmacogenomics, School of Pharmaceutical Sciences, Kinki University, Japan
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30
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An S, Yang Y, Ward R, Liu Y, Guo XX, Xu TR. A-Raf: A new star of the family of raf kinases. Crit Rev Biochem Mol Biol 2015; 50:520-31. [PMID: 26508523 DOI: 10.3109/10409238.2015.1102858] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The Ras-Raf-MEK-MAPK (mitogen-activated protein kinase)-signaling pathway plays a key role in the regulation of many cellular functions, including cell proliferation, differentiation and transformation, by transmitting signals from membrane receptors to various cytoplasmic and nuclear targets. One of the key components of this pathway is the serine/threonine protein kinase, Raf. The Raf family kinases (A-Raf, B-Raf and C-Raf) have been intensively studied since being identified in the early 1980s as retroviral oncogenes, especially with respect to the discovery of activating mutations of B-Raf in a large number of tumors which led to intensified efforts to develop drugs targeting Raf kinases. This also resulted in a rapid increase in our knowledge of the biological functions of the B-Raf and C-Raf isoforms, which may in turn be contrasted with the little that is known about A-Raf. The biological functions of A-Raf remain mysterious, although it appears to share some of the basic properties of the other two isoforms. Recently, emerging evidence has begun to reveal the functions of A-Raf, of which some are kinase-independent. These include the inhibition of apoptosis by binding to MST2, acting as safeguard against oncogenic transformation by suppressing extracellular signal-regulated kinases (ERK) activation and playing a role in resistance to Raf inhibitors. In this review, we discuss the regulation of A-Raf protein expression, and the roles of A-Raf in apoptosis and cancer, with a special focus on its role in resistance to Raf inhibitors. We also describe the scaffold functions of A-Raf and summarize the unexpected complexity of Raf signaling.
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Affiliation(s)
- Su An
- a Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan , China and
| | - Yang Yang
- a Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan , China and
| | - Richard Ward
- b Molecular Pharmacology Group, Institute of Molecular, Cell and Systems Biology, College of Medical, Veterinary and Life Sciences, University of Glasgow , Scotland , UK
| | - Ying Liu
- a Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan , China and
| | - Xiao-Xi Guo
- a Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan , China and
| | - Tian-Rui Xu
- a Faculty of Life Science and Technology , Kunming University of Science and Technology , Kunming , Yunnan , China and
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31
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Chavan TS, Muratcioglu S, Marszalek R, Jang H, Keskin O, Gursoy A, Nussinov R, Gaponenko V. Plasma membrane regulates Ras signaling networks. CELLULAR LOGISTICS 2015; 5:e1136374. [PMID: 27054048 PMCID: PMC4820813 DOI: 10.1080/21592799.2015.1136374] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 12/17/2015] [Indexed: 12/31/2022]
Abstract
Ras GTPases activate more than 20 signaling pathways, regulating such essential cellular functions as proliferation, survival, and migration. How Ras proteins control their signaling diversity is still a mystery. Several pieces of evidence suggest that the plasma membrane plays a critical role. Among these are: (1) selective recruitment of Ras and its effectors to particular localities allowing access to Ras regulators and effectors; (2) specific membrane-induced conformational changes promoting Ras functional diversity; and (3) oligomerization of membrane-anchored Ras to recruit and activate Raf. Taken together, the membrane does not only attract and retain Ras but also is a key regulator of Ras signaling. This can already be gleaned from the large variability in the sequences of Ras membrane targeting domains, suggesting that localization, environment and orientation are important factors in optimizing the function of Ras isoforms.
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Affiliation(s)
- Tanmay Sanjeev Chavan
- Department of Medicinal Chemistry; University of Illinois at Chicago; Chicago, IL USA
| | - Serena Muratcioglu
- Center for Computational Biology and Bioinformatics; Koc University; Istanbul, Turkey
| | - Richard Marszalek
- Department of Biochemistry and Molecular Genetics; University of Illinois at Chicago; Chicago, IL USA
| | - Hyunbum Jang
- Cancer and Inflammation Program; Basic Science Program; Leidos Biomedical Research, Inc.; Frederick National Laboratory for Cancer Research; National Cancer Institute at Frederick; Frederick, MD USA
| | - Ozlem Keskin
- Center for Computational Biology and Bioinformatics; Koc University; Istanbul, Turkey
| | - Attila Gursoy
- Center for Computational Biology and Bioinformatics; Koc University; Istanbul, Turkey
| | - Ruth Nussinov
- Cancer and Inflammation Program; Basic Science Program; Leidos Biomedical Research, Inc.; Frederick National Laboratory for Cancer Research; National Cancer Institute at Frederick; Frederick, MD USA
- Sackler Institute of Molecular Medicine; Department of Human Genetics and Molecular Medicine; Sackler School of Medicine; Tel Aviv University; Tel Aviv, Israel
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics; University of Illinois at Chicago; Chicago, IL USA
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Zhou Y, Mao H, Joddar B, Umeki N, Sako Y, Wada KI, Nishioka C, Takahashi E, Wang Y, Ito Y. The significance of membrane fluidity of feeder cell-derived substrates for maintenance of iPS cell stemness. Sci Rep 2015; 5:11386. [PMID: 26065582 PMCID: PMC4464345 DOI: 10.1038/srep11386] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 04/22/2015] [Indexed: 11/09/2022] Open
Abstract
The biological activity of cell-derived substrates to maintain undifferentiated murine-induced pluripotent stem (iPS) cells was correlated to membrane fluidity as a new parameter of cell culture substrates. Murine embryonic fibroblasts (MEFs) were employed as feeder cells and their membrane fluidity was tuned by chemical fixation using formaldehyde (FA). Membrane fluidity was evaluated by real-time single-molecule observations of green fluorescent protein-labeled epidermal growth factor receptors on chemically fixed MEFs. Biological activity was monitored by colony formation of iPS cells. Treatment with a low concentration of FA sustained the membrane fluidity and biological activity, which were comparable to those of mitomycin C-treated MEFs. The biological activity was further confirmed by sustained expression of alkaline phosphatase, SSEA-1, and other pluripotency markers in iPS cells after 3-5 days of culture on FA-fixed MEFs. Chemical fixation of feeder cells has several advantages such as providing ready-to-use culture substrates without contamination by proliferating feeder cells. Therefore, our results provide an important basis for the development of chemically fixed culture substrates for pluripotent stem cell culture as an alternative to conventional treatment by mitomycin C or x-ray irradiation.
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Affiliation(s)
- Yue Zhou
- Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- School of Nursing, Nanjing University of Chinese Medicine, 138 Xianlin Road, Qixia District, Nanjing, Jiangsu Province 210023, China
- Department of Regenerative Medicine, School of Pharmaceutical Science, Jilin University, No.1266 Fujin Road, Changchun 130021, China
| | - Hongli Mao
- Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Binata Joddar
- Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Nobuhisa Umeki
- Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yasushi Sako
- Cellular Informatics Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Ken-Ichi Wada
- Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Chieko Nishioka
- Support Unit for Animal Experiment, Research Resources Center, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Eiki Takahashi
- Support Unit for Animal Experiment, Research Resources Center, RIKEN Brain Science Institute, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yi Wang
- Department of Regenerative Medicine, School of Pharmaceutical Science, Jilin University, No.1266 Fujin Road, Changchun 130021, China
| | - Yoshihiro Ito
- Nano Medical Engineering Laboratory, RIKEN, 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
- Emergent Bioengineering Materials Research Team, RIKEN Center for Emergent Matter Science, 2-1Hirosawa, Wako, Saitama 351-0198, Japan
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33
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Maeda R, Hiroshima M, Yamashita T, Wada A, Nishimura S, Sako Y, Shichida Y, Imamoto Y. Single-molecule observation of the ligand-induced population shift of rhodopsin, a G-protein-coupled receptor. Biophys J 2014; 106:915-24. [PMID: 24559994 DOI: 10.1016/j.bpj.2014.01.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Revised: 12/26/2013] [Accepted: 01/10/2014] [Indexed: 01/20/2023] Open
Abstract
Rhodopsin is a G-protein-coupled receptor, in which retinal chromophore acts as inverse-agonist or agonist depending on its configuration and protonation state. Photostimulation of rhodopsin results in a pH-dependent equilibrium between the active state (Meta-II) and its inactive precursor (Meta-I). Here, we monitored conformational changes of rhodopsin using a fluorescent probe Alexa594 at the cytoplasmic surface, which shows fluorescence increase upon the generation of active state, by single-molecule measurements. The fluorescence intensity of a single photoactivated rhodopsin molecule alternated between two states. Interestingly, such a fluorescence alternation was also observed for ligand-free rhodopsin (opsin), but not for dark-state rhodopsin. In addition, the pH-dependences of Meta-I/Meta-II equilibrium estimated by fluorescence measurements deviated notably from estimates based on absorption spectra, indicating that both Meta-I and Meta-II are mixtures of two conformers. Our observations indicate that rhodopsin molecules intrinsically adopt both active and inactive conformations, and the ligand retinal shifts the conformational equilibrium. These findings provide dynamical insights into the activation mechanisms of G-protein-coupled receptors.
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Affiliation(s)
- Ryo Maeda
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Michio Hiroshima
- Cellular Informatics Laboratory, RIKEN, Wako, Japan; Laboratory for Cell Signaling Dynamics, RIKEN Quantitative Biology Center, Furuedai, Suita, Japan
| | - Takahiro Yamashita
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Akimori Wada
- Department of Organic Chemistry for Life Science, Kobe Pharmaceutical University, Kobe, Japan
| | - Shoko Nishimura
- Cellular and Structural Physiology Institute, Nagoya University, Nagoya, Japan
| | - Yasushi Sako
- Cellular Informatics Laboratory, RIKEN, Wako, Japan
| | - Yoshinori Shichida
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan
| | - Yasushi Imamoto
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto, Japan.
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34
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Src promotes GTPase activity of Ras via tyrosine 32 phosphorylation. Proc Natl Acad Sci U S A 2014; 111:E3785-94. [PMID: 25157176 DOI: 10.1073/pnas.1406559111] [Citation(s) in RCA: 74] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mutations in Ras GTPase and various other components of the Ras signaling pathways are among the most common genetic alterations in human cancers and also have been identified in several familial developmental syndromes. Over the past few decades it has become clear that the activity or the oncogenic potential of Ras is dependent on the nonreceptor tyrosine kinase Src to promote the Ras/Raf/MAPK pathway essential for proliferation, differentiation, and survival of eukaryotic cells. However, no direct relationship between Ras and Src has been established. We show here that Src binds to and phosphorylates GTP-, but not GDP-, loaded Ras on a conserved Y32 residue within the switch I region in vitro and that in vivo, Ras-Y32 phosphorylation markedly reduces the binding to effector Raf and concomitantly increases binding to GTPase-activating proteins and the rate of GTP hydrolysis. These results suggest that, in the context of predetermined crystallographic structures, Ras-Y32 serves as an Src-dependent keystone regulatory residue that modulates Ras GTPase activity and ensures unidirectionality to the Ras GTPase cycle.
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35
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Real-time single-molecule co-immunoprecipitation analyses reveal cancer-specific Ras signalling dynamics. Nat Commun 2013; 4:1505. [PMID: 23422673 PMCID: PMC3586730 DOI: 10.1038/ncomms2507] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2012] [Accepted: 01/16/2013] [Indexed: 01/07/2023] Open
Abstract
Co-immunoprecipitation (co-IP) has become a standard technique, but its protein-band output provides only static, qualitative information about protein–protein interactions. Here we demonstrate a real-time single-molecule co-IP technique that generates real-time videos of individual protein–protein interactions as they occur in unpurified cell extracts. By analysing single Ras–Raf interactions with a 50-ms time resolution, we have observed transient intermediates of the protein–protein interaction and determined all the essential kinetic rates. Using this technique, we have quantified the active fraction of native Ras proteins in xenograft tumours, normal tissue and cancer cell lines. We demonstrate that the oncogenic Ras mutations selectively increase the active-Ras fraction by one order of magnitude, without affecting total Ras levels or single-molecule signalling kinetics. Our approach allows us to probe the previously hidden, dynamic aspects of weak protein–protein interactions. It also suggests a path forward towards precision molecular diagnostics at the protein–protein interaction level. Co-immunoprecipitation provides static and qualitative information about protein–protein interactions. Lee et al. create real-time movies of single protein–protein interactions during co-immunoprecipitation, and use them to assess the dynamics of mutant Ras proteins derived from tumours.
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36
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Matsuoka S, Shibata T, Ueda M. Asymmetric PTEN distribution regulated by spatial heterogeneity in membrane-binding state transitions. PLoS Comput Biol 2013; 9:e1002862. [PMID: 23326224 PMCID: PMC3542079 DOI: 10.1371/journal.pcbi.1002862] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2012] [Accepted: 11/10/2012] [Indexed: 11/18/2022] Open
Abstract
The molecular mechanisms that underlie asymmetric PTEN distribution at the posterior of polarized motile cells and regulate anterior pseudopod formation were addressed by novel single-molecule tracking analysis. Heterogeneity in the lateral mobility of PTEN on a membrane indicated the existence of three membrane-binding states with different diffusion coefficients and membrane-binding lifetimes. The stochastic state transition kinetics of PTEN among these three states were suggested to be regulated spatially along the cell polarity such that only the stable binding state is selectively suppressed at the anterior membrane to cause local PTEN depletion. By incorporating experimentally observed kinetic parameters into a simple mathematical model, the asymmetric PTEN distribution can be explained quantitatively to illustrate the regulatory mechanisms for cellular asymmetry based on an essential causal link between individual stochastic reactions and stable localizations of the ensemble.
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Affiliation(s)
- Satomi Matsuoka
- Laboratory for Cell Signaling Dynamics, RIKEN Quantitative Biology Center, Suita, Japan
- Laboratories for Nanobiology, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
- CREST, Japan Science and Technology Agency (JST), Suita, Japan
| | - Tatsuo Shibata
- CREST, Japan Science and Technology Agency (JST), Suita, Japan
- Laboratories for Physical Biology, RIKEN Center for Developmental Biology, Kobe, Japan
| | - Masahiro Ueda
- Laboratory for Cell Signaling Dynamics, RIKEN Quantitative Biology Center, Suita, Japan
- Laboratories for Nanobiology, Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
- CREST, Japan Science and Technology Agency (JST), Suita, Japan
- Laboratory of Single Molecule Biology, Department of Biological Sciences, Graduate School of Science, Osaka University, Toyonaka, Japan
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37
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Leander R, Dai S, Schlesinger LS, Friedman A. A mathematical model of CR3/TLR2 crosstalk in the context of Francisella tularensis infection. PLoS Comput Biol 2012; 8:e1002757. [PMID: 23133361 PMCID: PMC3486853 DOI: 10.1371/journal.pcbi.1002757] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 09/05/2012] [Indexed: 02/04/2023] Open
Abstract
Complement Receptor 3 (CR3) and Toll-like Receptor 2 (TLR2) are pattern recognition receptors expressed on the surface of human macrophages. Although these receptors are essential components for recognition by the innate immune system, pathogen coordinated crosstalk between them can suppress the production of protective cytokines and promote infection. Recognition of the virulent Schu S4 strain of the intracellular pathogen Francisella tularensis by host macrophages involves CR3/TLR2 crosstalk. Although experimental data provide evidence that Lyn kinase and PI3K are essential components of the CR3 pathway that influences TLR2 activity, additional responsible upstream signaling components remain unknown. In this paper we construct a mathematical model of CR3 and TLR2 signaling in response to F. tularensis. After demonstrating that the model is consistent with experimental results we perform numerical simulations to evaluate the contributions that Akt and Ras-GAP make to ERK inhibition. The model confirms that phagocytosis-associated changes in the composition of the cell membrane can inhibit ERK activity and predicts that Akt and Ras-GAP synergize to inhibit ERK.
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Affiliation(s)
- Rachel Leander
- Mathematical Biosciences Institute, The Ohio State University, Columbus, Ohio, United States of America
| | - Shipan Dai
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, United States of America
| | - Larry S. Schlesinger
- Center for Microbial Interface Biology, Department of Microbial Infection and Immunity, The Ohio State University, Columbus, Ohio, United States of America
| | - Avner Friedman
- Mathematical Biosciences Institute, The Ohio State University, Columbus, Ohio, United States of America
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