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Zhou C, Fan Z, Gu Y, Ge Z, Tao Z, Cui R, Li Y, Zhou G, Huo R, Gao M, Wang D, He W, Zheng M, Zhang S, Xu T. Design, Synthesis, and Biological Evaluation of Potent and Selective PROTAC Degraders of Oncogenic KRAS G12D. J Med Chem 2024; 67:1147-1167. [PMID: 38197882 DOI: 10.1021/acs.jmedchem.3c01622] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
KRASG12D, the most frequent KRAS oncogenic mutation, is a promising target for cancer therapy. Herein, we report the design, synthesis, and biological evaluation of a series of KRASG12D PROTACs by connecting the analogues of MRTX1133 and the VHL ligand. Structural modifications of the linker moiety and KRAS inhibitor part suggested a critical role of membrane permeability in the degradation activity of the KRASG12D PROTACs. Mechanism studies with the representative compound 8o demonstrated that the potent, rapid, and selective degradation of KRASG12D induced by 8o was via a VHL- and proteasome-dependent manner. This compound selectively and potently suppressed the growth of multiple KRASG12D mutant cancer cells, displayed favorable pharmacokinetic and pharmacodynamic properties in mice, and showed significant antitumor efficacy in the AsPC-1 xenograft mouse model. Further optimization of 8o appears to be promising for the development of a new chemotherapy for KRASG12D-driven cancers as the complementary therapeutic strategy to KRAS inhibition.
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Affiliation(s)
- Chuan Zhou
- Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Zisheng Fan
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Lingang Laboratory, Shanghai 200031, China
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Yuejiao Gu
- Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
| | - Zhiming Ge
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Zhaofan Tao
- Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
| | - Rongrong Cui
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Yupeng Li
- Department of Pharmaceutical Sciences, School of Pharmacy and Border Biomedical Research Center, The University of Texas at EI Paso, EI Paso, Texas 79902, United States
| | - Guizhen Zhou
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Lingang Laboratory, Shanghai 200031, China
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Ruifeng Huo
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Mingshan Gao
- Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Dan Wang
- School of Chinese Materia Medica, Nanjing University of Chinese Medicine, Nanjing 210023, China
| | - Wei He
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
- Nanchang University, Nanchang 330031, China
| | - Mingyue Zheng
- Shanghai Institute for Advanced Immunochemical Studies and School of Life Science and Technology, ShanghaiTech University, Shanghai 201210, China
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
| | - Sulin Zhang
- Drug Discovery and Design Center, State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
| | - Tianfeng Xu
- Department of Medicinal Chemistry, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zuchongzhi Road, Shanghai 201203, China
- University of Chinese Academy of Sciences, 19 Yuquan Road, Beijing 100049, China
- School of Pharmaceutical Science and Technology, Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou 310024, China
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Nussinov R, Liu Y, Zhang W, Jang H. Protein conformational ensembles in function: roles and mechanisms. RSC Chem Biol 2023; 4:850-864. [PMID: 37920394 PMCID: PMC10619138 DOI: 10.1039/d3cb00114h] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Accepted: 09/02/2023] [Indexed: 11/04/2023] Open
Abstract
The sequence-structure-function paradigm has dominated twentieth century molecular biology. The paradigm tacitly stipulated that for each sequence there exists a single, well-organized protein structure. Yet, to sustain cell life, function requires (i) that there be more than a single structure, (ii) that there be switching between the structures, and (iii) that the structures be incompletely organized. These fundamental tenets called for an updated sequence-conformational ensemble-function paradigm. The powerful energy landscape idea, which is the foundation of modernized molecular biology, imported the conformational ensemble framework from physics and chemistry. This framework embraces the recognition that proteins are dynamic and are always interconverting between conformational states with varying energies. The more stable the conformation the more populated it is. The changes in the populations of the states are required for cell life. As an example, in vivo, under physiological conditions, wild type kinases commonly populate their more stable "closed", inactive, conformations. However, there are minor populations of the "open", ligand-free states. Upon their stabilization, e.g., by high affinity interactions or mutations, their ensembles shift to occupy the active states. Here we discuss the role of conformational propensities in function. We provide multiple examples of diverse systems, including protein kinases, lipid kinases, and Ras GTPases, discuss diverse conformational mechanisms, and provide a broad outlook on protein ensembles in the cell. We propose that the number of molecules in the active state (inactive for repressors), determine protein function, and that the dynamic, relative conformational propensities, rather than the rigid structures, are the hallmark of cell life.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University Tel Aviv 69978 Israel
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Yonglan Liu
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Wengang Zhang
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research Frederick MD 21702 USA
- Cancer Innovation Laboratory, National Cancer Institute Frederick MD 21702 USA
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3
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Xie X, Yu T, Li X, Zhang N, Foster LJ, Peng C, Huang W, He G. Recent advances in targeting the "undruggable" proteins: from drug discovery to clinical trials. Signal Transduct Target Ther 2023; 8:335. [PMID: 37669923 PMCID: PMC10480221 DOI: 10.1038/s41392-023-01589-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 07/22/2023] [Accepted: 08/02/2023] [Indexed: 09/07/2023] Open
Abstract
Undruggable proteins are a class of proteins that are often characterized by large, complex structures or functions that are difficult to interfere with using conventional drug design strategies. Targeting such undruggable targets has been considered also a great opportunity for treatment of human diseases and has attracted substantial efforts in the field of medicine. Therefore, in this review, we focus on the recent development of drug discovery targeting "undruggable" proteins and their application in clinic. To make this review well organized, we discuss the design strategies targeting the undruggable proteins, including covalent regulation, allosteric inhibition, protein-protein/DNA interaction inhibition, targeted proteins regulation, nucleic acid-based approach, immunotherapy and others.
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Affiliation(s)
- Xin Xie
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Medical Technology and School of Pharmacy, Chengdu University of Traditional Chinese Medicine, 611137, Chengdu, China
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Tingting Yu
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Medical Technology and School of Pharmacy, Chengdu University of Traditional Chinese Medicine, 611137, Chengdu, China
| | - Xiang Li
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Medical Technology and School of Pharmacy, Chengdu University of Traditional Chinese Medicine, 611137, Chengdu, China
| | - Nan Zhang
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Medical Technology and School of Pharmacy, Chengdu University of Traditional Chinese Medicine, 611137, Chengdu, China
- Department of Dermatology and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, 610041, Chengdu, China
| | - Leonard J Foster
- Michael Smith Laboratories, University of British Columbia, Vancouver, BC, V6T 1Z4, Canada
| | - Cheng Peng
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Medical Technology and School of Pharmacy, Chengdu University of Traditional Chinese Medicine, 611137, Chengdu, China.
| | - Wei Huang
- State Key Laboratory of Southwestern Chinese Medicine Resources, College of Medical Technology and School of Pharmacy, Chengdu University of Traditional Chinese Medicine, 611137, Chengdu, China.
| | - Gu He
- Department of Dermatology and State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, 610041, Chengdu, China.
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Inhibition mechanism of MRTX1133 on KRAS G12D: a molecular dynamics simulation and Markov state model study. J Comput Aided Mol Des 2023; 37:157-166. [PMID: 36849761 DOI: 10.1007/s10822-023-00498-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Accepted: 02/11/2023] [Indexed: 03/01/2023]
Abstract
The mutant KRAS was considered as an "undruggable" target for decades, especially KRASG12D. It is a great challenge to develop the inhibitors for KRASG12D which lacks the thiol group for covalently binding ligands. The discovery of MRTX1133 solved the dilemma. Interestingly, MRTX1133 can bind to both the inactive and active states of KRASG12D. The binding mechanism of MRTX1133 with KRASG12D, especially how MRTX1133 could bind the active state KRASG12D without triggering the active function of KRASG12D, has not been fully understood. Here, we used a combination of all-atom molecular dynamics simulations and Markov state model (MSM) to understand the inhibition mechanism of MRTX1133 and its analogs. The stationary probabilities derived from MSM show that MRTX1133 and its analogs can stabilize the inactive or active states of KRASG12D into different conformations. More remarkably, by scrutinizing the conformational differences, MRTX1133 and its analogs were hydrogen bonded to Gly60 to stabilize the switch II region and left switch I region in a dynamically inactive conformation, thus achieving an inhibitory effect. Our simulation and analysis provide detailed inhibition mechanism of KRASG12D induced by MRTX1133 and its analogs. This study will provide guidance for future design of novel small molecule inhibitors of KRASG12D.
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GAP positions catalytic H-Ras residue Q61 for GTP hydrolysis in molecular dynamics simulations, complicating chemical rescue of Ras deactivation. Comput Biol Chem 2023; 104:107835. [PMID: 36893567 DOI: 10.1016/j.compbiolchem.2023.107835] [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: 02/01/2023] [Accepted: 02/16/2023] [Indexed: 03/05/2023]
Abstract
Functional interaction of Ras signaling proteins with upstream, negative regulatory GTPase activating proteins (GAPs) represents a crucial step in cellular decision making related to growth and survival. Key components of the catalytic transition state for Ras deactivation by GAP-accelerated hydrolysis of Ras-bound guanosine triphosphate (GTP) are thought to include an arginine residue from the GAP (the arginine finger), a glutamine residue from Ras (Q61), and a water molecule that is likely coordinated by Q61 to engage in nucleophilic attack on GTP. Here, we use in-vitro fluorescence experiments to show that 0.1-100 mM concentrations of free arginine, imidazole, and other small nitrogenous molecule fail to accelerate GTP hydrolysis, even in the presence of the catalytic domain of a mutant GAP lacking its arginine finger (R1276A NF1). This result is surprising given that imidazole can chemically rescue enzyme activity in arginine-to-alanine mutant protein tyrosine kinases (PTKs) that share many active site components with Ras/GAP complexes. Complementary all-atom molecular dynamics (MD) simulations reveal that an arginine finger GAP mutant still functions to enhance Ras Q61-GTP interaction, though less extensively than wild-type GAP. This increased Q61-GTP proximity may promote more frequent fluctuations into configurations that enable GTP hydrolysis as a component of the mechanism by which GAPs accelerate Ras deactivation in the face of arginine finger mutations. The failure of small molecule analogs of arginine to chemically rescue catalytic deactivation of Ras is consistent with the idea that the influence of the GAP goes beyond the simple provision of its arginine finger. However, the failure of chemical rescue in the presence of R1276A NF1 suggests that the GAPs arginine finger is either unsusceptible to rescue due to exquisite positioning or that it is involved in complex multivalent interactions. Therefore, in the context of oncogenic Ras proteins with mutations at codons 12 or 13 that inhibit arginine finger penetration toward GTP, drug-based chemical rescue of GTP hydrolysis may have bifunctional chemical/geometric requirements that are more difficult to satisfy than those that result from arginine-to-alanine mutations in other enzymes for which chemical rescue has been demonstrated.
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Nussinov R, Tsai CJ, Jang H. A New View of Activating Mutations in Cancer. Cancer Res 2022; 82:4114-4123. [PMID: 36069825 PMCID: PMC9664134 DOI: 10.1158/0008-5472.can-22-2125] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/16/2022] [Accepted: 09/01/2022] [Indexed: 12/14/2022]
Abstract
A vast effort has been invested in the identification of driver mutations of cancer. However, recent studies and observations call into question whether the activating mutations or the signal strength are the major determinant of tumor development. The data argue that signal strength determines cell fate, not the mutation that initiated it. In addition to activating mutations, factors that can impact signaling strength include (i) homeostatic mechanisms that can block or enhance the signal, (ii) the types and locations of additional mutations, and (iii) the expression levels of specific isoforms of genes and regulators of proteins in the pathway. Because signal levels are largely decided by chromatin structure, they vary across cell types, states, and time windows. A strong activating mutation can be restricted by low expression, whereas a weaker mutation can be strengthened by high expression. Strong signals can be associated with cell proliferation, but too strong a signal may result in oncogene-induced senescence. Beyond cancer, moderate signal strength in embryonic neural cells may be associated with neurodevelopmental disorders, and moderate signals in aging may be associated with neurodegenerative diseases, like Alzheimer's disease. The challenge for improving patient outcomes therefore lies in determining signaling thresholds and predicting signal strength.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, NCI, Frederick, Maryland
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, NCI, Frederick, Maryland
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Cancer Innovation Laboratory, NCI, Frederick, Maryland
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7
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Nussinov R, Zhang M, Maloney R, Liu Y, Tsai CJ, Jang H. Allostery: Allosteric Cancer Drivers and Innovative Allosteric Drugs. J Mol Biol 2022; 434:167569. [PMID: 35378118 PMCID: PMC9398924 DOI: 10.1016/j.jmb.2022.167569] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 03/11/2022] [Accepted: 03/25/2022] [Indexed: 01/12/2023]
Abstract
Here, we discuss the principles of allosteric activating mutations, propagation downstream of the signals that they prompt, and allosteric drugs, with examples from the Ras signaling network. We focus on Abl kinase where mutations shift the landscape toward the active, imatinib binding-incompetent conformation, likely resulting in the high affinity ATP outcompeting drug binding. Recent pharmacological innovation extends to allosteric inhibitor (GNF-5)-linked PROTAC, targeting Bcr-Abl1 myristoylation site, and broadly, allosteric heterobifunctional degraders that destroy targets, rather than inhibiting them. Designed chemical linkers in bifunctional degraders can connect the allosteric ligand that binds the target protein and the E3 ubiquitin ligase warhead anchor. The physical properties and favored conformational state of the engineered linker can precisely coordinate the distance and orientation between the target and the recruited E3. Allosteric PROTACs, noncompetitive molecular glues, and bitopic ligands, with covalent links of allosteric ligands and orthosteric warheads, increase the effective local concentration of productively oriented and placed ligands. Through covalent chemical or peptide linkers, allosteric drugs can collaborate with competitive drugs, degrader anchors, or other molecules of choice, driving innovative drug discovery.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Ryan Maloney
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Yonglan Liu
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Chung-Jung Tsai
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
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Li M, Wang Y, Fan J, Zhuang H, Liu Y, Ji D, Lu S. Mechanistic Insights into the Long-range Allosteric Regulation of KRAS Via Neurofibromatosis Type 1 (NF1) Scaffold Upon SPRED1 Loading. J Mol Biol 2022; 434:167730. [PMID: 35872068 DOI: 10.1016/j.jmb.2022.167730] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Revised: 06/22/2022] [Accepted: 07/08/2022] [Indexed: 01/17/2023]
Abstract
Allosteric regulation is the most direct and efficient way of regulating protein function, wherein proteins transmit the perturbations at one site to another distinct functional site. Deciphering the mechanism of allosteric regulation is of vital importance for the comprehension of both physiological and pathological events in vivo as well as the rational allosteric drug design. However, it remains challenging to elucidate dominant allosteric signal transduction pathways, especially for large and multi-component protein machineries where long-range allosteric regulation exits. One of the quintessential examples having long-range allosteric regulation is the ternary complex, SPRED1-RAS-neurofibromin type 1 (NF1, a RAS GTPase-activating protein), in which SPRED1 facilitates RAS-GTP hydrolysis by interacting with NF1 at a distal, allosteric site from the RAS binding site. To address the underlying mechanism, we performed extensive Gaussian accelerated molecular dynamics simulations and Markov state model analysis of KRAS-NF1 complex in the presence and absence of SPRED1. Our findings suggested that SPRED1 loading allosterically enhanced KRAS-NF1 binding, but hindered conformational transformation of the NF1 catalytic center for RAS hydrolysis. Moreover, we unveiled the possible allosteric pathways upon SPRED1 binding through difference contact network analysis. This study not only provided an in-depth mechanistic insight into the allosteric regulation of KRAS by SPRED1, but also shed light on the investigation of long-range allosteric regulation among complex macromolecular systems.
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Affiliation(s)
- Minyu Li
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Yuanhao Wang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Jigang Fan
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Haiming Zhuang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Yaqin Liu
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Dong Ji
- Department of Anesthesiology, Changhai Hospital, Navy Medical University, Shanghai 200433, China.
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China; Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China.
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9
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Ilter M, Kasmer R, Jalalypour F, Atilgan C, Topcu O, Karakas N, Sensoy O. Inhibition of mutant RAS-RAF interaction by mimicking structural and dynamic properties of phosphorylated RAS. eLife 2022; 11:79747. [PMID: 36458814 PMCID: PMC9762712 DOI: 10.7554/elife.79747] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Accepted: 11/30/2022] [Indexed: 12/03/2022] Open
Abstract
Undruggability of RAS proteins has necessitated alternative strategies for the development of effective inhibitors. In this respect, phosphorylation has recently come into prominence as this reversible post-translational modification attenuates sensitivity of RAS towards RAF. As such, in this study, we set out to unveil the impact of phosphorylation on dynamics of HRASWT and aim to invoke similar behavior in HRASG12D mutant by means of small therapeutic molecules. To this end, we performed molecular dynamics (MD) simulations using phosphorylated HRAS and showed that phosphorylation of Y32 distorted Switch I, hence the RAS/RAF interface. Consequently, we targeted Switch I in HRASG12D by means of approved therapeutic molecules and showed that the ligands enabled detachment of Switch I from the nucleotide-binding pocket. Moreover, we demonstrated that displacement of Switch I from the nucleotide-binding pocket was energetically more favorable in the presence of the ligand. Importantly, we verified computational findings in vitro where HRASG12D/RAF interaction was prevented by the ligand in HEK293T cells that expressed HRASG12D mutant protein. Therefore, these findings suggest that targeting Switch I, hence making Y32 accessible might open up new avenues in future drug discovery strategies that target mutant RAS proteins.
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Affiliation(s)
- Metehan Ilter
- Graduate School of Engineering and Natural Sciences, Istanbul Medipol UniversityIstanbulTurkey
| | - Ramazan Kasmer
- Medical Biology and Genetics Program, Graduate School for Health Sciences, Istanbul Medipol UniversityIstanbulTurkey,Cancer Research Center, Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol UniversityIstanbulTurkey
| | - Farzaneh Jalalypour
- Faculty of Engineering and Natural Sciences, Sabanci UniversityIstanbulTurkey
| | - Canan Atilgan
- Faculty of Engineering and Natural Sciences, Sabanci UniversityIstanbulTurkey
| | - Ozan Topcu
- Medical Biology and Genetics Program, Graduate School for Health Sciences, Istanbul Medipol UniversityIstanbulTurkey
| | - Nihal Karakas
- Medical Biology and Genetics Program, Graduate School for Health Sciences, Istanbul Medipol UniversityIstanbulTurkey,Department of Medical Biology, International School of Medicine, Istanbul Medipol UniversityIstanbulTurkey
| | - Ozge Sensoy
- Department of Computer Engineering, School of Engineering and Natural Sciences, Istanbul Medipol UniversityIstanbulTurkey,Regenerative and Restorative Medicine Research Center (REMER), Institute for Health Sciences and Technologies (SABITA), Istanbul Medipol UniversityIstanbulTurkey
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10
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Saijo-Hamano Y, Sherif AA, Pradipta A, Sasai M, Sakai N, Sakihama Y, Yamamoto M, Standley DM, Nitta R. Structural basis of membrane recognition of Toxoplasma gondii vacuole by Irgb6. Life Sci Alliance 2021; 5:5/1/e202101149. [PMID: 34753804 PMCID: PMC8605323 DOI: 10.26508/lsa.202101149] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 10/15/2021] [Accepted: 10/18/2021] [Indexed: 11/24/2022] Open
Abstract
Upon Toxoplasma gondii infection, Irgb6 is recruited to the parasitophorous vacuole membrane (PVM) where Irgb6 disrupts it. We solved the atomic structures of Irgb6 in two distinct nucleotide states, revealing a unique PVM-binding interface sensitive to GTPase cycling. The p47 immunity-related GTPase (IRG) Irgb6 plays a pioneering role in host defense against Toxoplasma gondii infection. Irgb6 is recruited to the parasitophorous vacuole membrane (PVM) formed by T. gondii and disrupts it. Despite the importance of this process, the molecular mechanisms accounting for PVM recognition by Irgb6 remain elusive because of lack of structural information on Irgb6. Here we report the crystal structures of mouse Irgb6 in the GTP-bound and nucleotide-free forms. Irgb6 exhibits a similar overall architecture to other IRGs in which GTP binding induces conformational changes in both the dimerization interface and the membrane-binding interface. The membrane-binding interface of Irgb6 assumes a unique conformation, composed of N- and C-terminal helical regions forming a phospholipid binding site. In silico docking of phospholipids further revealed membrane-binding residues that were validated through mutagenesis and cell-based assays. Collectively, these data demonstrate a novel structural basis for Irgb6 to recognize T. gondii PVM in a manner distinct from other IRGs.
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Affiliation(s)
- Yumiko Saijo-Hamano
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Aalaa Alrahman Sherif
- Depertment of Genome Informatics, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Ariel Pradipta
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,Laboratory of Immunoparasitology, World Premier International Immunology Frontier Research Center, Osaka University, Osaka, Japan
| | - Miwa Sasai
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,Laboratory of Immunoparasitology, World Premier International Immunology Frontier Research Center, Osaka University, Osaka, Japan.,Division of Microbiology and Immunology, Center for Infectious Disease Education and Research, Osaka University, Osaka, Japan
| | | | - Yoshiaki Sakihama
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Masahiro Yamamoto
- Department of Immunoparasitology, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan.,Laboratory of Immunoparasitology, World Premier International Immunology Frontier Research Center, Osaka University, Osaka, Japan.,Division of Microbiology and Immunology, Center for Infectious Disease Education and Research, Osaka University, Osaka, Japan
| | - Daron M Standley
- Depertment of Genome Informatics, Research Institute for Microbial Diseases, Osaka University, Osaka, Japan
| | - Ryo Nitta
- Division of Structural Medicine and Anatomy, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe, Japan
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Qiu Y, Wang Y, Chai Z, Ni D, Li X, Pu J, Chen J, Zhang J, Lu S, Lv C, Ji M. Targeting RAS phosphorylation in cancer therapy: Mechanisms and modulators. Acta Pharm Sin B 2021; 11:3433-3446. [PMID: 34900528 PMCID: PMC8642438 DOI: 10.1016/j.apsb.2021.02.014] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/26/2021] [Accepted: 02/16/2021] [Indexed: 12/17/2022] Open
Abstract
RAS, a member of the small GTPase family, functions as a binary switch by shifting between inactive GDP-loaded and active GTP-loaded state. RAS gain-of-function mutations are one of the leading causes in human oncogenesis, accounting for ∼19% of the global cancer burden. As a well-recognized target in malignancy, RAS has been intensively studied in the past decades. Despite the sustained efforts, many failures occurred in the earlier exploration and resulted in an ‘undruggable’ feature of RAS proteins. Phosphorylation at several residues has been recently determined as regulators for wild-type and mutated RAS proteins. Therefore, the development of RAS inhibitors directly targeting the RAS mutants or towards upstream regulatory kinases supplies a novel direction for tackling the anti-RAS difficulties. A better understanding of RAS phosphorylation can contribute to future therapeutic strategies. In this review, we comprehensively summarized the current advances in RAS phosphorylation and provided mechanistic insights into the signaling transduction of associated pathways. Importantly, the preclinical and clinical success in developing anti-RAS drugs targeting the upstream kinases and potential directions of harnessing allostery to target RAS phosphorylation sites were also discussed.
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Key Words
- ABL, Abelson
- APC, adenomatous polyposis coli
- Allostery
- CK1, casein kinase 1
- CML, chronic myeloid leukemia
- ER, endoplasmic reticulum
- GAPs, GTPase-activating proteins
- GEFs, guanine nucleotide exchange-factors
- GSK3, glycogen synthase kinase 3
- HVR, hypervariable region
- IP3R, inositol trisphosphate receptors
- LRP6, lipoprotein-receptor-related protein 6
- OMM, outer mitochondrial membrane
- PI3K, phosphatidylinositol 3-kinase
- PKC, protein kinase C
- PPIs, protein−protein interactions
- Phosphorylation
- Protein kinases
- RAS
- RIN1, RAB-interacting protein 1
- SHP2, SRC homology 2 domain containing phosphatase 2
- SOS, Son of Sevenless
- STK19, serine/threonine-protein kinase 19
- TKIs, tyrosine kinase inhibitors
- Undruggable
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Affiliation(s)
- Yuran Qiu
- Department of Urology, Changzheng Hospital, Naval Military Medical University, Shanghai 200003, China
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Yuanhao Wang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Zongtao Chai
- Department of Hepatic Surgery VI, Eastern Hepatobiliary Surgery Hospital, Second Military Medical University, Shanghai 200438, China
| | - Duan Ni
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Xinyi Li
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Jun Pu
- Department of Cardiology, Renji Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200120, China
| | - Jie Chen
- Department of Urology, Changzheng Hospital, Naval Military Medical University, Shanghai 200003, China
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
- Corresponding authors.
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
- Corresponding authors.
| | - Chuan Lv
- Department of Plastic Surgery, Changhai Hospital, Naval Military Medical University, Shanghai 200438, China
- Corresponding authors.
| | - Mingfei Ji
- Department of Urology, Changzheng Hospital, Naval Military Medical University, Shanghai 200003, China
- Corresponding authors.
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12
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Paleskava A, Kaiumov MY, Kirillov SV, Konevega AL. Peculiarities in Activation of Hydrolytic Activity of Elongation Factors. BIOCHEMISTRY (MOSCOW) 2021; 85:1422-1433. [PMID: 33280582 DOI: 10.1134/s0006297920110103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Translational GTPases (trGTPases) belong to the family of G proteins and play key roles at all stages of protein biosynthesis on the ribosome. Unidirectional and cyclic functioning of G proteins is ensured by their ability to switch between the active and inactive states due to GTP hydrolysis accelerated by the auxiliary GTPase-activating proteins. Although trGTPases interact with the ribosomes in different conformational states, they bind to the same conserved region, which, unlike in classical GTPase-activating proteins, is represented by ribosomal RNA. The resulting catalytic sites have almost identical structure in all elongation factors suggesting a common mechanism of GTP hydrolysis. However, fine details of the activated state formation and significantly different rates of GTP hydrolysis indicate the existence of distinctive features upon GTP hydrolysis catalyzed by the different factors. Here, we present a contemporary view on the mechanism of GTPase activation and GTP hydrolysis by the elongation factors EF-Tu, EF-G, and SelB based on the analysis of structural, biochemical, and bioinformatics data.
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Affiliation(s)
- A Paleskava
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of NRC "Kurchatov Institute", Gatchina, Leningrad Region, 188300, Russia
| | - M Yu Kaiumov
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of NRC "Kurchatov Institute", Gatchina, Leningrad Region, 188300, Russia
| | - S V Kirillov
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of NRC "Kurchatov Institute", Gatchina, Leningrad Region, 188300, Russia
| | - A L Konevega
- Petersburg Nuclear Physics Institute named by B.P. Konstantinov of NRC "Kurchatov Institute", Gatchina, Leningrad Region, 188300, Russia.
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13
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Regulation of the Small GTPase Ras and Its Relevance to Human Disease. METHODS IN MOLECULAR BIOLOGY (CLIFTON, N.J.) 2021; 2262:19-43. [PMID: 33977469 DOI: 10.1007/978-1-0716-1190-6_2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Ras research has experienced a considerable boost in recent years, not least prompted by the Ras initiative launched by the NCI in 2013 ( https://www.cancer.gov/research/key-initiatives/ras ), accompanied and conditioned by a strongly reinvigorated determination within the Ras community to develop therapeutics attacking directly the Ras oncoproteins. As a member of the small G-protein superfamily, function and transforming activity of Ras all revolve about its GDP/GTP loading status. For one thing, the extent of GTP loading will determine the proportion of active Ras in the cell, with implications for intensity and quality of downstream signaling. But also the rate of nucleotide exchange, i.e., the Ras-GDP/GTP cycling rate, can have a major impact on Ras function, as illustrated perhaps most impressively by newly discovered fast-cycling oncogenic mutants of the Ras-related GTPase Rac1. Thus, while the last years have witnessed memorable new findings and technical developments in the Ras field, leading to an improved insight into many aspects of Ras biology, they have not jolted at the basics, but rather deepened our view of the fundamental regulatory principles of Ras activity control. In this brief review, we revisit the role and mechanisms of Ras nucleotide loading and its implications for cancer in the light of recent findings.
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14
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Nussinov R, Jang H, Gursoy A, Keskin O, Gaponenko V. Inhibition of Nonfunctional Ras. Cell Chem Biol 2021; 28:121-133. [PMID: 33440168 PMCID: PMC7897307 DOI: 10.1016/j.chembiol.2020.12.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 10/28/2020] [Accepted: 12/21/2020] [Indexed: 02/07/2023]
Abstract
Intuitively, functional states should be targeted; not nonfunctional ones. So why could drugging the inactive K-Ras4BG12Cwork-but drugging the inactive kinase will likely not? The reason is the distinct oncogenic mechanisms. Kinase driver mutations work by stabilizing the active state and/or destabilizing the inactive state. Either way, oncogenic kinases are mostly in the active state. Ras driver mutations work by quelling its deactivation mechanisms, GTP hydrolysis, and nucleotide exchange. Covalent inhibitors that bind to the inactive GDP-bound K-Ras4BG12C conformation can thus work. By contrast, in kinases, allosteric inhibitors work by altering the active-site conformation to favor orthosteric drugs. From the translational standpoint this distinction is vital: it expedites effective pharmaceutical development and extends the drug classification based on the mechanism of action. Collectively, here we postulate that drug action relates to blocking the mechanism of activation, not to whether the protein is in the active or inactive state.
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Affiliation(s)
- Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA; Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel.
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, MD 21702, USA
| | - Attila Gursoy
- Department of Computer Engineering, Koc University, Istanbul 34450, Turkey
| | - Ozlem Keskin
- Department of Chemical and Biological Engineering, Koc University, Istanbul 34450, Turkey
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, IL 60607, USA.
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15
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Wang Y, Ji D, Lei C, Chen Y, Qiu Y, Li X, Li M, Ni D, Pu J, Zhang J, Fu Q, Liu Y, Lu S. Mechanistic insights into the effect of phosphorylation on Ras conformational dynamics and its interactions with cell signaling proteins. Comput Struct Biotechnol J 2021; 19:1184-1199. [PMID: 33680360 PMCID: PMC7902900 DOI: 10.1016/j.csbj.2021.01.044] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/29/2021] [Accepted: 01/30/2021] [Indexed: 02/07/2023] Open
Abstract
Ras undergoes interconversion between the active GTP-bound state and the inactive GDP-bound state. This GTPase cycle, which controls the activities of Ras, is accelerated by Ras GTPase-activating proteins (GAPs) and guanine nucleotide exchange factors (SOS). Oncogenic Ras mutations could affect the GTPase cycle and impair Ras functions. Additionally, Src-induced K-Ras Y32/64 dual phosphorylation has been reported to disrupt GTPase cycle and hinder Ras downstream signaling. However, the underlying mechanisms remain unclear. To address this, we performed molecular dynamics simulations (~30 μs in total) on unphosphorylated and phosphorylated K-Ras4B in GTP- and GDP-bound states, and on their complexes with GTPase cycle regulators (GAP and SOS) and the effector protein Raf. We found that K-Ras4B dual phosphorylation mainly alters the conformation at the nucleotide binding site and creates disorder at the catalytic site, resulting in the enlargement of GDP binding pocket and the retard of Ras-GTP intrinsic hydrolysis. We observed phosphorylation-induced shift in the distribution of Ras-GTP inactive-active sub-states and recognized potential druggable pockets in the phosphorylated Ras-GTP. Moreover, decreased catalytic competence or signal delivery abilities due to reduced binding affinities and/or distorted catalytic conformations of GAP, SOS and Raf were observed. In addition, the allosteric pathway from Ras/Raf interface to the distal Raf L4 loop was compromised by Ras phosphorylation. These results reveal the mechanisms by which phosphorylation influences the intrinsic or GAP/SOS catalyzed transformations between GTP- and GDP-bound states of Ras and its signal transduction to Raf. Our findings project Ras phosphorylation as a target for cancer drug discovery.
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Affiliation(s)
- Yuanhao Wang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Dong Ji
- Department of Anesthesiology, Changhai Hospital, The Second Military Medical University, Shanghai 200433, China
| | - Chaoyu Lei
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Yingfei Chen
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Yuran Qiu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Xinyi Li
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Mingyu Li
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Duan Ni
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
- The Charles Perkins Centre, University of Sydney, Sydney, NSW 2006, Australia
| | - Jun Pu
- Department of Cardiology, Renji Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200120, China
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
- Medicinal Chemistry and Bioinformatics Centre, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Qiang Fu
- Department of Orthopedics, Shanghai General Hospital, Shanghai Jiao Tong University, School of Medicine, Shanghai 200080, China
| | - Yaqin Liu
- Medicinal Chemistry and Bioinformatics Centre, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
- Medicinal Chemistry and Bioinformatics Centre, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
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16
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Identification of an individual with a SYGNAP1 pathogenic mutation in India. Mol Biol Rep 2020; 47:9225-9234. [PMID: 33090308 DOI: 10.1007/s11033-020-05915-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Accepted: 10/10/2020] [Indexed: 10/23/2022]
Abstract
Exome sequencing is a prominent tool to identify novel and deleterious mutations which could be non-sense, frameshift, and canonical splice-site mutations in a specific gene. De novo mutations in SYNGAP1, which codes for synaptic RAS-GTPase activating the protein, causes Intellectual disability (ID) and Autism Spectrum Disorder (ASD). SYNGAP1 related ASD/ID is one of the rare diseases that are detrimental to the healthy neuronal developmental and disrupts the global development of a child. We report the first SYNGAP1 heterozygous patient from Indian cohort. We report a case of a child of 2-year old with global developmental delay, microcephaly subtle dysmorphism, absence seizures, disrupted sleep, delay in learning a language, and eating problems. Upon further validation, the child has a few traits of ASD. Here, based on focused exome sequencing, we report a de novo heterozygous mutation in SYNGAP1 exon 11 with c. 1861 C > T (p.arg621ter). Currently, the child is on Atorvastatin, a RAS inhibitor, already available in the market for the treatment of hypercholesterolemia and has shown considerable improvement in global behaviour and cognitive development. The long-term follow up of the child's development would contribute to the already existing knowledge of the developmental trajectory in individuals with SYNGAP1 heterozygous mutation. In this report, we discuss the finding of a novel mutation in one of the genes, SYNGAP1, implicated in ASD/ID. Besides, we discuss the current treatment prescribed to the patient and the progress of global developmental of the child.
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17
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Sasaki S, Izumi H, Morimoto Y, Sakurai K, Mochizuki S. Induction of potent cell growth inhibition by schizophyllan/K-ras antisense complex in combination with gemcitabine. Bioorg Med Chem 2020; 28:115668. [PMID: 32828430 DOI: 10.1016/j.bmc.2020.115668] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Revised: 07/20/2020] [Accepted: 07/24/2020] [Indexed: 02/07/2023]
Abstract
Antisense oligonucleotides (AS-ODNs) specifically hybridize with target mRNAs, resulting in interference with the splicing mechanism or the regulation of protein translation. In our previous reports, we demonstrated that β-glucan schizophyllan (SPG) can form a complex with AS-ODNs attached with oligo deoxyadenosine dA40 (AS-ODN-dA40/SPG), and that this complex can be recognized by β-glucan receptor Dectin-1 on antigen presenting cells and lung cancer cells. In many types of cancer cell, activating K-ras mutations related to malignancy are frequently observed. In this study, we first designed 78 AS-ODNs for K-ras to optimize the sequence for highly efficient gene suppression. The selected AS-ODN (K-AS07) having dA40 made a complex with SPG. The resultant complex (K-AS07-dA40/SPG) showed an effect of silencing the ras gene in the cells (PC9: human adenocarcinoma differentiated from lung tissue) expressing Dectin-1, leading to the suppression of cell growth. Furthermore, the cytotoxic effect was enhanced when used in combination with the anticancer drug gemcitabine. Gemcitabine, a derivative of cytidine, was shown to interact with dA40 in a sequence-dependent manner. This interaction did not appear to be so strong, with the gemcitabine being released from the complex after internalization into the cells. SPG and the dA40 part of K-AS07-dA40 play roles in carriers for K-AS07 and gemcitabine, respectively, resulting in a strong cytotoxic effect. This combination effect is a novel feature of the AS-ODN-dA40/SPG complexes. These results could facilitate the clinical application of these complexes for cancer treatment.
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Affiliation(s)
- Shogo Sasaki
- Department of Chemistry and Biochemistry, The University of Kitakyushu, 1-1, Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0135, Japan
| | - Hiroto Izumi
- University of Occupational and Environmental Health, 1-1 Isegaoka, Yahatanishi-ku, Kitakyushu, Fukuoka 807-8555, Japan
| | - Yasuo Morimoto
- University of Occupational and Environmental Health, 1-1 Isegaoka, Yahatanishi-ku, Kitakyushu, Fukuoka 807-8555, Japan
| | - Kazuo Sakurai
- Department of Chemistry and Biochemistry, The University of Kitakyushu, 1-1, Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0135, Japan
| | - Shinichi Mochizuki
- Department of Chemistry and Biochemistry, The University of Kitakyushu, 1-1, Hibikino, Wakamatsu-ku, Kitakyushu, Fukuoka 808-0135, Japan.
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18
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Liu Z, Wang M, Wang H, Fang L, Gou S. Targeting RAS-RAF pathway significantly improves antitumor activity of Rigosertib-derived platinum(IV) complexes and overcomes cisplatin resistance. Eur J Med Chem 2020; 194:112269. [PMID: 32248002 DOI: 10.1016/j.ejmech.2020.112269] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 03/22/2020] [Accepted: 03/22/2020] [Indexed: 02/07/2023]
Abstract
RAS-RAF pathway presents a valuable target for the cancer treatment due to its important roles in the regulation of tumor proliferation, apoptosis and the obtained resistance. To explore such target a RAS/CRAF interference agent, was therefore conjugated with Pt(IV) prodrugs via ester bond, resulting in total eleven multifunctional Pt(IV) complexes. The complexes could target genomic DNA and disrupt the signaling transduction from RAS protein to CRAF so that block the mitogen-activated protein kinase (MAPK) signaling pathway. Experiments in vitro indicated that all of the Pt(IV) complexes showed potent anti-tumor activity with IC50 values ranged from 8 nM to 22.55 μM, which were significantly improved as compared with cisplatin (CDDP) whose IC50 values ranged from 5.45 μM to 9.05 μM. Among them, 26 exerted the best anti-tumor activity in vitro, which not only exhibited excellent cytotoxicity against normal tumor cells, but also against CDDP-resistance cell lines (e.g. A549/CDDP and SKOV-3/CDDP). Importantly, 26 only showed little effect on normal cell lines such as HUEVC and LO2. Besides, the following biological mechanisms studies demonstrated that 26 could efficiently enter. A549 cells, significantly arrest cell cycle at G2/M phase, disrupt the signaling pathway and trigger endogenous caspase apoptosis pathway. Furthermore, results of a xenograft subcutaneous model of A549 tumor showed that 26 could effectively decrease tumor growth rates without causing loss of bodyweight.
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Affiliation(s)
- Zhikun Liu
- Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing, 211189, China; Pharmaceutical Research Center, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China
| | - Meng Wang
- State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences of Guangxi Normal University, Guilin, 541004, China
| | - Hengshan Wang
- State Key Laboratory for the Chemistry and Molecular Engineering of Medicinal Resources, School of Chemistry and Pharmaceutical Sciences of Guangxi Normal University, Guilin, 541004, China
| | - Lei Fang
- Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing, 211189, China; Pharmaceutical Research Center, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China.
| | - Shaohua Gou
- Jiangsu Province Hi-Tech Key Laboratory for Biomedical Research, Southeast University, Nanjing, 211189, China; Pharmaceutical Research Center, School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, China.
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19
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Ilter M, Sensoy O. Catalytically Competent Non-transforming H-RAS G12P Mutant Provides Insight into Molecular Switch Function and GAP-independent GTPase Activity of RAS. Sci Rep 2019; 9:10967. [PMID: 31358828 PMCID: PMC6662853 DOI: 10.1038/s41598-019-47481-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2019] [Accepted: 07/15/2019] [Indexed: 01/06/2023] Open
Abstract
RAS mutants have been extensively studied as they are associated with development of cancer; however, H-RASG12P mutant has remained untouched since it does not lead to transformation in the cell. To the best of our knowledge, this is the first study where structural/dynamical properties of H-RASG12P have been investigated -in comparison to H-RASWT, H-RASG12D, RAF-RBD-bound and GAP-bound H-RASWT- using molecular dynamics simulations (total of 9 μs). We observed remarkable differences in dynamics of Y32. Specifically, it is located far from the nucleotide binding pocket in the catalytically-active GAP-bound H-RASWT, whereas it makes close interaction with the nucleotide in signaling-active systems (H-RASG12D, KRAS4BG12D, RAF-RBD-bound H-RASWT) and H-RASWT. The accessibility of Y32 in wild type protein is achieved upon GAP binding. Interestingly; however, it is intrinsically accessible in H-RASG12P. Considering the fact that incomplete opening of Y32 is associated with cancer, we propose that Y32 can be targeted by means of small therapeutics that can displace it from the nucleotide binding site, thus introducing intrinsic GTPase activity to RAS mutants, which cannot bind to GAP. Therefore, mimicking properties of H-RASG12P in RAS-centered drug discovery studies has the potential of improving success rates since it acts as a molecular switch per se.
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Affiliation(s)
- Metehan Ilter
- Istanbul Medipol University, The School of Engineering and Natural Sciences, Department of Biomedical Engineering, Istanbul, 34810, Turkey
| | - Ozge Sensoy
- Istanbul Medipol University, The School of Engineering and Natural Sciences, Department of Computer Engineering, Istanbul, 34810, Turkey.
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20
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Zhang H, Nielsen AL, Strømgaard K. Recent achievements in developing selective Gqinhibitors. Med Res Rev 2019; 40:135-157. [DOI: 10.1002/med.21598] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 04/09/2019] [Accepted: 04/26/2019] [Indexed: 02/06/2023]
Affiliation(s)
- Hang Zhang
- Key Laboratory of Advanced Drug Preparation Technologies, Ministry of Education, Co‐innovation Center of Henan Province for New Drug R&D and Preclinical Safety, and School of Pharmaceutical SciencesZhengzhou UniversityZhengzhou Henan China
| | - Alexander L. Nielsen
- Department of Drug Design and Pharmacology, Center for BiopharmaceuticalsUniversity of CopenhagenCopenhagen Denmark
| | - Kristian Strømgaard
- Department of Drug Design and Pharmacology, Center for BiopharmaceuticalsUniversity of CopenhagenCopenhagen Denmark
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21
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Ni D, Lu S, Zhang J. Emerging roles of allosteric modulators in the regulation of protein-protein interactions (PPIs): A new paradigm for PPI drug discovery. Med Res Rev 2019; 39:2314-2342. [PMID: 30957264 DOI: 10.1002/med.21585] [Citation(s) in RCA: 69] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Revised: 03/12/2019] [Accepted: 03/24/2019] [Indexed: 12/26/2022]
Abstract
Protein-protein interactions (PPIs) are closely implicated in various types of cellular activities and are thus pivotal to health and disease states. Given their fundamental roles in a wide range of biological processes, the modulation of PPIs has enormous potential in drug discovery. However, owing to the general properties of large, flat, and featureless interfaces of PPIs, previous attempts have demonstrated that the generation of therapeutic agents targeting PPI interfaces is challenging, rendering them almost "undruggable" for decades. To date, rapid progress in chemical and structural biology techniques has promoted the exploitation of allostery as a novel approach in drug discovery. By attaching to allosteric sites that are topologically and spatially distinct from PPI interfaces, allosteric modulators can achieve improved physiochemical properties. Thus, allosteric modulators may represent an alternative strategy to target intractable PPIs and have attracted intense pharmaceutical interest. In this review, we first briefly introduce the characteristics of PPIs and then present different approaches for investigating PPIs, as well as the latest methods for modulating PPIs. Importantly, we comprehensively review the recent progress in the development of allosteric modulators to inhibit or stabilize PPIs. Finally, we conclude with future perspectives on the discovery of allosteric PPI modulators, especially the application of computational methods to aid in allosteric PPI drug discovery.
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Affiliation(s)
- Duan Ni
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Clinical and Fundamental Research Center, Renji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Shaoyong Lu
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Clinical and Fundamental Research Center, Renji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China.,Medicinal Bioinformatics Center, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
| | - Jian Zhang
- Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Clinical and Fundamental Research Center, Renji Hospital, Shanghai Jiao-Tong University School of Medicine, Shanghai, China.,Medicinal Bioinformatics Center, Shanghai Jiao-Tong University School of Medicine, Shanghai, China.,Center for Single-Cell Omics, Shanghai Jiao-Tong University School of Medicine, Shanghai, China
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22
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WDR76 is a RAS binding protein that functions as a tumor suppressor via RAS degradation. Nat Commun 2019; 10:295. [PMID: 30655611 PMCID: PMC6336889 DOI: 10.1038/s41467-018-08230-6] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 12/19/2018] [Indexed: 12/15/2022] Open
Abstract
Stability regulation of RAS that can affect its activity, in addition to the oncogenic mutations, occurs in human cancer. However, the mechanisms for stability regulation of RAS involved in their activity and its roles in tumorigenesis are poorly explored. Here, we identify WD40-repeat protein 76 (WDR76) as one of the HRAS binding proteins using proteomic analyses of hepatocellular carcinomas (HCC) tissue. WDR76 plays a role as an E3 linker protein and mediates the polyubiquitination-dependent degradation of RAS. WDR76-mediated RAS destabilization results in the inhibition of proliferation, transformation, and invasion of liver cancer cells. WDR76-/- mice are more susceptible to diethylnitrosamine-induced liver carcinogenesis. Liver-specific WDR76 induction destabilizes Ras and markedly reduces tumorigenesis in HRasG12V mouse livers. The clinical relevance of RAS regulation by WDR76 is indicated by the inverse correlation of their expressions in HCC tissues. Our study demonstrates that WDR76 functions as a tumor suppressor via RAS degradation.
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Xu S, Long BN, Boris GH, Chen A, Ni S, Kennedy MA. Structural insight into the rearrangement of the switch I region in GTP-bound G12A K-Ras. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2017; 73:970-984. [PMID: 29199977 DOI: 10.1107/s2059798317015418] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 07/23/2017] [Accepted: 10/23/2017] [Indexed: 12/21/2022]
Abstract
K-Ras, a molecular switch that regulates cell growth, apoptosis and metabolism, is activated when it undergoes a conformation change upon binding GTP and is deactivated following the hydrolysis of GTP to GDP. Hydrolysis of GTP in water is accelerated by coordination to K-Ras, where GTP adopts a high-energy conformation approaching the transition state. The G12A mutation reduces intrinsic K-Ras GTP hydrolysis by an unexplained mechanism. Here, crystal structures of G12A K-Ras in complex with GDP, GTP, GTPγS and GppNHp, and of Q61A K-Ras in complex with GDP, are reported. In the G12A K-Ras-GTP complex, the switch I region undergoes a significant reorganization such that the Tyr32 side chain points towards the GTP-binding pocket and forms a hydrogen bond to the GTP γ-phosphate, effectively stabilizing GTP in its precatalytic state, increasing the activation energy required to reach the transition state and contributing to the reduced intrinsic GTPase activity of G12A K-Ras mutants.
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Affiliation(s)
- Shenyuan Xu
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Brian N Long
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Gabriel H Boris
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Anqi Chen
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Shuisong Ni
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
| | - Michael A Kennedy
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH 45056, USA
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Erwin N, Patra S, Dwivedi M, Weise K, Winter R. Influence of isoform-specific Ras lipidation motifs on protein partitioning and dynamics in model membrane systems of various complexity. Biol Chem 2017; 398:547-563. [PMID: 27977396 DOI: 10.1515/hsz-2016-0289] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2016] [Accepted: 12/07/2016] [Indexed: 12/17/2022]
Abstract
The partitioning of the lipidated signaling proteins N-Ras and K-Ras4B into various membrane systems, ranging from single-component fluid bilayers, binary fluid mixtures, heterogeneous raft model membranes up to complex native-like lipid mixtures (GPMVs) in the absence and presence of integral membrane proteins have been explored in the last decade in a combined chemical-biological and biophysical approach. These studies have revealed pronounced isoform-specific differences regarding the lateral distribution in membranes and formation of protein-rich membrane domains. In this context, we will also discuss the effects of lipid head group structure and charge density on the partitioning behavior of the lipoproteins. Moreover, the dynamic properties of N-Ras and K-Ras4B have been studied in different model membrane systems and native-like crowded milieus. Addition of crowding agents such as Ficoll and its monomeric unit, sucrose, gradually favors clustering of Ras proteins in forming small oligomers in the bulk; only at very high crowder concentrations association is disfavored.
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Affiliation(s)
- Nelli Erwin
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, Dortmund Technical University, Otto-Hahn-Strasse 4a, D-44227 Dortmund
| | - Satyajit Patra
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, Dortmund Technical University, Otto-Hahn-Strasse 4a, D-44227 Dortmund
| | - Mridula Dwivedi
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, Dortmund Technical University, Otto-Hahn-Strasse 4a, D-44227 Dortmund
| | - Katrin Weise
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, Dortmund Technical University, Otto-Hahn-Strasse 4a, D-44227 Dortmund
| | - Roland Winter
- Physical Chemistry I - Biophysical Chemistry, Faculty of Chemistry and Chemical Biology, Dortmund Technical University, Otto-Hahn-Strasse 4a, D-44227 Dortmund
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Kopra K, van Adrichem AJ, Salo-Ahen OMH, Peltonen J, Wennerberg K, Härmä H. High-Throughput Dual Screening Method for Ras Activities and Inhibitors. Anal Chem 2017; 89:4508-4516. [PMID: 28318223 DOI: 10.1021/acs.analchem.6b04904] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Ras GTPases act as "molecular switches", alternating between inactive GDP-bound and active GTP-bound conformation. Ras-oncogenes were discovered over three decades ago, but there are still no effective therapies for Ras-driven cancers. So far, drug discovery strategies have been unsuccessful, because of a lack of suitable screening methodologies and well-defined binding pockets on the Ras proteins. Here, we addressed the former by introducing a homogeneous quenching resonance energy transfer (QRET) technique-based screening strategy for Ras interfacial and competitive inhibitors. We demonstrate that using a unique GTP-specific antibody fragment to monitor GTPase cycling in the presence of a guanine nucleotide exchange factor (GEF) and a GTPase activating protein (GAP) is an efficient method for Ras inhibitor high-throughput screening. When compared to a conventional GEF-stimulated nucleotide exchange assay in a proof-of-concept screen, we identified an overlapping set of potential inhibitor compounds but also compounds found exclusively with the new GTP hydrolysis monitoring-based GTPase cycling assay.
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Affiliation(s)
- Kari Kopra
- Institute of Biomedicine, University of Turku , Kiinamyllynkatu 10 C, FI-20520 Turku, Finland
| | - Arjan J van Adrichem
- Institute for Molecular Medicine Finland, University of Helsinki , Tukholmankatu 8, FI-00290 Helsinki, Finland
| | - Outi M H Salo-Ahen
- Structural Bioinformatics Laboratory and Pharmaceutical Sciences Laboratory, Faculty of Science and Engineering, Biochemistry and Pharmacy, Åbo Akademi University , Tykistökatu 6A, FI-20520 Turku, Finland
| | - Juha Peltonen
- Institute of Biomedicine, University of Turku , Kiinamyllynkatu 10 C, FI-20520 Turku, Finland
| | - Krister Wennerberg
- Institute for Molecular Medicine Finland, University of Helsinki , Tukholmankatu 8, FI-00290 Helsinki, Finland
| | - Harri Härmä
- Institute of Biomedicine, University of Turku , Kiinamyllynkatu 10 C, FI-20520 Turku, Finland
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Mao H, Saha M, Reyes-Aldrete E, Sherman MB, Woodson M, Atz R, Grimes S, Jardine PJ, Morais MC. Structural and Molecular Basis for Coordination in a Viral DNA Packaging Motor. Cell Rep 2016; 14:2017-2029. [PMID: 26904950 DOI: 10.1016/j.celrep.2016.01.058] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/04/2016] [Accepted: 01/17/2016] [Indexed: 02/02/2023] Open
Abstract
Ring NTPases are a class of ubiquitous molecular motors involved in basic biological partitioning processes. dsDNA viruses encode ring ATPases that translocate their genomes to near-crystalline densities within pre-assembled viral capsids. Here, X-ray crystallography, cryoEM, and biochemical analyses of the dsDNA packaging motor in bacteriophage phi29 show how individual subunits are arranged in a pentameric ATPase ring and suggest how their activities are coordinated to translocate dsDNA. The resulting pseudo-atomic structure of the motor and accompanying functional analyses show how ATP is bound in the ATPase active site; identify two DNA contacts, including a potential DNA translocating loop; demonstrate that a trans-acting arginine finger is involved in coordinating hydrolysis around the ring; and suggest a functional coupling between the arginine finger and the DNA translocating loop. The ability to visualize the motor in action illuminates how the different motor components interact with each other and with their DNA substrate.
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Affiliation(s)
- Huzhang Mao
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Mitul Saha
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Emilio Reyes-Aldrete
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Michael B Sherman
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Michael Woodson
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Rockney Atz
- Department of Diagnostic and Biological Sciences, School of Dentistry, and Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Shelley Grimes
- Department of Diagnostic and Biological Sciences, School of Dentistry, and Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Paul J Jardine
- Department of Diagnostic and Biological Sciences, School of Dentistry, and Institute for Molecular Virology, University of Minnesota, Minneapolis, MN 55455, USA
| | - Marc C Morais
- Sealy Center for Structural Biology and Molecular Biophysics, Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, TX 77555, USA
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27
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Lu S, Jang H, Muratcioglu S, Gursoy A, Keskin O, Nussinov R, Zhang J. Ras Conformational Ensembles, Allostery, and Signaling. Chem Rev 2016; 116:6607-65. [PMID: 26815308 DOI: 10.1021/acs.chemrev.5b00542] [Citation(s) in RCA: 259] [Impact Index Per Article: 32.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ras proteins are classical members of small GTPases that function as molecular switches by alternating between inactive GDP-bound and active GTP-bound states. Ras activation is regulated by guanine nucleotide exchange factors that catalyze the exchange of GDP by GTP, and inactivation is terminated by GTPase-activating proteins that accelerate the intrinsic GTP hydrolysis rate by orders of magnitude. In this review, we focus on data that have accumulated over the past few years pertaining to the conformational ensembles and the allosteric regulation of Ras proteins and their interpretation from our conformational landscape standpoint. The Ras ensemble embodies all states, including the ligand-bound conformations, the activated (or inactivated) allosteric modulated states, post-translationally modified states, mutational states, transition states, and nonfunctional states serving as a reservoir for emerging functions. The ensemble is shifted by distinct mutational events, cofactors, post-translational modifications, and different membrane compositions. A better understanding of Ras biology can contribute to therapeutic strategies.
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Affiliation(s)
- Shaoyong Lu
- Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine , Shanghai, 200025, China.,Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute , Frederick, Maryland 21702, United States
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute , Frederick, Maryland 21702, United States
| | | | | | | | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute , Frederick, Maryland 21702, United States.,Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Sackler Institute of Molecular Medicine, Tel Aviv University , Tel Aviv 69978, Israel
| | - Jian Zhang
- Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine , Shanghai, 200025, China
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Lu S, Jang H, Zhang J, Nussinov R. Inhibitors of Ras-SOS Interactions. ChemMedChem 2015; 11:814-21. [PMID: 26630662 DOI: 10.1002/cmdc.201500481] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Indexed: 12/18/2022]
Abstract
Activating Ras mutations are found in about 30 % of human cancers. Ras activation is regulated by guanine nucleotide exchange factors, such as the son of sevenless (SOS), which form protein-protein interactions (PPIs) with Ras and catalyze the exchange of GDP by GTP. This is the rate-limiting step in Ras activation. However, Ras surfaces lack any evident suitable pockets where a molecule might bind tightly, rendering Ras proteins still 'undruggable' for over 30 years. Among the alternative approaches is the design of inhibitors that target the Ras-SOS PPI interface, a strategy that is gaining increasing recognition for treating Ras mutant cancers. Herein we focus on data that has accumulated over the past few years pertaining to the design of small-molecule modulators or peptide mimetics aimed at the interface of the Ras-SOS PPI. We emphasize, however, that even if such Ras-SOS therapeutics are potent, drug resistance may emerge. To counteract this development, we propose "pathway drug cocktails", that is, drug combinations aimed at parallel (or compensatory) pathways. A repertoire of classified cancer, cell/tissue, and pathway/protein combinations would be beneficial toward this goal.
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Affiliation(s)
- Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200025, China
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research Inc., Frederick National Laboratory, National Cancer Institute, Frederick, MD, 21702, USA
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200025, China.
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research Inc., Frederick National Laboratory, National Cancer Institute, Frederick, MD, 21702, USA. .,Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Sackler Institute of Molecular Medicine, Tel Aviv University, Tel Aviv, 69978, Israel.
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29
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Ricciuti B, Leonardi GC, Metro G, Grignani F, Paglialunga L, Bellezza G, Baglivo S, Mencaroni C, Baldi A, Zicari D, Crinò L. Targeting the KRAS variant for treatment of non-small cell lung cancer: potential therapeutic applications. Expert Rev Respir Med 2015; 10:53-68. [PMID: 26714748 DOI: 10.1586/17476348.2016.1115349] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Lung cancer is the leading cause of cancer deaths worldwide, with non-small cell lung cancer (NSCLC) accounting for 80% of all lung cancers. Kirsten rat sarcoma viral oncogene homolog (KRAS) is one of the deadliest cancer-related proteins and plays a pivotal role in the most aggressive and lethal human cancers, including lung adenocarcinoma where it represents one of the most frequently mutated oncogene. Although therapeutic progresses have made an impact over the last decade, median survival for patients with advanced lung cancer remains disappointing, with a 5-year worldwide survival rate of <15%. For more than 20 years it has been recognized that constitutively active signaling downstream of KRAS is a fundamental driver of lung tumorigenesis. However, years of pursuit have failed to yield a drug that can safely curb KRAS activity; up to now no approved therapies exist for KRAS-mutant NSCLC. The aim of this review is to discuss the current knowledge of KRAS-mutated NSCLC, touching upon KRAS clinical relevance as a prognostic and predictive biomarker, with an emphasis on novel therapeutic approaches for the treatment of KRAS-variant NSCLC.
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Affiliation(s)
- Biagio Ricciuti
- a Medical Oncology , Santa Maria della Misericordia Hospital, Azienda Ospedaliera di Perugia , Perugia , Italy
| | - Giulia Costanza Leonardi
- a Medical Oncology , Santa Maria della Misericordia Hospital, Azienda Ospedaliera di Perugia , Perugia , Italy
| | - Giulio Metro
- a Medical Oncology , Santa Maria della Misericordia Hospital, Azienda Ospedaliera di Perugia , Perugia , Italy
| | - Francesco Grignani
- b Department of Clinical and Experimental Medicine, Division of Pathology , University of Perugia , Perugia , Italy
| | - Luca Paglialunga
- a Medical Oncology , Santa Maria della Misericordia Hospital, Azienda Ospedaliera di Perugia , Perugia , Italy
| | - Guido Bellezza
- c Department of Experimental Medicine, Division of Pathology and Histology , University of Perugia , Perugia , Italy
| | - Sara Baglivo
- a Medical Oncology , Santa Maria della Misericordia Hospital, Azienda Ospedaliera di Perugia , Perugia , Italy
| | - Clelia Mencaroni
- a Medical Oncology , Santa Maria della Misericordia Hospital, Azienda Ospedaliera di Perugia , Perugia , Italy
| | - Alice Baldi
- a Medical Oncology , Santa Maria della Misericordia Hospital, Azienda Ospedaliera di Perugia , Perugia , Italy
| | - Daniela Zicari
- a Medical Oncology , Santa Maria della Misericordia Hospital, Azienda Ospedaliera di Perugia , Perugia , Italy
| | - Lucio Crinò
- a Medical Oncology , Santa Maria della Misericordia Hospital, Azienda Ospedaliera di Perugia , Perugia , Italy
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Abstract
Pancreatic ductal adenocarcinoma remains a clinical challenge. Thus far, enlightenment on the downstream activities of Kras, the tumor's unique metabolic needs, and how the stroma and immune system affect it have remained untranslated to the clinical practice. Given the numbers of diverse therapies in development and a growing knowledge about how to evaluate these systems preclinically and clinically, this is expected to change significantly and for the better over the next 5 years.
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Role of a ribosomal RNA phosphate oxygen during the EF-G-triggered GTP hydrolysis. Proc Natl Acad Sci U S A 2015; 112:E2561-8. [PMID: 25941362 DOI: 10.1073/pnas.1505231112] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Elongation factor-catalyzed GTP hydrolysis is a key reaction during the ribosomal elongation cycle. Recent crystal structures of G proteins, such as elongation factor G (EF-G) bound to the ribosome, as well as many biochemical studies, provide evidence that the direct interaction of translational GTPases (trGTPases) with the sarcin-ricin loop (SRL) of ribosomal RNA (rRNA) is pivotal for hydrolysis. However, the precise mechanism remains elusive and is intensively debated. Based on the close proximity of the phosphate oxygen of A2662 of the SRL to the supposedly catalytic histidine of EF-G (His87), we probed this interaction by an atomic mutagenesis approach. We individually replaced either of the two nonbridging phosphate oxygens at A2662 with a methyl group by the introduction of a methylphosphonate instead of the natural phosphate in fully functional, reconstituted bacterial ribosomes. Our major finding was that only one of the two resulting diastereomers, the SP methylphosphonate, was compatible with efficient GTPase activation on EF-G. The same trend was observed for a second trGTPase, namely EF4 (LepA). In addition, we provide evidence that the negative charge of the A2662 phosphate group must be retained for uncompromised activity in GTP hydrolysis. In summary, our data strongly corroborate that the nonbridging proSP phosphate oxygen at the A2662 of the SRL is critically involved in the activation of GTP hydrolysis. A mechanistic scenario is supported in which positioning of the catalytically active, protonated His87 through electrostatic interactions with the A2662 phosphate group and H-bond networks are key features of ribosome-triggered activation of trGTPases.
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Gong B, Liu WW, Nie WJ, Li DF, Xie ZJ, Liu C, Liu YH, Mei P, Li ZJ. MiR-21/RASA1 axis affects malignancy of colon cancer cells via RAS pathways. World J Gastroenterol 2015; 21:1488-97. [PMID: 25663768 PMCID: PMC4316091 DOI: 10.3748/wjg.v21.i5.1488] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2014] [Revised: 08/28/2014] [Accepted: 09/30/2014] [Indexed: 02/06/2023] Open
Abstract
AIM To determine how the oncogene miR-21 regulates the RAS signaling pathways and affects colon cancer cell behaviors. METHODS RAS p21 GTPase activating protein 1 (RASA1) protein expression in six colon cancer cell lines was assessed by Western blot. Colon cancer RKO cells were chosen for transfection because they are KRAS wild type colon cancer cells whose RASA1 expression is significantly decreased. RKO cells were transfected with vectors overexpressing or down-regulating either miR-21 or RASA1. Furthermore, a luciferase reporter assay was used to determine whether RASA1 is a gene target of miR-21. Then, changes in mRNA and protein levels of RASA1, RAS-GTP, and other components of the RAS signaling pathways were assessed in transfected RKO cells by real-time quantitative reverse transcription-polymerase chain reaction, Western blot and immunoprecipitation. Finally, cell proliferation, apoptosis, invasion, and tumor formation ability were assessed by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide dye assay, flow cytometry, transwell assay, and animal experiment, respectively. RESULTS RASA1 protein levels were significantly decreased in RKO cells compared with the other 5 colon cancer cell lines, and RASA1 was confirmed as a target gene of miR-21. Interestingly, RASA1 mRNA and protein levels in pre-miR-21-LV (up-regulation of miR-21) cells were lower than those in anti-miR-21-LV (down-regulation of miR-21) cells (P < 0.05). In addition, pre-miR-21-LV or siRASA1 (down-regulation of RASA1) cells showed higher cell proliferation, reduced apoptosis, increased expression of RAS-GTP, p-AKT, Raf-1, KRAS, and p-ERK1/2, and higher invasion and tumor formation ability, compared with control, anti-miR-21-LV or pcDNA3.1-RASA1 (up-regulation of RASA1) cells (P < 0.05). CONCLUSION RASA1 is a target gene of miR-21, which promotes malignant behaviors of RKO cells through regulation of RASA1 expression.
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A homogeneous quenching resonance energy transfer assay for the kinetic analysis of the GTPase nucleotide exchange reaction. Anal Bioanal Chem 2014; 406:4147-56. [PMID: 24760397 DOI: 10.1007/s00216-014-7795-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/04/2014] [Accepted: 03/26/2014] [Indexed: 01/09/2023]
Abstract
A quenching resonance energy transfer (QRET) assay for small GTPase nucleotide exchange kinetic monitoring is demonstrated using nanomolar protein concentrations. Small GTPases are central signaling proteins in all eukaryotic cells acting as a "molecular switches" that are active in the GTP-state and inactive in the GDP-state. GTP-loading is highly regulated by guanine nucleotide exchange factors (GEFs). In several diseases, most prominently cancer, this process in misregulated. The kinetics of the nucleotide exchange reaction reports on the enzymatic activity of the GEF reaction system and is, therefore, of special interest. We determined the nucleotide exchange kinetics using europium-labeled GTP (Eu-GTP) in the QRET assay for small GTPases. After GEF catalyzed GTP-loading of a GTPase, a high time-resolved luminescence signal was found to be associated with GTPase bound Eu-GTP, whereas the non-bound Eu-GTP fraction was quenched by soluble quencher. The association kinetics of the Eu-GTP was measured after GEF addition, whereas the dissociation kinetics could be determined after addition of unlabeled GTP. The resulting association and dissociation rates were in agreement with previously published values for H-Ras(Wt), H-Ras(Q61G), and K-Ras(Wt), respectively. The broader applicability of the QRET assay for small GTPases was demonstrated by determining the kinetics of the Ect2 catalyzed RhoA(Wt) GTP-loading. The QRET assay allows the use of nanomolar protein concentrations, as more than 3-fold signal-to-background ratio was achieved with 50 nM GTPase and GEF proteins. Thus, small GTPase exchange kinetics can be efficiently determined in a HTS compatible 384-well plate format.
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Durães C, Almeida GM, Seruca R, Oliveira C, Carneiro F. Biomarkers for gastric cancer: prognostic, predictive or targets of therapy? Virchows Arch 2014; 464:367-78. [DOI: 10.1007/s00428-013-1533-y] [Citation(s) in RCA: 124] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Revised: 11/12/2013] [Accepted: 12/23/2013] [Indexed: 12/12/2022]
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Abstract
Genomic variation is a trend observed in various human diseases including cancer. Genetic studies have set out to understand how and why these variations result in cancer, why some populations are pre-disposed to the disease, and also how genetics affect drug responses. The melanoma incidence has been increasing at an alarming rate worldwide. The burden posed by melanoma has made it a necessity to understand the fundamental signaling pathways involved in this deadly disease. Signaling cascades such as mitogen-activated protein kinase and PI3K/AKT have been shown to be crucial in the regulation of processes that are commonly dysregulated during cancer development such as aberrant proliferation, loss of cell cycle control, impaired apoptosis, and altered drug metabolism. Understanding how these and other oncogenic pathways are regulated has been integral in our challenge to develop potent anti-melanoma drugs. With advances in technology and especially in next generation sequencing, we have been able to explore melanoma genomes and exomes leading to the identification of previously unknown genes with functions in melanomagenesis such as GRIN2A and PREX2. The therapeutic potential of these novel candidate genes is actively being pursued with some presenting as druggable targets while others serve as indicators of therapeutic responses. In addition, the analysis of the mutational signatures of melanoma tumors continues to cement the causative role of UV exposure in melanoma pathogenesis. It has become distinctly clear that melanomas from sun-exposed skin areas have distinct mutational signatures including C to T transitions indicative of UV-induced damage. It is thus necessary to continue spreading awareness on how to decrease the risk factors of developing the disease while at the same time working for a cure. Given the large amount of information gained from these sequencing studies, it is likely that in the future, treatment of melanoma will follow a highly personalized route that takes into account the differential mutational signatures of each individual’s cancer.
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Affiliation(s)
- Janet Wangari-Talbot
- Susan Lehman Cullman Laboratory for Cancer Research, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey Piscataway, NJ, USA
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Nelson SA, Sanson AM, Park HO, Cooper JA. A novel role for the GTPase-activating protein Bud2 in the spindle position checkpoint. PLoS One 2012; 7:e36127. [PMID: 22558355 PMCID: PMC3338500 DOI: 10.1371/journal.pone.0036127] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2012] [Accepted: 03/30/2012] [Indexed: 12/21/2022] Open
Abstract
The spindle position checkpoint (SPC) ensures correct mitotic spindle position before allowing mitotic exit in the budding yeast Saccharomyces cerevisiae. In a candidate screen for checkpoint genes, we identified bud2Δ as deficient for the SPC. Bud2 is a GTPase activating protein (GAP), and the only known substrate of Bud2 was Rsr1/Bud1, a Ras-like GTPase and a central component of the bud-site-selection pathway. Mutants lacking Rsr1/Bud1 had no checkpoint defect, as did strains lacking and overexpressing Bud5, a guanine-nucleotide exchange factor (GEF) for Rsr1/Bud1. Thus, the checkpoint function of Bud2 is distinct from its role in bud site selection. The catalytic activity of the Bud2 GAP domain was required for the checkpoint, based on the failure of the known catalytic point mutant Bud2R682A to function in the checkpoint. Based on assays of heterozygous diploids, bud2R682A, was dominant for loss of checkpoint but recessive for bud-site-selection failure, further indicating a separation of function. Tem1 is a Ras-like protein and is the critical regulator of mitotic exit, sitting atop the mitotic exit network (MEN). Tem1 is a likely target for Bud2, supported by genetic analyses that exclude other Ras-like proteins.
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Affiliation(s)
- Scott A. Nelson
- Department of Cell Biology and Physiology, Washington University, Saint Louis, Missouri, United States of America
| | - Anthony M. Sanson
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - Hay-Oak Park
- Department of Molecular Genetics, The Ohio State University, Columbus, Ohio, United States of America
| | - John A. Cooper
- Department of Cell Biology and Physiology, Washington University, Saint Louis, Missouri, United States of America
- * E-mail:
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Prakash P, Sayyed-Ahmad A, Gorfe AA. The role of conserved waters in conformational transitions of Q61H K-ras. PLoS Comput Biol 2012; 8:e1002394. [PMID: 22359497 PMCID: PMC3280954 DOI: 10.1371/journal.pcbi.1002394] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Accepted: 01/04/2012] [Indexed: 12/30/2022] Open
Abstract
To investigate the stability and functional role of long-residence water molecules in the Q61H variant of the signaling protein K-ras, we analyzed all available Ras crystal structures and conformers derived from a series of independent explicit solvent molecular dynamics (MD) simulations totaling 1.76 µs. We show that the protein samples a different region of phase space in the presence and absence of several crystallographically conserved and buried water molecules. The dynamics of these waters is coupled with the local as well as the global motions of the protein, in contrast to less buried waters whose exchange with bulk is only loosely coupled with the motion of loops in their vicinity. Aided by two novel reaction coordinates involving the distance (d) between the Cα atoms of G60 at switch 2 and G10 at the P-loop and the N-Cα-C-O dihedral (ξ) of G60, we further show that three water molecules located in lobe1, at the interface between the lobes and at lobe2, are involved in the relative motion of residues at the two lobes of Q61H K-ras. Moreover, a d/ξ plot classifies the available Ras x-ray structures and MD-derived K-ras conformers into active GTP-, intermediate GTP-, inactive GDP-bound, and nucleotide-free conformational states. The population of these states and the transition between them is modulated by water-mediated correlated motions involving the functionally critical switch 2, P-loop and helix 3. These results suggest that water molecules act as allosteric ligands to induce a population shift among distinct switch 2 conformations that differ in effector recognition. K-ras belongs to the Ras family of G-proteins that regulate cell proliferation and development. To execute its function, K-ras adopts different conformational states when it is active and inactive. In addition to these two states, it samples many transient intermediate conformations as it makes the transition from one state to the other. Mutations that affect the population of these states can cause cancer or developmental disorder. Using simulation approaches, here we show that a number of water molecules buried within the structure of an oncogenic K-ras protein modulate the distribution of its conformational states. Moreover, a detailed analysis based on two novel structural parameters revealed the existence of long-range water-mediated interactions that facilitate a dynamic coupling between the two lobes of the protein. These findings pave the way for a dynamics-guided strategy to inhibit abnormal Ras signaling.
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Affiliation(s)
- Priyanka Prakash
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Abdallah Sayyed-Ahmad
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
| | - Alemayehu A. Gorfe
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- Center for Membrane Biology, University of Texas Health Science Center at Houston, Houston, Texas, United States of America
- * E-mail:
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38
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Abstract
We have used a mathematical model of the Ras signaling network to link observable biochemical properties with cellular levels of RasGTP. Although there is abundant data characterizing Ras biochemistry, attributing specific changes in biochemical properties to observed phenotypes has been hindered by the scope and complexity of Ras regulation. A mathematical model of the Ras signaling module, therefore, appeared to be of value for this problem. The model described the core architecture shared by pathways that signal through Ras. Mass-action kinetics and ordinary differential equations were used to describe network reactions. Needed parameters were largely available in the published literature and resulted in a model with good agreement to experimental data. Computational analysis of the model resulted in several unanticipated predictions and suggested experiments that subsequently validated some of these predictions.
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Morais MC. The dsDNA Packaging Motor in Bacteriophage ø29. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 726:511-47. [DOI: 10.1007/978-1-4614-0980-9_23] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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Rojas JM, Oliva JL, Santos E. Mammalian son of sevenless Guanine nucleotide exchange factors: old concepts and new perspectives. Genes Cancer 2011; 2:298-305. [PMID: 21779500 DOI: 10.1177/1947601911408078] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The Son of Sevenless (Sos) factors were originally discovered 2 decades ago as specialized Ras activators in signaling pathways controlling the process of R7 cell development in the eye of Drosophila melanogaster. The 2 known members of the mammalian Sos family (Sos1 and Sos2) code for ubiquitously expressed, highly homologous (69% overall) proteins involved in coupling signals originated by cell surface receptor tyrosine kinases (RTKs) to downstream, Ras-dependent mitogenic signaling pathways. Mechanistically, the Sos proteins function as enzymatic factors interacting with Ras proteins in response to upstream stimuli to promote guanine nucleotide exchange (GDP/GTP) and subsequent formation of the active Ras-GTP complex. In this review, we summarize current knowledge on structural, regulatory, and functional aspects of the Sos family, focusing on specific aspects of Sos biology such as structure-function relationship, crosstalk with different signaling pathways, and in vivo functional significance as deduced from phenotypic characterization of Sos knockout mice and human genetic syndromes caused by germline hSos1 mutations.
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Affiliation(s)
- José M Rojas
- Unidad de Biología Celular, Área de Biología Celular y del Desarrollo, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
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Wang JH, Newbury LJ, Knisely AS, Monia B, Hendry BM, Sharpe CC. Antisense knockdown of Kras inhibits fibrosis in a rat model of unilateral ureteric obstruction. THE AMERICAN JOURNAL OF PATHOLOGY 2011; 180:82-90. [PMID: 22074740 DOI: 10.1016/j.ajpath.2011.09.036] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 08/26/2011] [Accepted: 09/26/2011] [Indexed: 11/28/2022]
Abstract
Tubulointerstitial fibrosis is the hallmark of chronic kidney disease and is characterized by an increase in the number and activity of interstitial fibroblasts and by excessive matrix deposition. Ras is an intracellular signaling molecule involved in cell proliferation and differentiation. It has recently been implicated in the pathogenesis of renal fibrosis. Of the three different isoforms of Ras (Kirsten, Harvey, and Neural), we previously demonstrated that the Kirsten isoform is key in the control of renal fibroblast proliferation in vitro. In this study, we used gene therapy in the form of antisense oligonucleotides (ASOs) specifically to silence Kras (alias Ki-ras) expression in a rat model of renal fibrosis caused by unilateral ureteric obstruction. We demonstrate that renal Kras expression increases by 70% in this model compared with sham-operated animals and that treatment with ASOs can reduce total renal Kras by >90% to levels well below basal. This silencing is associated with a dramatic inhibition of interstitial fibrosis, a fivefold reduction in α-smooth muscle actin expression, and a 2.4-fold reduction in collagen I deposition. This inhibition was observed despite histologic evidence of marked interstitial inflammation. These findings demonstrate that silencing Kras expression can markedly inhibit renal fibrosis. This strategy should be considered as a new potential therapeutic avenue.
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Affiliation(s)
- Jia-Hui Wang
- Department of Renal Medicine, King's College Hospital, London, United Kingdom
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Abstract
INTRODUCTION Inhibitors targeting oncogenic kinases, especially receptor tyrosine kinases (RTKs), are being vigorously developed, and some have been demonstrated to be effective in clinical settings. The amplification of certain RTKs (ErbB2, c-Met and FGFR2) is associated with gastric cancer progression, but the only recently approved inhibitor is trastuzumab, ErbB2-targeting antibody. Other well-known oncogenic kinases (PI3K and RAF) are also activated in a small portion of gastric cancers. Drugs targeting these kinases are promising and should be approved in an appropriate and expeditious way. AREAS COVERED This article reviews novel inhibitors emerging in the field of advanced gastric cancer, based on basic research concerning altered oncogenes and the clinical trials of drugs targeting these oncogenes. EXPERT OPINION Promising inhibitors of gastric cancer may be found in not only new investigative agents but also agents currently being used against other malignancies. The appropriate design for clinical trials of molecularly targeted therapeutic agents is also important. Targeted therapies tailored to individual genomic profiles would provide a more personalized treatment for advanced gastric cancer.
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Affiliation(s)
- Yoshinari Asaoka
- The University of Tokyo, Graduate School of Medicine, Department of Gastroenterology, Japan.
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Overmeyer JH, Maltese WA. Death pathways triggered by activated Ras in cancer cells. Front Biosci (Landmark Ed) 2011; 16:1693-713. [PMID: 21196257 DOI: 10.2741/3814] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Ras GTPases are best known for their ability to serve as molecular switches regulating cell growth, differentiation and survival. Gene mutations that result in expression of constitutively active forms of Ras have been linked to oncogenesis in animal models and humans. However, over the past two decades, evidence has gradually accumulated to support a paradoxical role for Ras proteins in the initiation of cell death pathways. In this review we survey the literature pointing to the ability of activated Ras to promote cell death under conditions where cancer cells encounter apoptotic stimuli or Ras is ectopically expressed. In some of these cases Ras acts through known effectors and well defined apoptotic death pathways. However, in other cases it appears that Ras operates by triggering novel non-apoptotic death mechanisms that are just beginning to be characterized. Understanding these mechanisms and the factors that go into changing the nature of Ras signaling from pro-survival to pro-death could set the stage for development of novel therapeutic approaches aimed at manipulating pro-death Ras signaling pathways in cancer.
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Affiliation(s)
- Jean H Overmeyer
- Department of Biochemistry and Cancer Biology, University of Toledo College of Medicine, Toledo, Ohio 43614, USA
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Vartak N, Bastiaens P. Spatial cycles in G-protein crowd control. EMBO J 2010; 29:2689-99. [PMID: 20717139 PMCID: PMC2924655 DOI: 10.1038/emboj.2010.184] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Accepted: 07/12/2010] [Indexed: 12/19/2022] Open
Abstract
The nature of living systems and their apparent resilience to the second law of thermodynamics has been the subject of extensive investigation and imaginative speculation. The segregation and compartmentalization of proteins is one manifestation of this departure from equilibrium conditions; the effect of which is now beginning to be elucidated. This should not come as a surprise, as even a cursory inspection of cellular processes reveals the large amount of energetic cost borne to maintain cell-scale patterns, separations and gradients of molecules. The G-proteins, kinases, calcium-responsive proteins have all been shown to contain reaction cycles that are inherently coupled to their signalling activities. G-proteins represent an important and diverse toolset used by cells to generate cellular asymmetries. Many small G-proteins in particular, are dynamically acylated to modify their membrane affinities, or localized in an activity-dependent manner, thus manipulating the mobility modes of these proteins beyond pure diffusion and leading to finely tuned steady state partitioning into cellular membranes. The rates of exchange of small G-proteins over various compartments, as well as their steady state distributions enrich and diversify the landscape of possibilities that GTPase-dependent signalling networks can display over cellular dimensions. The chemical manipulation of spatial cycles represents a new approach for the modulation of cellular signalling with potential therapeutic benefits.
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Affiliation(s)
- Nachiket Vartak
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
| | - Philippe Bastiaens
- Department of Systemic Cell Biology, Max Planck Institute for Molecular Physiology, Dortmund, Germany
- Department of Chemistry, University of Dortmund, Dortmund, Germany
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45
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Mihaljevic AL, Michalski CW, Friess H, Kleeff J. Molecular mechanism of pancreatic cancer--understanding proliferation, invasion, and metastasis. Langenbecks Arch Surg 2010; 395:295-308. [PMID: 20237938 DOI: 10.1007/s00423-010-0622-5] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Accepted: 02/16/2010] [Indexed: 12/15/2022]
Abstract
INTRODUCTION The purpose of this review is to highlight the molecular mechanisms leading to the development and progression of pancreatic ductal adenocarcinoma (PDAC) with particular emphasis on tumor cell proliferation, local invasion, and metastasis. Recent advances in the field of PDAC biology have shed light on the molecular events that trigger PDAC initiation and maintenance. RESULTS It is now clear that apart from the genetic alterations within the tumor cells, interactions of the tumor with its environment are necessary for proliferation and invasion. Interestingly, a number of developmental signaling pathways are reactivated in PDAC. Progress has also been made in the understanding of the molecular events that govern the process of metastasis. CONCLUSION Although our understanding of the mechanisms underlying PDAC pathobiology are more advanced than ever, little progress has been made in the clinical treatment of PDAC, and successful bench-to-bedside transfer of knowledge to boost new treatment options is still unsatisfying.
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Affiliation(s)
- André L Mihaljevic
- Chirurgische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaningerstrasse 22, 81675, Munich, Germany
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46
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Mihaljevic AL, Esposito I, Friess H, Kleeff J. Molecular biology, models, and histopathology of chronic pancreatitis and pancreatic cancer. Eur Surg 2009. [DOI: 10.1007/s10353-009-0496-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Duderstadt KE, Berger JM. AAA+ ATPases in the initiation of DNA replication. Crit Rev Biochem Mol Biol 2008; 43:163-87. [PMID: 18568846 DOI: 10.1080/10409230802058296] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
All cellular organisms and many viruses rely on large, multi-subunit molecular machines, termed replisomes, to ensure that genetic material is accurately duplicated for transmission from one generation to the next. Replisome assembly is facilitated by dedicated initiator proteins, which serve to both recognize replication origins and recruit requisite replisomal components to the DNA in a cell-cycle coordinated manner. Exactly how imitators accomplish this task, and the extent to which initiator mechanisms are conserved among different organisms have remained outstanding issues. Recent structural and biochemical findings have revealed that all cellular initiators, as well as the initiators of certain classes of double-stranded DNA viruses, possess a common adenine nucleotide-binding fold belonging to the ATPases Associated with various cellular Activities (AAA+) family. This review focuses on how the AAA+ domain has been recruited and adapted to control the initiation of DNA replication, and how the use of this ATPase module underlies a common set of initiator assembly states and functions. How biochemical and structural properties correlate with initiator activity, and how species-specific modifications give rise to unique initiator functions, are also discussed.
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Affiliation(s)
- Karl E Duderstadt
- Department Molecular and Cell Biology and Biophysics Graduate Group, California Institute for Quantitative Biology, University of California, Berkeley, California 94720-3220, USA.
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Thomsen ND, Berger JM. Structural frameworks for considering microbial protein- and nucleic acid-dependent motor ATPases. Mol Microbiol 2008; 69:1071-90. [PMID: 18647240 DOI: 10.1111/j.1365-2958.2008.06364.x] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Many fundamental cellular processes depend on enzymes that utilize chemical energy to catalyse unfavourable reactions. Certain classes of ATPases provide a particularly vivid example of the process of energy conversion, employing cycles of nucleotide turnover to move and/or rearrange biological polymers such as proteins and nucleic acids. Four well-characterized classes of ATP-dependent protein/nucleic acid translocases and remodelling factors are found in all three domains of life (bacteria, archaea and eukarya): additional strand catalytic 'E' (ASCE) P-loop NTPases, GHL proteins, actin-fold enzymes and chaperonins. These unrelated protein superfamilies have each evolved the ability to couple ATP binding and hydrolysis to the generation of motion and force along or within their substrates. The past several years have witnessed the emergence of a wealth of structural data that help explain how such molecular engines link nucleotide turnover to conformational change. In this review, we highlight several recent advances to illustrate some of the mechanisms by which each family of ATP-dependent motors facilitates the rearrangement and movement of proteins, protein complexes and nucleic acids.
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Affiliation(s)
- Nathan D Thomsen
- Quantitative Biology Institute and Department of Molecular and Cell Biology, 374D Stanley Hall #3220, University of California at Berkeley, Berkeley, CA 94720, USA
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Role of the arginine finger in Ras.RasGAP revealed by QM/MM calculations. FEBS Lett 2007; 581:5677-84. [PMID: 18022389 DOI: 10.1016/j.febslet.2007.11.026] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 10/12/2007] [Accepted: 11/07/2007] [Indexed: 11/21/2022]
Abstract
In the Ras.Ras.GAP complex, hydrolysis of guanosine triphosphate is strongly accelerated GAP as compared to Ras alone. This is largely attributed to the arginine finger R789(GAP) pointing to AlF(x) in the transition state analogue. We performed QM/MM simulations where triphosphate was treated using the quantum mechanical method of density functional theory, while the protein complex and water environment were described classically using MD. Compared to Ras, the crucial electron shift, bond stretching and distortion towards an eclipsed gamma-to-beta orientation are much more pronounced. The arginine finger is shown to act by displacing water out of the binding niche. The resulting enhanced electrostatic field catalyses the cleavage step.
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Abstract
YsxC is a small GTPase of Bacillus subtilis with essential but still unknown function, although recent works have suggested that it might be involved in ribosome biogenesis. Here, purified YsxC overexpressed in Escherichia coli was found to be partly associated with high-molecular-weight material, most likely rRNA, and thus eluted from gel filtration as a large complex. In addition, purification of ribosomes from an E. coli strain overexpressing YsxC allowed the copurification of the YsxC protein. Purified YsxC was shown to bind preferentially to the 50S subunit of B. subtilis ribosomes; this interaction was modulated by nucleotides and was stronger in the presence of a nonhydrolyzable GTP analogue than with GTP. Far-Western blotting analysis performed with His(6)-YsxC and ribosomal proteins separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed that YsxC interacted with at least four ribosomal proteins from the 50S subunit. Two of these putative protein partners were identified by mass spectrometry as L1 and L3, while the third reactive band in the one-dimensional gel contained L6 and L10. The fourth band that reacted with YsxC contained a mixture of three proteins, L7/L12, L23, and L27, suggesting that at least one of them binds to YsxC. Coimmobilization assays confirmed that L1, L6, and L7/L12 interact with YsxC. Together, these results suggest that YsxC plays a role in ribosome assembly.
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