1
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Hutchins CM, Gorfe AA. From disorder comes function: Regulation of small GTPase function by intrinsically disordered lipidated membrane anchor. Curr Opin Struct Biol 2024; 87:102869. [PMID: 38943706 DOI: 10.1016/j.sbi.2024.102869] [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: 04/15/2024] [Revised: 05/23/2024] [Accepted: 06/04/2024] [Indexed: 07/01/2024]
Abstract
The intrinsically disordered, lipid-modified membrane anchor of small GTPases is emerging as a critical modulator of function through its ability to sort lipids in a conformation-dependent manner. We reviewed recent computational and experimental studies that have begun to shed light on the sequence-ensemble-function relationship in this unique class of lipidated intrinsically disordered regions (LIDRs).
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Affiliation(s)
- Chase M Hutchins
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, 6431 Fannin St., Houston, TX 77030, USA; Biochemistry and Cell Biology Program & Therapeutics and Pharmacology Program, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, 6431 Fannin St., Houston, TX 77030, USA. https://twitter.com/chasedsims
| | - Alemayehu A Gorfe
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, 6431 Fannin St., Houston, TX 77030, USA; Biochemistry and Cell Biology Program & Therapeutics and Pharmacology Program, MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, 6431 Fannin St., Houston, TX 77030, USA.
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2
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Jin H, Liu D, Ni Y, Wang H, Long D. Quantitative Ensemble Interpretation of Membrane Paramagnetic Relaxation Enhancement (mPRE) for Studying Membrane-Associated Intrinsically Disordered Proteins. J Am Chem Soc 2024; 146:791-800. [PMID: 38146836 DOI: 10.1021/jacs.3c10847] [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: 12/27/2023]
Abstract
An understanding of the functional role played by a membrane-associated intrinsically disordered protein (IDP) requires characterization of its heterogeneous conformations as well as its poses relative to the membranes, which is of great interest but technically challenging. Here, we explore the membrane paramagnetic relaxation enhancement (mPRE) for constructing ensembles of IDPs that dynamically associate with membrane mimetics incorporating spin-labeled lipids. To accurately interpret the mPRE Γ2 rates, both the dynamics of IDPs and spin probe molecules are taken into account, with the latter described by a weighted three-dimensional (3D) grid model built based on all-atom simulations. The IDP internal conformations, orientations, and immersion depths in lipid bilayers are comprehensively optimized in the Γ2-based ensemble modeling. Our approach is tested and validated on the example of POPG bicelle-bound disordered cytoplasmic domain of CD3ε (CD3εCD), a component of the T-cell receptor (TCR) complex. The mPRE-derived CD3εCD ensemble provides new insights into the IDP-membrane fuzzy association, in particular for the tyrosine-based signaling motif that plays a critical role in TCR signaling. The comparative analysis of the ensembles for wild-type CD3εCD and mutants that mimic the mono- and dual-phosphorylation effects suggests a delicate membrane regulatory mechanism for activation and inhibition of the TCR activity.
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Affiliation(s)
- Hong Jin
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Dan Liu
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Yu Ni
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Hui Wang
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Dong Long
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
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3
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Ikari M, Yagi H, Kasai T, Inomata K, Ito M, Higuchi K, Matsuda N, Ito Y, Kigawa T. Direct Observation of Membrane-Associated H-Ras in the Native Cellular Environment by In-Cell 19F-NMR Spectroscopy. JACS AU 2023; 3:1658-1669. [PMID: 37388687 PMCID: PMC10302746 DOI: 10.1021/jacsau.3c00108] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 05/15/2023] [Accepted: 05/15/2023] [Indexed: 07/01/2023]
Abstract
Ras acts as a molecular switch to control intracellular signaling on the plasma membrane (PM). Elucidating how Ras associates with PM in the native cellular environment is crucial for understanding its control mechanism. Here, we used in-cell nuclear magnetic resonance (NMR) spectroscopy combined with site-specific 19F-labeling to explore the membrane-associated states of H-Ras in living cells. The site-specific incorporation of p-trifluoromethoxyphenylalanine (OCF3Phe) at three different sites of H-Ras, i.e., Tyr32 in switch I, Tyr96 interacting with switch II, and Tyr157 on helix α5, allowed the characterization of their conformational states depending on the nucleotide-bound states and an oncogenic mutational state. Exogenously delivered 19F-labeled H-Ras protein containing a C-terminal hypervariable region was assimilated via endogenous membrane-trafficking, enabling proper association with the cell membrane compartments. Despite poor sensitivity of the in-cell NMR spectra of membrane-associated H-Ras, the Bayesian spectral deconvolution identified distinct signal components on three 19F-labeled sites, thus offering the conformational multiplicity of H-Ras on the PM. Our study may be helpful in elucidating the atomic-scale picture of membrane-associated proteins in living cells.
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Affiliation(s)
- Masaomi Ikari
- RIKEN
Center for Biosystems Dynamics Research, Kanagawa 230-0045, Japan
| | - Hiromasa Yagi
- RIKEN
Center for Biosystems Dynamics Research, Kanagawa 230-0045, Japan
| | - Takuma Kasai
- RIKEN
Center for Biosystems Dynamics Research, Kanagawa 230-0045, Japan
- PRESTO/Japan
Science and Technology Agency, Saitama 332-0012, Japan
| | - Kohsuke Inomata
- RIKEN
Center for Biosystems Dynamics Research, Kanagawa 230-0045, Japan
- PRESTO/Japan
Science and Technology Agency, Saitama 332-0012, Japan
| | - Masahiro Ito
- RIKEN
Center for Biosystems Dynamics Research, Kanagawa 230-0045, Japan
| | - Kae Higuchi
- RIKEN
Center for Biosystems Dynamics Research, Kanagawa 230-0045, Japan
| | - Natsuko Matsuda
- RIKEN
Center for Biosystems Dynamics Research, Kanagawa 230-0045, Japan
- SI Innovation
Center, Taiyo Nippon Sanso Corporation, Tokyo 206-0001, Japan
| | - Yutaka Ito
- Department
of Chemistry, Graduate School of Science, Tokyo Metropolitan University, Tokyo 192-0397, Japan
| | - Takanori Kigawa
- RIKEN
Center for Biosystems Dynamics Research, Kanagawa 230-0045, Japan
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4
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Gu X, Liu D, Yu Y, Wang H, Long D. Quantitative Paramagnetic NMR-Based Analysis of Protein Orientational Dynamics on Membranes: Dissecting the KRas4B-Membrane Interactions. J Am Chem Soc 2023; 145:10295-10303. [PMID: 37116086 DOI: 10.1021/jacs.3c01597] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
Abstract
Peripheral membrane proteins can adopt distinct orientations on the surfaces of lipid bilayers that are often short-lived and challenging to characterize by conventional experimental methods. Here we describe a robust approach for mapping protein orientational landscapes through quantitative interpretation of paramagnetic relaxation enhancement (PRE) data arising from membrane mimetics with spin-labeled lipids. Theoretical analysis, followed by experimental verification, reveals insights into the distinct properties of the PRE observables that are generally distorted in the case of stably membrane-anchored proteins. To suppress the artifacts, we demonstrate that undistorted Γ2 values can be obtained via transient membrane anchoring, based on which a computational framework is established for deriving accurate orientational ensembles obeying Boltzmann statistics. Application of the approach to KRas4B, a classical peripheral membrane protein whose orientations are critical for its functions and drug design, reveals four distinct orientational states that are close but not identical to those reported previously. Similar orientations are also found for a truncated KRas4B without the hypervariable region (HVR) that can sample a broader range of orientations, suggesting a confinement role of the HVR geometrically prohibiting severe tilting. Comparison of the KRas4B Γ2 rates measured using nanodiscs containing different types of anionic lipids reveals identical Γ2 patterns for the G-domain but different ones for the HVR, indicating only the latter is able to selectively interact with anionic lipids.
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Affiliation(s)
- Xue Gu
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Dan Liu
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Yongkui Yu
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Hui Wang
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
| | - Dong Long
- MOE Key Laboratory for Cellular Dynamics, School of Life Sciences, University of Science and Technology of China, Hefei 230027, China
- Department of Chemistry, University of Science and Technology of China, Hefei 230026, China
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5
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Prakash P, Gorfe AA. Determinants of Membrane Orientation Dynamics in Lipid-Modified Small GTPases. JACS AU 2022; 2:128-135. [PMID: 35098229 PMCID: PMC8790735 DOI: 10.1021/jacsau.1c00426] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Indexed: 05/30/2023]
Abstract
The transient membrane engagement and reorientation of the soluble catalytic domain of Ras proteins has emerged as an important modulator of their functions. However, there has been limited information on whether this phenomenon is applicable to other members of the Ras superfamily. To address this issue, we conducted long-time-scale atomistic molecular dynamics simulations (55 μs aggregate simulation time) on representatives of the Ras, Rho, and Arf family proteins that differ in sequence, lipid modification, and the rigidity of the linker between the lipid anchor and the catalytic G-domain. The results show that the concept of membrane reorientation is generalizable to most but not all members of the Ras superfamily. Specifically, C-terminally prenylated small GTPases that are anchored to membranes via a single flexible linker adopt multiple orientations, whereas those that are N-terminally myristoylated and harbor a rigid linker experience limited orientational dynamics. Combined with published reports on Ras proteins, these observations provide insights into the common principles and determinants of the orientational dynamics of lipidated small GTPases on membrane surfaces and offer new ways of thinking about the regulation and druggability of the Ras superfamily proteins.
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6
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Yin G, Lv G, Zhang J, Jiang H, Lai T, Yang Y, Ren Y, Wang J, Yi C, Chen H, Huang Y, Xiao C. Early-stage structure-based drug discovery for small GTPases by NMR spectroscopy. Pharmacol Ther 2022; 236:108110. [PMID: 35007659 DOI: 10.1016/j.pharmthera.2022.108110] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 01/04/2022] [Accepted: 01/05/2022] [Indexed: 12/13/2022]
Abstract
Small GTPase or Ras superfamily, including Ras, Rho, Rab, Ran and Arf, are fundamental in regulating a wide range of cellular processes such as growth, differentiation, migration and apoptosis. They share structural and functional similarities for binding guanine nucleotides and hydrolyzing GTP. Dysregulations of Ras proteins are involved in the pathophysiology of multiple human diseases, however there is still a stringent need for effective treatments targeting these proteins. For decades, small GTPases were recognized as 'undruggable' targets due to their complex regulatory mechanisms and lack of deep pockets for ligand binding. NMR has been critical in deciphering the structural and dynamic properties of the switch regions that are underpinning molecular switch functions of small GTPases, which pave the way for developing new effective inhibitors. The recent progress of drug or lead molecule development made for small GTPases profoundly delineated how modern NMR techniques reshape the field of drug discovery. In this review, we will summarize the progress of structural and dynamic studies of small GTPases, the NMR techniques developed for structure-based drug screening and their applications in early-stage drug discovery for small GTPases.
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Affiliation(s)
- Guowei Yin
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen 518107, China.
| | - Guohua Lv
- Division of Histology & Embryology, Medical College, Jinan University, Guangzhou 511486, Guangdong, China
| | - Jerry Zhang
- University of North Carolina at Chapel Hill School of Medicine, Chapel Hill, NC 27516, USA
| | - Hongmei Jiang
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen 518107, China
| | - Tianqi Lai
- Division of Histology & Embryology, Medical College, Jinan University, Guangzhou 511486, Guangdong, China
| | - Yushan Yang
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen 518107, China
| | - Yong Ren
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen 518107, China
| | - Jing Wang
- College of Life Sciences, Northwest University, Xi'an 710069, Shaanxi, China
| | - Chenju Yi
- The Seventh Affiliated Hospital of Sun Yat-sen University, Shenzhen 518107, China
| | - Hao Chen
- Key Laboratory of Biomedical Information Engineering of Ministry of Education, Biomedical Informatics & Genomics Center, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, Shaanxi Province 710049, PR China; Research Institute of Xi'an Jiaotong University, Zhejiang, Hangzhou, Zhejiang Province 311215, PR China
| | - Yun Huang
- Howard Hughes Medical Institute, Chevy Chase 20815, MD, USA; Department of Physiology & Biophysics, Weill Cornell Medicine, New York 10065, NY, USA.
| | - Chaoni Xiao
- College of Life Sciences, Northwest University, Xi'an 710069, Shaanxi, China.
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7
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Abstract
Membrane proteins (MPs) play essential roles in numerous cellular processes. Because around 70% of the currently marketed drugs target MPs, a detailed understanding of their structure, binding properties, and functional dynamics in a physiologically relevant environment is crucial for a more detailed understanding of this important protein class. We here summarize the benefits of using lipid nanodiscs for NMR structural investigations and provide a detailed overview of the currently used lipid nanodisc systems as well as their applications in solution-state NMR. Despite the increasing use of other structural methods for the structure determination of MPs in lipid nanodiscs, solution NMR turns out to be a versatile tool to probe a wide range of MP features, ranging from the structure determination of small to medium-sized MPs to probing ligand and partner protein binding as well as functionally relevant dynamical signatures in a lipid nanodisc setting. We will expand on these topics by discussing recent NMR studies with lipid nanodiscs and work out a key workflow for optimizing the nanodisc incorporation of an MP for subsequent NMR investigations. With this, we hope to provide a comprehensive background to enable an informed assessment of the applicability of lipid nanodiscs for NMR studies of a particular MP of interest.
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Affiliation(s)
- Umut Günsel
- Bavarian NMR Center (BNMRZ) at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Strasse 2, 85748 Garching, Germany
| | - Franz Hagn
- Bavarian NMR Center (BNMRZ) at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Strasse 2, 85748 Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764 Neuherberg, Germany
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8
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Intrinsically disordered proteins and membranes: a marriage of convenience for cell signalling? Biochem Soc Trans 2021; 48:2669-2689. [PMID: 33155649 PMCID: PMC7752083 DOI: 10.1042/bst20200467] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2020] [Revised: 10/05/2020] [Accepted: 10/08/2020] [Indexed: 02/07/2023]
Abstract
The structure-function paradigm has guided investigations into the molecules involved in cellular signalling for decades. The peripheries of this paradigm, however, start to unravel when considering the co-operation between proteins and the membrane in signalling processes. Intrinsically disordered regions hold distinct advantages over folded domains in terms of their binding promiscuity, sensitivity to their particular environment and their ease of modulation through post-translational modifications. Low sequence complexity and bias towards charged residues are also favourable for the multivalent electrostatic interactions that occur at the surfaces of lipid bilayers. This review looks at the principles behind the successful marriage between protein disorder and membranes in addition to the role of this partnership in modifying and regulating signalling in cellular processes. The HVR (hypervariable region) of small GTPases is highlighted as a well-studied example of the nuanced role a short intrinsically disordered region can play in the fine-tuning of signalling pathways.
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9
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Maruyama T, Alam JM, Fukuda T, Kageyama S, Kirisako H, Ishii Y, Shimada I, Ohsumi Y, Komatsu M, Kanki T, Nakatogawa H, Noda NN. Membrane perturbation by lipidated Atg8 underlies autophagosome biogenesis. Nat Struct Mol Biol 2021; 28:583-593. [PMID: 34239122 DOI: 10.1038/s41594-021-00614-5] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Accepted: 05/26/2021] [Indexed: 02/06/2023]
Abstract
Autophagosome biogenesis is an essential feature of autophagy. Lipidation of Atg8 plays a critical role in this process. Previous in vitro studies identified membrane tethering and hemi-fusion/fusion activities of Atg8, yet definitive roles in autophagosome biogenesis remained controversial. Here, we studied the effect of Atg8 lipidation on membrane structure. Lipidation of Saccharomyces cerevisiae Atg8 on nonspherical giant vesicles induced dramatic vesicle deformation into a sphere with an out-bud. Solution NMR spectroscopy of Atg8 lipidated on nanodiscs identified two aromatic membrane-facing residues that mediate membrane-area expansion and fragmentation of giant vesicles in vitro. These residues also contribute to the in vivo maintenance of fragmented vacuolar morphology under stress in fission yeast, a moonlighting function of Atg8. Furthermore, these aromatic residues are crucial for the formation of a sufficient number of autophagosomes and regulate autophagosome size. Together, these data demonstrate that Atg8 can cause membrane perturbations that underlie efficient autophagosome biogenesis.
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Affiliation(s)
| | | | - Tomoyuki Fukuda
- Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Shun Kageyama
- Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hiromi Kirisako
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
| | - Yuki Ishii
- Institute of Microbial Chemistry, Tokyo, Japan
| | - Ichio Shimada
- Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, Japan.,RIKEN Center for Biosystems Dynamics Research, Yokohama, Japan
| | - Yoshinori Ohsumi
- Cell Biology Center, Institute of Innovative Research, Tokyo Institute of Technology, Yokohama, Japan
| | - Masaaki Komatsu
- Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Tomotake Kanki
- Niigata University Graduate School of Medical and Dental Sciences, Niigata, Japan
| | - Hitoshi Nakatogawa
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama, Japan
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10
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Jirasko V, Lends A, Lakomek N, Fogeron M, Weber ME, Malär AA, Penzel S, Bartenschlager R, Meier BH, Böckmann A. Dimer Organization of Membrane‐Associated NS5A of Hepatitis C Virus as Determined by Highly Sensitive
1
H‐Detected Solid‐State NMR. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202013296] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | - Alons Lends
- Physical Chemistry ETH Zurich 8093 Zurich Switzerland
| | | | - Marie‐Laure Fogeron
- Molecular Microbiology and Structural Biochemistry Labex Ecofect UMR 5086 CNRS Université de Lyon 1 7 passage du Vercors 69367 Lyon France
| | | | | | | | - Ralf Bartenschlager
- Department of Infectious Diseases Molecular Virology Heidelberg University Im Neuenheimer Feld 345 69120 Heidelberg Germany
- German Centre for Infection Research (DZIF) Heidelberg partner site Heidelberg Germany
| | - Beat H. Meier
- Physical Chemistry ETH Zurich 8093 Zurich Switzerland
| | - Anja Böckmann
- Molecular Microbiology and Structural Biochemistry Labex Ecofect UMR 5086 CNRS Université de Lyon 1 7 passage du Vercors 69367 Lyon France
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11
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Jirasko V, Lends A, Lakomek N, Fogeron M, Weber ME, Malär AA, Penzel S, Bartenschlager R, Meier BH, Böckmann A. Dimer Organization of Membrane-Associated NS5A of Hepatitis C Virus as Determined by Highly Sensitive 1 H-Detected Solid-State NMR. Angew Chem Int Ed Engl 2021; 60:5339-5347. [PMID: 33205864 PMCID: PMC7986703 DOI: 10.1002/anie.202013296] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2020] [Revised: 11/17/2020] [Indexed: 12/17/2022]
Abstract
The Hepatitis C virus nonstructural protein 5A (NS5A) is a membrane-associated protein involved in multiple steps of the viral life cycle. Direct-acting antivirals (DAAs) targeting NS5A are a cornerstone of antiviral therapy, but the mode-of-action of these drugs is poorly understood. This is due to the lack of information on the membrane-bound NS5A structure. Herein, we present the structural model of an NS5A AH-linker-D1 protein reconstituted as proteoliposomes. We use highly sensitive proton-detected solid-state NMR methods suitable to study samples generated through synthetic biology approaches. Spectra analyses disclose that both the AH membrane anchor and the linker are highly flexible. Paramagnetic relaxation enhancements (PRE) reveal that the dimer organization in lipids requires a new type of NS5A self-interaction not reflected in previous crystal structures. In conclusion, we provide the first characterization of NS5A AH-linker-D1 in a lipidic environment shedding light onto the mode-of-action of clinically used NS5A inhibitors.
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Affiliation(s)
| | - Alons Lends
- Physical ChemistryETH Zurich8093ZurichSwitzerland
| | | | - Marie‐Laure Fogeron
- Molecular Microbiology and Structural BiochemistryLabex EcofectUMR 5086 CNRSUniversité de Lyon 17 passage du Vercors69367LyonFrance
| | | | | | | | - Ralf Bartenschlager
- Department of Infectious DiseasesMolecular VirologyHeidelberg UniversityIm Neuenheimer Feld 34569120HeidelbergGermany
- German Centre for Infection Research (DZIF)Heidelberg partner siteHeidelbergGermany
| | | | - Anja Böckmann
- Molecular Microbiology and Structural BiochemistryLabex EcofectUMR 5086 CNRSUniversité de Lyon 17 passage du Vercors69367LyonFrance
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12
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Biochemical and NMR characterization of the interactions of Vav2-SH2 domain with lipids and the EphA2 juxtamembrane region on membrane. Biochem J 2021; 477:3791-3801. [PMID: 32897354 DOI: 10.1042/bcj20200300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 09/05/2020] [Accepted: 09/07/2020] [Indexed: 12/21/2022]
Abstract
Vav2 is a ubiquitous guanine nucleotide exchange factor (GEF) for Rho family GTPases that is involved in regulating a wide range of biological processes. It interacts with several tyrosine-phosphorylated cell surface receptors, including the Eph family receptors, through its SH2 domain. The interaction of Vav2 with EphA2 is crucial for EphA2-mediated tumor angiogenesis. Here we show that Vav2-SH2 domain is a lipid-binding module that can recognize PI(4,5)P2 and PI(3,4,5)P3 lipids weakly but specifically. The specific lipid-binding site in Vav2-SH2 domain was identified by NMR chemical shift perturbation experiments using the head groups of PI(4,5)P2 and PI(3,4,5)P3, both of which bind to Vav2-SH2 with millimolar binding affinities. In addition, the interaction between Vav2-SH2 and the phosphorylated juxtamembrane region (JM) of EphA2 (Y594 phosphorylated) was investigated using NMR techniques. Furthermore, by using a nickel-lipid containing peptide-based nanodiscs system, we studied the binding of Vav2-SH2 to the phosphorylated JM region of EphA2 on lipid membrane and uncovered a role of membrane environment in modulating this protein-protein recognition.
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13
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Hu Y, Cheng K, He L, Zhang X, Jiang B, Jiang L, Li C, Wang G, Yang Y, Liu M. NMR-Based Methods for Protein Analysis. Anal Chem 2021; 93:1866-1879. [PMID: 33439619 DOI: 10.1021/acs.analchem.0c03830] [Citation(s) in RCA: 33] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a well-established method for analyzing protein structure, interaction, and dynamics at atomic resolution and in various sample states including solution state, solid state, and membranous environment. Thanks to rapid NMR methodology development, the past decade has witnessed a growing number of protein NMR studies in complex systems ranging from membrane mimetics to living cells, which pushes the research frontier further toward physiological environments and offers unique insights in elucidating protein functional mechanisms. In particular, in-cell NMR has become a method of choice for bridging the huge gap between structural biology and cell biology. Herein, we review the recent developments and applications of NMR methods for protein analysis in close-to-physiological environments, with special emphasis on in-cell protein structural determination and the analysis of protein dynamics, both difficult to be accessed by traditional methods.
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Affiliation(s)
- Yunfei Hu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 10049, China
| | - Kai Cheng
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China
| | - Lichun He
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 10049, China
| | - Xu Zhang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 10049, China
| | - Bin Jiang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 10049, China
| | - Ling Jiang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 10049, China
| | - Conggang Li
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 10049, China
| | - Guan Wang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 10049, China
| | - Yunhuang Yang
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 10049, China
| | - Maili Liu
- Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences-Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan 430071, China.,University of Chinese Academy of Sciences, Beijing 10049, China
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14
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Carroll B. Spatial regulation of mTORC1 signalling: Beyond the Rag GTPases. Semin Cell Dev Biol 2020; 107:103-111. [PMID: 32122730 DOI: 10.1016/j.semcdb.2020.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 02/17/2020] [Accepted: 02/20/2020] [Indexed: 12/15/2022]
Abstract
The mechanistic (or mammalian) Target of Rapamycin Complex 1 (mTORC1) is a central regulator of cell growth and metabolism. By integrating mitogenic signals, mTORC1-dependent phosphorylation of substrates dictates the balance between anabolic, pro-growth and catabolic, recycling processes in the cell. The discovery that amino acids activate mTORC1 by promoting its translocation to the lysosome was a fundamental advance in the understanding of mTORC1 signalling. It has since become clear that the lysosome-cytoplasm shuttling of mTORC1 represents just one layer of spatial control of this signalling pathway. This review will focus on exploring the subcellular localisation of mTORC1 and its regulators to multiple sites within the cell. We will discuss how these spatially distinct regions such as endoplasmic reticulum, plasma membrane and the endosomal pathway co-operate to transduce nutrient availability to mTORC1, allowing for tight control of cell growth.
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Affiliation(s)
- Bernadette Carroll
- School of Biochemistry, Biomedical Sciences Building, University Walk, Bristol, BS8, United Kingdom.
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15
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Klöpfer K, Hagn F. Beyond detergent micelles: The advantages and applications of non-micellar and lipid-based membrane mimetics for solution-state NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:271-283. [PMID: 31779883 DOI: 10.1016/j.pnmrs.2019.08.001] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/15/2019] [Revised: 08/20/2019] [Accepted: 08/22/2019] [Indexed: 06/10/2023]
Abstract
Membrane proteins are important players in signal transduction and the exchange of metabolites within or between cells. Thus, this protein class is the target of around 60 % of currently marketed drugs, emphasizing their essential biological role. Besides functional assays, structural and dynamical investigations on this protein class are crucial to fully understanding their functionality. Even though X-ray crystallography and electron microscopy are the main methods to determine structures of membrane proteins and their complexes, NMR spectroscopy can contribute essential information on systems that (a) do not crystallize and (b) are too small for EM. Furthermore, NMR is a versatile tool for monitoring functional dynamics of biomolecules at various time scales. A crucial aspect of such studies is the use of a membrane mimetic that resembles a native environment and thus enables the extraction of functional insights. In recent decades, the membrane protein NMR community has moved from rather harsh detergents to membrane systems having more native-like properties. In particular, most recently phospholipid nanodiscs have been developed and optimized mainly for solution-state NMR but are now also being used for solid-state NMR spectroscopy. Nanodiscs consist of a patch of a planar lipid bilayer that is encircled by different (bio-)polymers to form particles of defined and tunable size. In this review, we provide an overview of available membrane mimetics, including nanodiscs, amphipols and bicelles, that are suitable for high-resolution NMR spectroscopy and describe how these advanced membrane mimetics can facilitate NMR studies on the structure and dynamics of membrane proteins. Since the stability of membrane proteins depends critically on the chosen membrane mimetic, we emphasize the importance of a suitable system that is not necessarily developed for solution-state NMR applications and hence requires optimization for each membrane protein. However, lipid-based membrane mimetics offer the possibility of performing NMR experiments at elevated temperatures and studying ligand and partner protein complexes as well as their functional dynamics in a realistic membrane environment. In order to be able to make an informed decision during the selection of a suitable membrane system, we provide a detailed overview of the available options for various membrane protein classes and thereby facilitate this often-difficult selection process for a broad range of desired NMR applications.
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Affiliation(s)
- Kai Klöpfer
- Bavarian NMR Center at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85747 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany
| | - Franz Hagn
- Bavarian NMR Center at the Department of Chemistry, Technical University of Munich, Ernst-Otto-Fischer-Str. 2, 85747 Garching, Germany; Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764 Neuherberg, Germany.
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16
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Killoran RC, Smith MJ. Conformational resolution of nucleotide cycling and effector interactions for multiple small GTPases determined in parallel. J Biol Chem 2019; 294:9937-9948. [PMID: 31088913 DOI: 10.1074/jbc.ra119.008653] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2019] [Revised: 05/09/2019] [Indexed: 12/31/2022] Open
Abstract
Small GTPases alternatively bind GDP/GTP guanine nucleotides to gate signaling pathways that direct most cellular processes. Numerous GTPases are implicated in oncogenesis, particularly the three RAS isoforms HRAS, KRAS, and NRAS and the RHO family GTPase RAC1. Signaling networks comprising small GTPases are highly connected, and there is some evidence of direct biochemical cross-talk between their functional G-domains. The activation potential of a given GTPase is contingent on a codependent interaction with the nucleotide and a Mg2+ ion, which bind to individual variants with distinct affinities coordinated by residues in the GTPase nucleotide-binding pocket. Here, we utilized a selective-labeling strategy coupled with real-time NMR spectroscopy to monitor nucleotide exchange, GTP hydrolysis, and effector interactions of multiple small GTPases in a single complex system. We provide insight into nucleotide preference and the role of Mg2+ in activating both WT and oncogenic mutant enzymes. Multiplexing revealed guanine nucleotide exchange factor (GEF), GTPase-activating protein (GAP), and effector-binding specificities in mixtures of GTPases and resolved that the three related RAS isoforms are biochemically equivalent. This work establishes that direct quantitation of the nucleotide-bound conformation is required to accurately determine an activation potential for any given GTPase, as small GTPases such as RAS-like proto-oncogene A (RALA) or the G12C mutant of KRAS display fast exchange kinetics but have a high affinity for GDP. Furthermore, we propose that the G-domains of small GTPases behave autonomously in solution and that nucleotide cycling proceeds independently of protein concentration but is highly impacted by Mg2+ abundance.
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Affiliation(s)
- Ryan C Killoran
- From the Institute for Research in Immunology and Cancer and
| | - Matthew J Smith
- From the Institute for Research in Immunology and Cancer and .,Department of Pathology and Cell Biology, Faculty of Medicine, Université de Montréal, Montréal, Québec H3T 1J4, Canada
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17
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Cao S, Chung S, Kim S, Li Z, Manor D, Buck M. K-Ras G-domain binding with signaling lipid phosphatidylinositol (4,5)-phosphate (PIP2): membrane association, protein orientation, and function. J Biol Chem 2019; 294:7068-7084. [PMID: 30792310 DOI: 10.1074/jbc.ra118.004021] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 12/12/2018] [Indexed: 12/14/2022] Open
Abstract
Ras genes potently drive human cancers, with mutated proto-oncogene GTPase KRAS4B (K-Ras4B) being the most abundant isoform. Targeted inhibition of oncogenic gene products is considered the "holy grail" of present-day cancer therapy, and recent discoveries of small-molecule KRas4B inhibitors were made thanks to a deeper understanding of the structure and dynamics of this GTPase. Because interactions with biological membranes are key for Ras function, Ras-lipid interactions have become a major focus, especially because such interactions evidently involve both the Ras C terminus for lipid anchoring and its G-protein domain. Here, using NMR spectroscopy and molecular dynamics simulations complemented by biophysical- and cell-biology assays, we investigated the interaction between K-Ras4B with the signaling lipid phosphatidylinositol (4,5)-phosphate (PIP2). We discovered that the β2 and β3 strands as well as helices 4 and 5 of the GTPase G-domain bind to PIP2 and identified the specific residues in these structural elements employed in these interactions, likely occurring in two K-Ras4B orientation states relative to the membrane. Importantly, we found that some of these residues known to be oncogenic when mutated (D47K, D92N, K104M, and D126N) are critical for K-Ras-mediated transformation of fibroblast cells, but do not substantially affect basal and assisted nucleotide hydrolysis and exchange. Moreover, the K104M substitution abolished localization of K-Ras to the plasma membrane. The findings suggest that specific G-domain residues can critically regulate Ras function by mediating interactions with membrane-associated PIP2 lipids; these insights that may inform the future design of therapeutic reagents targeting Ras activity.
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Affiliation(s)
- Shufen Cao
- From the Departments of Physiology and Biophysics
| | | | | | - Zhenlu Li
- From the Departments of Physiology and Biophysics
| | - Danny Manor
- Nutrition, .,Pharmacology, and.,the Case Comprehensive Cancer Center and
| | - Matthias Buck
- From the Departments of Physiology and Biophysics, .,the Case Comprehensive Cancer Center and.,Neurosciences, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106 and.,Center for Proteomics and Bioinformatics, Case Western Reserve University, School of Medicine, Cleveland, Ohio 44106
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18
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Li Y, Soubias O, Li J, Sun S, Randazzo PA, Byrd RA. Functional Expression and Characterization of Human Myristoylated-Arf1 in Nanodisc Membrane Mimetics. Biochemistry 2019; 58:1423-1431. [PMID: 30735034 DOI: 10.1021/acs.biochem.8b01323] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Lipidated small GTP-binding proteins of the Arf family interact with multiple cellular partners and with membranes to regulate intracellular traffic and organelle structure. Here, we focus on the ADP-ribosylation factor 1 (Arf1), which interacts with numerous proteins in the Arf pathway, such as the ArfGAP ASAP1 that is highly expressed and activated in several cancer cell lines and associated with enhanced migration, invasiveness, and poor prognosis. Understanding the molecular and mechanistic details of Arf1 regulation at the membrane via structural and biophysical studies requires large quantities of fully functional protein bound to lipid bilayers. Here, we report on the production of a functional human Arf1 membrane platform on nanodiscs for biophysical studies. Large scale bacterial production of highly pure, N-myristoylated human Arf1 has been achieved, including complex isotopic labeling for nuclear magnetic resonance (NMR) studies, and the myr-Arf1 can be readily assembled in small nanoscale lipid bilayers (nanodiscs, NDs). It is determined that myr-Arf1 requires a minimum binding surface in the NDs of ∼20 lipids. Fluorescence and NMR were used to establish nucleotide exchange and ArfGAP-stimulated GTP hydrolysis at the membrane, indicating that phophoinositide stimulation of the activity of the ArfGAP ASAP1 is ≥2000-fold. Differences in nonhydrolyzable GTP analogues are observed, and GMPPCP is found to be the most stable. Combined, these observations establish a functional environment for biophysical studies of Arf1 effectors and interactions at the membrane.
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Affiliation(s)
- Yifei Li
- Structural Biophysics Laboratory, Center for Cancer Research , National Cancer Institute , Frederick , Maryland 21702-1201 , United States
| | - Olivier Soubias
- Structural Biophysics Laboratory, Center for Cancer Research , National Cancer Institute , Frederick , Maryland 21702-1201 , United States
| | - Jess Li
- Structural Biophysics Laboratory, Center for Cancer Research , National Cancer Institute , Frederick , Maryland 21702-1201 , United States
| | - Shangjin Sun
- Structural Biophysics Laboratory, Center for Cancer Research , National Cancer Institute , Frederick , Maryland 21702-1201 , United States
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, Center for Cancer Research , National Cancer Institute , Bethesda , Maryland 20892 , United States
| | - R Andrew Byrd
- Structural Biophysics Laboratory, Center for Cancer Research , National Cancer Institute , Frederick , Maryland 21702-1201 , United States
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19
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Three distinct regions of cRaf kinase domain interact with membrane. Sci Rep 2019; 9:2057. [PMID: 30765804 PMCID: PMC6375958 DOI: 10.1038/s41598-019-38770-w] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Accepted: 12/19/2018] [Indexed: 12/18/2022] Open
Abstract
Raf kinases are downstream effectors of small GTPase Ras. Mutations in Ras and Raf are associated with a variety of cancers and genetic disorders. Of the three Raf isoforms, cRaf is most frequently involved in tumor initiation by Ras. Cytosolic Raf is auto-inhibited and becomes active upon recruitment to the plasma membrane. Since the catalytic domain of Raf is its kinase domain, we ask the following: does the kinase domain of Raf has potential to interact with membrane and if yes, what role does the membrane interaction play? We present a model of cRaf kinase domain in complex with a heterogeneous membrane bilayer using atomistic molecular dynamics simulation. We show that the kinase domain of cRaf has three distinct membrane-interacting regions: a polybasic motif (R.RKTR) from the regulatory αC-helix, an aromatic/hydrophobic cluster from the N-terminal acidic region (NtA) and positively charged/aromatic cluster from the activation segment (AS). We show that residues from these regions form an extended membrane-interacting surface that resembles the membrane-interacting residues from known membrane-binding domains. Activating phosphorylatable regions (NtA and AS), make direct contact with the membrane whereas R.RKTR forms specific multivalent salt bridges with PA. PA lipids dwell for longer times around the R.RKTR motif. Our results suggest that membrane interaction of monomeric cRaf kinase domain likely orchestrates the Raf activation process and modulates its function. We show that R.RKTR is a hotspot that interacts with membrane when cRaf is monomeric and becomes part of the interface upon Raf dimerization. We propose that in terms of utilizing a specific hotspot to form membrane interaction and dimer formation, both Raf and its upstream binding partner KRas, are similar.
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20
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Marcink TC, Simoncic JA, An B, Knapinska AM, Fulcher YG, Akkaladevi N, Fields GB, Van Doren SR. MT1-MMP Binds Membranes by Opposite Tips of Its β Propeller to Position It for Pericellular Proteolysis. Structure 2018; 27:281-292.e6. [PMID: 30471921 DOI: 10.1016/j.str.2018.10.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 08/08/2018] [Accepted: 10/10/2018] [Indexed: 02/08/2023]
Abstract
Critical to migration of tumor cells and endothelial cells is the proteolytic attack of membrane type 1 matrix metalloproteinase (MT1-MMP) upon collagen, growth factors, and receptors at cell surfaces. Lipid bilayer interactions of the substrate-binding hemopexin-like (HPX) domain of MT1-MMP were investigated by paramagnetic nuclear magnetic resonance relaxation enhancements (PREs), fluorescence, and mutagenesis. The HPX domain binds bilayers by blades II and IV on opposite sides of its β propeller fold. The EPGYPK sequence protruding from both blades inserts among phospholipid head groups in PRE-restrained molecular dynamics simulations. Bilayer binding to either blade II or IV exposes the CD44 binding site in blade I. Bilayer association with blade IV allows the collagen triple helix to bind without obstruction. Indeed, vesicles enhance proteolysis of collagen triple-helical substrates by the ectodomain of MT1-MMP. Hypothesized side-by-side MT1-MMP homodimerization would allow binding of bilayers, collagen, CD44, and head-to-tail oligomerization.
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Affiliation(s)
- Tara C Marcink
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA
| | - Jayce A Simoncic
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA
| | - Bo An
- Departments of Biomedical Engineering and Chemistry, Tufts University, Medford, MA 02155, USA
| | - Anna M Knapinska
- Department of Chemistry & Biochemistry, Florida Atlantic University, Jupiter, FL 33458, USA; Department of Chemistry, The Scripps Research Institute/Scripps Florida, Jupiter, FL 33458, USA
| | - Yan G Fulcher
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA
| | - Narahari Akkaladevi
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA
| | - Gregg B Fields
- Department of Chemistry & Biochemistry, Florida Atlantic University, Jupiter, FL 33458, USA; Department of Chemistry, The Scripps Research Institute/Scripps Florida, Jupiter, FL 33458, USA
| | - Steven R Van Doren
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO 65211, USA.
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21
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Raltchev K, Pipercevic J, Hagn F. Production and Structural Analysis of Membrane-Anchored Proteins in Phospholipid Nanodiscs. Chemistry 2018; 24:5493-5499. [DOI: 10.1002/chem.201800812] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2018] [Indexed: 01/03/2023]
Affiliation(s)
- Kolio Raltchev
- Bavarian NMR Center at the Department of Chemistry and Institute for Advanced Study; Technical University of Munich; Lichtenbergstrasse 4 85747 Garching Germany
- Institute of Structural Biology; Helmholtz Zentrum München; Ingolstädter Landstrasse 1 85764 Neuherberg Germany
| | - Joka Pipercevic
- Bavarian NMR Center at the Department of Chemistry and Institute for Advanced Study; Technical University of Munich; Lichtenbergstrasse 4 85747 Garching Germany
- Institute of Structural Biology; Helmholtz Zentrum München; Ingolstädter Landstrasse 1 85764 Neuherberg Germany
| | - Franz Hagn
- Bavarian NMR Center at the Department of Chemistry and Institute for Advanced Study; Technical University of Munich; Lichtenbergstrasse 4 85747 Garching Germany
- Institute of Structural Biology; Helmholtz Zentrum München; Ingolstädter Landstrasse 1 85764 Neuherberg Germany
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22
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De Cicco M, Kiss L, Dames SA. NMR analysis of the backbone dynamics of the small GTPase Rheb and its interaction with the regulatory protein FKBP38. FEBS Lett 2017; 592:130-146. [PMID: 29194576 DOI: 10.1002/1873-3468.12925] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2017] [Revised: 10/06/2017] [Accepted: 11/17/2017] [Indexed: 12/19/2022]
Abstract
Ras homolog enriched in brain (Rheb) is a small GTPase that regulates mammalian/mechanistic target of rapamycin complex 1 (mTORC1) and, thereby, cell growth and metabolism. Here we show that cycling between the inactive GDP- and the active GTP-bound state modulates the backbone dynamics of a C-terminal truncated form, RhebΔCT, which is suggested to influence its interactions. We further investigated the interactions between RhebΔCT and the proposed Rheb-binding domain of the regulatory protein FKBP38. The observed weak interactions with the GTP-analogue- (GppNHp-) but not the GDP-bound state, appear to accelerate the GDP to GTP exchange, but only very weakly compared to a genuine GEF. Thus, FKBP38 is most likely not a GEF but a Rheb effector that may function in membrane targeting of Rheb.
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Affiliation(s)
- Maristella De Cicco
- Technische Universität München, Department of Chemistry, Biomolecular NMR Spectroscopy, Garching, Germany
| | - Leo Kiss
- Technische Universität München, Department of Chemistry, Biomolecular NMR Spectroscopy, Garching, Germany
| | - Sonja A Dames
- Technische Universität München, Department of Chemistry, Biomolecular NMR Spectroscopy, Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany
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23
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Assembly of phospholipid nanodiscs of controlled size for structural studies of membrane proteins by NMR. Nat Protoc 2017; 13:79-98. [PMID: 29215632 DOI: 10.1038/nprot.2017.094] [Citation(s) in RCA: 130] [Impact Index Per Article: 18.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Suitable membrane mimetics are crucial to the performance of structural and functional studies of membrane proteins. Phospholipid nanodiscs (formed when a membrane scaffold protein encircles a small portion of a lipid bilayer) have native-like membrane properties. These have been used for a variety of functional studies, but structural studies by high-resolution solution-state NMR spectroscopy of membrane proteins in commonly used nanodiscs of 10-nm diameter were limited by the high molecular weight of these particles, which caused unfavorably large NMR line widths. We have recently constructed truncated versions of the membrane scaffold protein, allowing the preparation of a range of stepwise-smaller nanodiscs (6- to 8-nm diameter) to overcome this limitation. Here, we present a protocol on the assembly of phospholipid nanodiscs of various sizes for structural studies of membrane proteins with solution-state NMR spectroscopy. We describe specific isotope-labeling schemes required for working with large membrane protein systems in nanodiscs, and provide guidelines on the setup of NMR non-uniform sampling (NUS) data acquisition and high-resolution NMR spectra reconstruction. We discuss critical points and pitfalls relating to optimization of nanodiscs for NMR spectroscopy and outline a strategy for the high-resolution structure determination and positioning of isotope-labeled membrane proteins in nanodiscs using nuclear Overhauser enhancement spectroscopy (NOESY) spectroscopy, residual dipolar couplings (RDCs) and paramagnetic relaxation enhancements (PREs). Depending on the target protein of interest, nanodisc assembly and purification can be achieved within 12-24 h. Although the focus of this protocol is on protein NMR, these nanodiscs can also be used for (cryo-) electron microscopy (EM) and small-angle X-ray and neutron-scattering studies.
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24
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De Cicco M, Milroy LG, Dames SA. Target of rapamycin FATC domain as a general membrane anchor: The FKBP-12 like domain of FKBP38 as a case study. Protein Sci 2017; 27:546-560. [PMID: 29024217 DOI: 10.1002/pro.3321] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Revised: 10/06/2017] [Accepted: 10/09/2017] [Indexed: 01/11/2023]
Abstract
Increased efforts have been undertaken to better understand the formation of signaling complexes at cellular membranes. Since the preparation of proteins containing a transmembrane domain or a prenylation motif is generally challenging an alternative membrane anchoring unit that is easy to attach, water-soluble and binds to different membrane mimetics would find broad application. The 33-residue long FATC domain of yeast TOR1 (y1fatc) fulfills these criteria and binds to neutral and negatively charged micelles, bicelles, and liposomes. As a case study, we fused it to the FKBP506-binding region of the protein FKBP38 (FKBP38-BD) and used 1 H-15 N NMR spectroscopy to characterize localization of the chimeric protein to micelles, bicelles, and liposomes. Based on these and published data for y1fatc, its use as a C-terminally attachable membrane anchor for other proteins is compatible with a wide range of buffer conditions (pH circa 6-8.5, NaCl 0 to >150 mM, presence of reducing agents, different salts such as MgCl2 and CaCl2 ). The high water-solubility of y1fatc enables its use for titration experiments against a membrane-localized interaction partner of the fused target protein. Results from studies with peptides corresponding to the C-terminal 17-11 residues of the 33-residue long domain by 1D 1 H NMR and CD spectroscopy indicate that they still can interact with membrane mimetics. Thus, they may be used as membrane anchors if the full y1fatc sequence is disturbing or if a chemically synthesized y1fatc peptide shall be attached by native chemical ligation, for example, unlabeled peptide to 15 N-labeled target protein for NMR studies.
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Affiliation(s)
- Maristella De Cicco
- Department of Chemistry, Technische Universität München, Biomolecular NMR Spectroscopy, Garching, Germany
| | - Lech-G Milroy
- Department of Biomedical Technology, Laboratory of Chemical Biology, Technische Universiteit Eindhoven, Eindhoven, The Netherlands
| | - Sonja A Dames
- Department of Chemistry, Technische Universität München, Biomolecular NMR Spectroscopy, Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Neuherberg, Germany
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25
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Rouck J, Krapf J, Roy J, Huff H, Das A. Recent advances in nanodisc technology for membrane protein studies (2012-2017). FEBS Lett 2017; 591:2057-2088. [PMID: 28581067 PMCID: PMC5751705 DOI: 10.1002/1873-3468.12706] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 05/26/2017] [Accepted: 05/31/2017] [Indexed: 01/01/2023]
Abstract
Historically, the main barrier to membrane protein investigations has been the tendency of membrane proteins to aggregate (due to their hydrophobic nature), in aqueous solution as well as on surfaces. The introduction of biomembrane mimetics has since stimulated momentum in the field. One such mimetic, the nanodisc (ND) system, has proved to be an exceptional system for solubilizing membrane proteins. Herein, we critically evaluate the advantages and imperfections of employing nanodiscs in biophysical and biochemical studies. Specifically, we examine the techniques that have been modified to study membrane proteins in nanodiscs. Techniques discussed here include fluorescence microscopy, solution-state/solid-state nuclear magnetic resonance, electron microscopy, small-angle X-ray scattering, and several mass spectroscopy methods. Newer techniques such as SPR, charge-sensitive optical detection, and scintillation proximity assays are also reviewed. Lastly, we cover how nanodiscs are advancing nanotechnology through nanoplasmonic biosensing, lipoprotein-nanoplatelets, and sortase-mediated labeling of nanodiscs.
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Affiliation(s)
- John Rouck
- Department of Biochemistry, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
| | - John Krapf
- Department of Biochemistry, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
| | - Jahnabi Roy
- Department of Chemistry, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
| | - Hannah Huff
- Department of Chemistry, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
| | - Aditi Das
- Department of Comparative Biosciences, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
- Department of Biochemistry, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
- Beckman Institute for Advanced Science, Division of Nutritional Sciences, Neuroscience Program and Department of Bioengineering, University of Illinois Urbana–Champaign, Urbana IL 61802, USA
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26
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Siempelkamp BD, Rathinaswamy MK, Jenkins ML, Burke JE. Molecular mechanism of activation of class IA phosphoinositide 3-kinases (PI3Ks) by membrane-localized HRas. J Biol Chem 2017; 292:12256-12266. [PMID: 28515318 DOI: 10.1074/jbc.m117.789263] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2017] [Revised: 05/06/2017] [Indexed: 12/15/2022] Open
Abstract
Class IA PI3Ks are involved in the generation of the key lipid signaling molecule phosphatidylinositol 3,4,5-trisphosphate (PIP3), and inappropriate activation of this pathway is implicated in a multitude of human diseases, including cancer, inflammation, and primary immunodeficiencies. Class IA PI3Ks are activated downstream of the Ras superfamily of GTPases, and Ras-PI3K interaction plays a key role in promoting tumor formation and maintenance in Ras-driven tumors. Investigating the detailed molecular events in the Ras-PI3K interaction has been challenging because it occurs on a membrane surface. Here, using maleimide-functionalized lipid vesicles, we successfully generated membrane-resident HRas and evaluated its effect on PI3K signaling in lipid kinase assays and through analysis with hydrogen-deuterium exchange MS. We screened all class IA PI3K isoforms and found that HRas activates both p110α and p110δ isoforms but does not activate p110β. The p110α and p110δ activation by Ras was synergistic with activation by a soluble phosphopeptide derived from receptor tyrosine kinases. Hydrogen-deuterium exchange MS revealed that membrane-resident HRas, but not soluble HRas, enhances conformational changes associated with membrane binding by increasing membrane recruitment of both p110α and p110δ. Together, these results afford detailed molecular insight into the Ras-PI3K signaling complex, provide a framework for screening Ras inhibitors, and shed light on the isoform specificity of Ras-PI3K interactions in a native membrane context.
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Affiliation(s)
- Braden D Siempelkamp
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - Manoj K Rathinaswamy
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - Meredith L Jenkins
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 2Y2, Canada.
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27
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B Kumar R, Zhu L, Hebert H, Jegerschöld C. Method to Visualize and Analyze Membrane Interacting Proteins by Transmission Electron Microscopy. J Vis Exp 2017. [PMID: 28287545 DOI: 10.3791/55148] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Monotopic proteins exert their function when attached to a membrane surface, and such interactions depend on the specific lipid composition and on the availability of enough area to perform the function. Nanodiscs are used to provide a membrane surface of controlled size and lipid content. In the absence of bound extrinsic proteins, sodium phosphotungstate-stained nanodiscs appear as stacks of coins when viewed from the side by transmission electron microscopy (TEM). This protocol is therefore designed to intentionally promote stacking; consequently, the prevention of stacking can be interpreted as the binding of the membrane-binding protein to the nanodisc. In a further step, the TEM images of the protein-nanodisc complexes can be processed with standard single-particle methods to yield low-resolution structures as a basis for higher resolution cryoEM work. Furthermore, the nanodiscs provide samples suitable for either TEM or non-denaturing gel electrophoresis. To illustrate the method, Ca2+-induced binding of 5-lipoxygenase on nanodiscs is presented.
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Affiliation(s)
| | - Lin Zhu
- School of Technology and Health, KTH Royal Institute of Technology
| | - Hans Hebert
- Department of Biosciences and Nutrition, Karolinska Institutet; School of Technology and Health, KTH Royal Institute of Technology
| | - Caroline Jegerschöld
- Department of Biosciences and Nutrition, Karolinska Institutet; School of Technology and Health, KTH Royal Institute of Technology; ;
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28
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Oncogenic K-Ras Binds to an Anionic Membrane in Two Distinct Orientations: A Molecular Dynamics Analysis. Biophys J 2016; 110:1125-38. [PMID: 26958889 DOI: 10.1016/j.bpj.2016.01.019] [Citation(s) in RCA: 107] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2015] [Revised: 01/05/2016] [Accepted: 01/11/2016] [Indexed: 01/05/2023] Open
Abstract
K-Ras is a membrane-associated GTPase that cycles between active and inactive conformational states to regulate a variety of cell signaling pathways. Somatic mutations in K-Ras are linked to 15-20% of all human tumors. K-Ras attaches to the inner leaflet of the plasma membrane via a farnesylated polybasic domain; however, the structural details of the complex remain poorly understood. Based on extensive (7.5 μs total) atomistic molecular dynamics simulations here we show that oncogenic mutant K-Ras interacts with a negatively charged lipid bilayer membrane in multiple orientations. Of these, two highly populated orientations account for ∼54% of the conformers whose catalytic domain directly interacts with the bilayer. In one of these orientation states, membrane binding involves helices 3 and 4 of the catalytic domain in addition to the farnesyl and polybasic motifs. In the other orientation, β-strands 1-3 and helix 2 on the opposite face of the catalytic domain contribute to membrane binding. Flexibility of the linker region was found to be important for the reorientation. The biological significance of these observations was evaluated by initial experiments in cells overexpressing mutant K-Ras as well as by an analysis of Ras-effector complex structures. The results suggest that only one of the two major orientation states is capable of effector binding. We propose that the different modes of membrane binding may be exploited in structure-based drug design efforts for cancer therapy.
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29
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The power, pitfalls and potential of the nanodisc system for NMR-based studies. Biol Chem 2016; 397:1335-1354. [DOI: 10.1515/hsz-2016-0224] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2016] [Accepted: 07/19/2016] [Indexed: 12/21/2022]
Abstract
Abstract
The choice of a suitable membrane mimicking environment is of fundamental importance for the characterization of structure and function of membrane proteins. In this respect, usage of the lipid bilayer nanodisc technology provides a unique potential for nuclear magnetic resonance (NMR)-based studies. This review summarizes the recent advances in this field, focusing on (i) the strengths of the system, (ii) the bottlenecks that may be faced, and (iii) promising capabilities that may be explored in future studies.
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30
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Mayne CG, Arcario MJ, Mahinthichaichan P, Baylon JL, Vermaas JV, Navidpour L, Wen PC, Thangapandian S, Tajkhorshid E. The cellular membrane as a mediator for small molecule interaction with membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA 2016; 1858:2290-2304. [PMID: 27163493 PMCID: PMC4983535 DOI: 10.1016/j.bbamem.2016.04.016] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 04/26/2016] [Accepted: 04/27/2016] [Indexed: 01/05/2023]
Abstract
The cellular membrane constitutes the first element that encounters a wide variety of molecular species to which a cell might be exposed. Hosting a large number of structurally and functionally diverse proteins associated with this key metabolic compartment, the membrane not only directly controls the traffic of various molecules in and out of the cell, it also participates in such diverse and important processes as signal transduction and chemical processing of incoming molecular species. In this article, we present a number of cases where details of interaction of small molecular species such as drugs with the membrane, which are often experimentally inaccessible, have been studied using advanced molecular simulation techniques. We have selected systems in which partitioning of the small molecule with the membrane constitutes a key step for its final biological function, often binding to and interacting with a protein associated with the membrane. These examples demonstrate that membrane partitioning is not only important for the overall distribution of drugs and other small molecules into different compartments of the body, it may also play a key role in determining the efficiency and the mode of interaction of the drug with its target protein. This article is part of a Special Issue entitled: Biosimulations edited by Ilpo Vattulainen and Tomasz Róg.
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Affiliation(s)
- Christopher G Mayne
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States.
| | - Mark J Arcario
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, United States; College of Medicine, University of Illinois at Urbana-Champaign, United States.
| | - Paween Mahinthichaichan
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Department of Biochemistry, University of Illinois at Urbana-Champaign, United States.
| | - Javier L Baylon
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, United States.
| | - Josh V Vermaas
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, United States.
| | - Latifeh Navidpour
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States.
| | - Po-Chao Wen
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States.
| | - Sundarapandian Thangapandian
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Department of Biochemistry, University of Illinois at Urbana-Champaign, United States.
| | - Emad Tajkhorshid
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, United States; Department of Biochemistry, University of Illinois at Urbana-Champaign, United States; Center for Biophysics and Quantitative Biology, University of Illinois at Urbana-Champaign, United States; College of Medicine, University of Illinois at Urbana-Champaign, United States.
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31
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Abstract
Lipid-modified GTPases in the Ras superfamily that mediate a variety of cell signaling processes were thought to be passively anchored to membranes. However, an increasing number of recent studies are finding that membrane binding of these proteins is hardly a passive process, and it involves the soluble catalytic domain as well as the lipid anchor. The catalytic domain adopts multiple orientations on the membrane surface due to internal fluctuations that are modulated by activation status and mutations. Distinct orientation preferences among small GTPases likely lead to differential signaling outcomes, as downstream effectors can sense different orientations. We review recent studies behind this important conclusion.
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Affiliation(s)
- Priyanka Prakash
- a Department of Integrative Biology and Pharmacology , University of Texas Health Science Center at Houston , Houston , TX , USA
| | - Alemayehu A Gorfe
- a Department of Integrative Biology and Pharmacology , University of Texas Health Science Center at Houston , Houston , TX , USA
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32
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Kovrigina EA, Galiakhmetov AR, Kovrigin EL. The Ras G Domain Lacks the Intrinsic Propensity to Form Dimers. Biophys J 2016; 109:1000-8. [PMID: 26331257 DOI: 10.1016/j.bpj.2015.07.020] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2015] [Revised: 05/27/2015] [Accepted: 07/07/2015] [Indexed: 12/24/2022] Open
Abstract
Ras GTPase is a molecular switch controlling a number of cellular pathways including growth, proliferation, differentiation, and apoptosis. Recent reports indicated that Ras undergoes dimerization at the membrane surface through protein-protein interactions. If firmly established this property of Ras would require profound reassessment of a large amount of published data and modification of the Ras signaling paradigm. One proposed mechanism of dimerization involves formation of salt bridges between the two GTPase domains (G domains) leading to formation of a compact dimer as observed in Ras crystal structures. In this work, we interrogated the intrinsic ability of Ras to self-associate in solution by creating conditions of high local concentration through irreversibly tethering the two G domains together at their unstructured C-terminal tails. We evaluated possible self-association in this inverted tandem conjugate via analysis of the time-domain fluorescence anisotropy and NMR chemical shift perturbations. We did not observe the increased rotational correlation time expected for the G domain dimer. Variation of the ionic strength (to modulate stability of the salt bridges) did not affect the rotational correlation time in the tandem further supporting independent rotational diffusion of two G domains. In a parallel line of experiments to detect and map weak self-association of the G domains, we analyzed NMR chemical shifts perturbations at a number of sites near the crystallographic dimer interface. The nearly complete lack of chemical shift perturbations in the tandem construct supported a simple model with the independent G domains repelled from each other by their overall negative charge. These results lead us to the conclusion that self-association of the G domains cannot be responsible for homodimerization of Ras reported in the literature.
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33
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Raschle T, Lin C, Jungmann R, Shih WM, Wagner G. Controlled Co-reconstitution of Multiple Membrane Proteins in Lipid Bilayer Nanodiscs Using DNA as a Scaffold. ACS Chem Biol 2015; 10:2448-54. [PMID: 26356202 DOI: 10.1021/acschembio.5b00627] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Nanodiscs constitute a tool for the solubilization of membrane proteins in a lipid bilayer, thus offering a near-native membrane environment. Many membrane proteins interact with other membrane proteins; however, the co-reconstitution of multiple membrane proteins in a single nanodisc is a random process that is adversely affected by several factors, including protein aggregation. Here, we present an approach for the controlled co-reconstitution of multiple membrane proteins in a single nanodisc. The temporary attachment of designated oligonucleotides to individual membrane proteins enables the formation of stable, detergent-solubilized membrane protein complexes by base-pairing of complementary oligonucleotide sequences, thus facilitating the insertion of the membrane protein complex into nanodiscs with defined stoichiometry and composition. As a proof of principle, nanodiscs containing a heterodimeric and heterotrimeric membrane protein complex were reconstituted using a fluorescently labeled voltage-gated anion channel (VDAC) as a model system.
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Affiliation(s)
- Thomas Raschle
- Department of Biological Chemistry
and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
| | - Chenxiang Lin
- Department of Biological Chemistry
and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, United States
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
| | - Ralf Jungmann
- Department of Biological Chemistry
and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, United States
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
| | - William M. Shih
- Department of Biological Chemistry
and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
- Department of Cancer Biology, Dana-Farber Cancer Institute, Boston, Massachusetts 02115, United States
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, Massachusetts 02115, United States
| | - Gerhard Wagner
- Department of Biological Chemistry
and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts 02115, United States
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34
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Dibble CC, Cantley LC. Regulation of mTORC1 by PI3K signaling. Trends Cell Biol 2015; 25:545-55. [PMID: 26159692 DOI: 10.1016/j.tcb.2015.06.002] [Citation(s) in RCA: 552] [Impact Index Per Article: 61.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2015] [Revised: 06/08/2015] [Accepted: 06/08/2015] [Indexed: 11/29/2022]
Abstract
The class I phosphoinositide 3-kinase (PI3K)-mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) signaling network directs cellular metabolism and growth. Activation of mTORC1 [composed of mTOR, regulatory-associated protein of mTOR (Raptor), mammalian lethal with SEC13 protein 8(mLST8), 40-kDa proline-rich Akt substrate (PRAS40), and DEP domain-containing mTOR-interacting protein (DEPTOR)] depends on the Ras-related GTPases (Rags) and Ras homolog enriched in brain (Rheb) GTPase and requires signals from amino acids, glucose, oxygen, energy (ATP), and growth factors (including cytokines and hormones such as insulin). Here we discuss the signal transduction mechanisms through which growth factor-responsive PI3K signaling activates mTORC1. We focus on how PI3K-dependent activation of Akt and spatial regulation of the tuberous sclerosis complex (TSC) complex (TSC complex) [composed of TSC1, TSC2, and Tre2-Bub2-Cdc16-1 domain family member 7 (TBC1D7)] switches on Rheb at the lysosome, where mTORC1 is activated. Integration of PI3K- and amino acid-dependent signals upstream of mTORC1 at the lysosome is detailed in a working model. A coherent understanding of the PI3K-mTORC1 network is imperative as its dysregulation has been implicated in diverse pathologies including cancer, diabetes, autism, and aging.
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Affiliation(s)
- Christian C Dibble
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA 02215, USA
| | - Lewis C Cantley
- Meyer Cancer Center, Department of Medicine, Weill Cornell Medical College, New York, NY 10065, USA.
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35
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Malhotra K, Alder NN. Advances in the use of nanoscale bilayers to study membrane protein structure and function. Biotechnol Genet Eng Rev 2015; 30:79-93. [PMID: 25023464 DOI: 10.1080/02648725.2014.921502] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Within the last decade, nanoscale lipid bilayers have emerged as powerful experimental systems in the analysis of membrane proteins (MPs) for both basic and applied research. These discoidal lipid lamellae are stabilized by annuli of specially engineered amphipathic polypeptides (nanodiscs) or polymers (SMALPs/Lipodisqs®). As biomembrane mimetics, they are well suited for the reconstitution of MPs within a controlled lipid environment. Moreover, because they are water-soluble, they are amenable to solution-based biochemical and biophysical experimentation. Hence, due to their solubility, size, stability, and monodispersity, nanoscale lipid bilayers offer technical advantages over more traditional MP analytic approaches such as detergent solubilization and reconstitution into lipid vesicles. In this article, we review some of the most recent advances in the synthesis of polypeptide- and polymer-bound nanoscale lipid bilayers and their application in the study of MP structure and function.
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Affiliation(s)
- Ketan Malhotra
- a Department of Molecular and Cell Biology , University of Connecticut , Storrs , CT 06269 , USA
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36
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Gruschus JM, Byrd RA, Randazzo PA. The importance of seeing surface (effects). Structure 2015; 22:363-5. [PMID: 24607142 DOI: 10.1016/j.str.2014.02.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
In this issue of Structure, Liu and colleagues describe an experimentally rigorous and innovative approach for understanding the role of membranes in the function and regulation of peripheral membrane proteins. This work is the beginning of a new era of experimental work that promises many advances relevant to molecular mechanisms and therapeutic targeting of this important class of proteins.
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Affiliation(s)
- James M Gruschus
- Biochemistry and Biophysics Center, National Heart Lung and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - R Andrew Byrd
- Structural Biophysics Laboratory, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Paul A Randazzo
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
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37
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Oncogenic and RASopathy-associated K-RAS mutations relieve membrane-dependent occlusion of the effector-binding site. Proc Natl Acad Sci U S A 2015; 112:6625-30. [PMID: 25941399 DOI: 10.1073/pnas.1419895112] [Citation(s) in RCA: 171] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
K-RAS4B (Kirsten rat sarcoma viral oncogene homolog 4B) is a prenylated, membrane-associated GTPase protein that is a critical switch for the propagation of growth factor signaling pathways to diverse effector proteins, including rapidly accelerated fibrosarcoma (RAF) kinases and RAS-related protein guanine nucleotide dissociation stimulator (RALGDS) proteins. Gain-of-function KRAS mutations occur frequently in human cancers and predict poor clinical outcome, whereas germ-line mutations are associated with developmental syndromes. However, it is not known how these mutations affect K-RAS association with biological membranes or whether this impacts signal transduction. Here, we used solution NMR studies of K-RAS4B tethered to nanodiscs to investigate lipid bilayer-anchored K-RAS4B and its interactions with effector protein RAS-binding domains (RBDs). Unexpectedly, we found that the effector-binding region of activated K-RAS4B is occluded by interaction with the membrane in one of the NMR-observable, and thus highly populated, conformational states. Binding of the RAF isoform ARAF and RALGDS RBDs induced marked reorientation of K-RAS4B from the occluded state to RBD-specific effector-bound states. Importantly, we found that two Noonan syndrome-associated mutations, K5N and D153V, which do not affect the GTPase cycle, relieve the occluded orientation by directly altering the electrostatics of two membrane interaction surfaces. Similarly, the most frequent KRAS oncogenic mutation G12D also drives K-RAS4B toward an exposed configuration. Further, the D153V and G12D mutations increase the rate of association of ARAF-RBD with lipid bilayer-tethered K-RAS4B. We revealed a mechanism of K-RAS4B autoinhibition by membrane sequestration of its effector-binding site, which can be disrupted by disease-associated mutations. Stabilizing the autoinhibitory interactions between K-RAS4B and the membrane could be an attractive target for anticancer drug discovery.
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38
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Nussinov R, Jang H, Tsai CJ. Oligomerization and nanocluster organization render specificity. Biol Rev Camb Philos Soc 2015; 90:587-98. [PMID: 24917483 PMCID: PMC4263682 DOI: 10.1111/brv.12124] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Revised: 04/30/2014] [Accepted: 05/14/2014] [Indexed: 12/11/2022]
Abstract
Nanoclusters are anchored to membranes, either within them or in the cytoplasm latched onto the cytoskeleton, whose reorganization can regulate their activity. Nanoclusters have been viewed in terms of cooperativity and activation; here we perceive nanocluster organization from a conformational standpoint. This leads us to suggest that while single molecules encode activity, nanoclusters induce specificity, and that this is their main evolutionary aim. Distinct, isoform-specific nanocluster organization can drive the preferred effector (and ligand) interactions and thereby designate signalling pathways. The absence of detailed structural information across the nanocluster, due to size and dynamics, hinders an in-depth grasp of its mechanistic features; however, available data already capture some of the principles and their functional 'raison d'être'. Collectively, clustering lends stability and reduces the likelihood of proteolytic cleavage; it also increases the effective local concentration and enables efficient cooperative activation. However, clustering does not determine the ability of the single molecule to function. Drugs targeting nanoclusters can attenuate activity by hampering cooperativity; however, this may not perturb activation and signalling, which originate from the molecules themselves, and as such, are likely to endure. What then is the major role of nanoclustering? Assuming that single molecules evolved first, with a subsequent increase in cellular complexity and emergence of highly similar isoform variants, evolution faced the threat of signalling promiscuity. We reason that this potential risk was thwarted by oligomerization and clustering; clustering confers higher specificity, and a concomitant extra layer of cellular control. In our Ras example, signalling will be more accurate as a dimer than as a monomer, where its isomer specificity could be compromised.
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Affiliation(s)
- Ruth Nussinov
- Cancer and Inflammation Program, National Cancer Institute, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, MD 21702, USA
- Sackler Inst. of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Hyunbum Jang
- Cancer and Inflammation Program, National Cancer Institute, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, MD 21702, USA
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, National Cancer Institute, Leidos Biomedical Research, Inc., Frederick National Laboratory, Frederick, MD 21702, USA
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39
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Hagn F, Wagner G. Structure refinement and membrane positioning of selectively labeled OmpX in phospholipid nanodiscs. JOURNAL OF BIOMOLECULAR NMR 2015; 61:249-60. [PMID: 25430058 PMCID: PMC4398597 DOI: 10.1007/s10858-014-9883-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 11/20/2014] [Indexed: 05/22/2023]
Abstract
NMR structural studies on membrane proteins are often complicated by their large size, taking into account the contribution of the membrane mimetic. Therefore, classical resonance assignment approaches often fail. The large size of phospholipid nanodiscs, a detergent-free phospholipid bilayer mimetic, prevented their use in high-resolution solution-state NMR spectroscopy so far. We recently introduced smaller nanodiscs that are suitable for NMR structure determination. However, side-chain assignments of a membrane protein in nanodiscs still remain elusive. Here, we utilized a NOE-based approach to assign (stereo-) specifically labeled Ile, Leu, Val and Ala methyl labeled and uniformly (15)N-Phe and (15)N-Tyr labeled OmpX and calculated a refined high-resolution structure. In addition, we were able to obtain residual dipolar couplings (RDCs) of OmpX in nanodiscs using Pf1 phage medium for the induction of weak alignment. Back-calculated NOESY spectra of the obtained NMR structures were compared to experimental NOESYs in order to validate the quality of these structures. We further used NOE information between protonated lipid head groups and side-chain methyls to determine the position of OmpX in the phospholipid bilayer. These data were verified by paramagnetic relaxation enhancement (PRE) experiments obtained with Gd(3+)-modified lipids. Taken together, this study emphasizes the need for the (stereo-) specific labeling of membrane proteins in a highly deuterated background for high-resolution structure determination, particularly in large membrane mimicking systems like phospholipid nanodiscs. Structure validation by NOESY back-calculation will be helpful for the structure determination and validation of membrane proteins where NOE assignment is often difficult. The use of protein to lipid NOEs will be beneficial for the positioning of a membrane protein in the lipid bilayer without the need for preparing multiple protein samples.
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Affiliation(s)
- Franz Hagn
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA, 02115, USA,
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40
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Pleskot R, Cwiklik L, Jungwirth P, Žárský V, Potocký M. Membrane targeting of the yeast exocyst complex. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:1481-9. [PMID: 25838123 DOI: 10.1016/j.bbamem.2015.03.026] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2015] [Revised: 03/20/2015] [Accepted: 03/24/2015] [Indexed: 12/11/2022]
Abstract
The exocytosis is a process of fusion of secretory vesicles with plasma membrane, which plays a prominent role in many crucial cellular processes, e.g. secretion of neurotransmitters, cytokinesis or yeast budding. Prior to the SNARE-mediated fusion, the initial contact of secretory vesicle with the target membrane is mediated by an evolutionary conserved vesicle tethering protein complex, the exocyst. In all eukaryotic cells, the exocyst is composed of eight subunits - Sec5, Sec6, Sec8, Sec10, Sec15, Exo84 and two membrane-targeting landmark subunits Sec3 and Exo70, which have been described to directly interact with phosphatidylinositol (4,5)-bisphosphate (PIP2) of the plasma membrane. In this work, we utilized coarse-grained molecular dynamics simulations to elucidate structural details of the interaction of yeast Sec3p and Exo70p with lipid bilayers containing PIP2. We found that PIP2 is coordinated by the positively charged pocket of N-terminal part of Sec3p, which folds into unique Pleckstrin homology domain. Conversely, Exo70p interacts with the lipid bilayer by several binding sites distributed along the structure of this exocyst subunit. Moreover, we observed that the interaction of Exo70p with the membrane causes clustering of PIP2 in the adjacent leaflet. We further revealed that PIP2 is required for the correct positioning of small GTPase Rho1p, a direct Sec3p interactor, prior to the formation of the functional Rho1p-exocyst-membrane assembly. Our results show the critical importance of the plasma membrane pool of PIP2 for the exocyst function and suggest that specific interaction with acidic phospholipids represents an ancestral mechanism for the exocyst regulation.
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Affiliation(s)
- Roman Pleskot
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 165 02 Prague, Czech Republic; Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague, Czech Republic.
| | - Lukasz Cwiklik
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague, Czech Republic; J. Heyrovsky Institute of Physical Chemistry, Academy of Sciences of the Czech Republic, 182 23 Prague, Czech Republic
| | - Pavel Jungwirth
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, 166 10 Prague, Czech Republic; Department of Physics, Tampere University of Technology, FI-33101 Tampere, Finland
| | - Viktor Žárský
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 165 02 Prague, Czech Republic; Department of Experimental Plant Biology, Charles University in Prague, 128 44 Prague, Czech Republic
| | - Martin Potocký
- Institute of Experimental Botany, Academy of Sciences of the Czech Republic, 165 02 Prague, Czech Republic.
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41
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Smith MJ, Marshall CB, Theillet FX, Binolfi A, Selenko P, Ikura M. Real-time NMR monitoring of biological activities in complex physiological environments. Curr Opin Struct Biol 2015; 32:39-47. [PMID: 25727665 DOI: 10.1016/j.sbi.2015.02.003] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/03/2015] [Accepted: 02/05/2015] [Indexed: 11/19/2022]
Abstract
Biological reactions occur in a highly organized spatiotemporal context and with kinetics that are modulated by multiple environmental factors. To integrate these variables in our experimental investigations of 'native' biological activities, we require quantitative tools for time-resolved in situ analyses in physiologically relevant settings. Here, we outline the use of high-resolution NMR spectroscopy to directly observe biological reactions in complex environments and in real-time. Specifically, we discuss how real-time NMR (RT-NMR) methods have delineated insights into metabolic processes, post-translational protein modifications, activities of cellular GTPases and their regulators, as well as of protein folding events.
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Affiliation(s)
- Matthew J Smith
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Christopher B Marshall
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Toronto, Ontario, Canada
| | - Francois-Xavier Theillet
- In-Cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Berlin, Germany
| | - Andres Binolfi
- In-Cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Berlin, Germany
| | - Philipp Selenko
- In-Cell NMR Laboratory, Department of NMR-supported Structural Biology, Leibniz Institute of Molecular Pharmacology (FMP Berlin), Berlin, Germany.
| | - Mitsuhiko Ikura
- Campbell Family Cancer Research Institute, Ontario Cancer Institute, Toronto, Ontario, Canada; Department of Medical Biophysics, University of Toronto, Toronto, Ontario, Canada.
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42
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Scheidelaar S, Koorengevel MC, Pardo JD, Meeldijk JD, Breukink E, Killian JA. Molecular model for the solubilization of membranes into nanodisks by styrene maleic Acid copolymers. Biophys J 2015; 108:279-90. [PMID: 25606677 PMCID: PMC4302193 DOI: 10.1016/j.bpj.2014.11.3464] [Citation(s) in RCA: 130] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/20/2014] [Accepted: 11/24/2014] [Indexed: 01/11/2023] Open
Abstract
A recent discovery in membrane research is the ability of styrene-maleic acid (SMA) copolymers to solubilize membranes in the form of nanodisks allowing extraction and purification of membrane proteins from their native environment in a single detergent-free step. This has important implications for membrane research because it allows isolation as well as characterization of proteins and lipids in a near-native environment. Here, we aimed to unravel the molecular mode of action of SMA copolymers by performing systematic studies using model membranes of varying compositions and employing complementary biophysical approaches. We found that the SMA copolymer is a highly efficient membrane-solubilizing agent and that lipid bilayer properties such as fluidity, thickness, lateral pressure profile, and charge density all play distinct roles in the kinetics of solubilization. More specifically, relatively thin membranes, decreased lateral chain pressure, low charge density at the membrane surface, and increased salt concentration promote the speed and yield of vesicle solubilization. Experiments using a native membrane lipid extract showed that the SMA copolymer does not discriminate between different lipids and thus retains the native lipid composition in the solubilized particles. A model is proposed for the mode of action of SMA copolymers in which membrane solubilization is mainly driven by the hydrophobic effect and is further favored by physical properties of the polymer such as its relatively small cross-sectional area and rigid pendant groups. These results may be helpful for development of novel applications for this new type of solubilizing agent, and for optimization of the SMA technology for solubilization of the wide variety of cell membranes found in nature.
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Affiliation(s)
- Stefan Scheidelaar
- Membrane Biochemistry & Biophysics, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan, Utrecht, The Netherlands.
| | - Martijn C Koorengevel
- Membrane Biochemistry & Biophysics, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan, Utrecht, The Netherlands
| | - Juan Dominguez Pardo
- Membrane Biochemistry & Biophysics, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan, Utrecht, The Netherlands
| | - Johannes D Meeldijk
- Electron Microscopy Utrecht, Debye Institute of Nanomaterials Science, Faculty of Science, Utrecht University, Padualaan, Utrecht, The Netherlands
| | - Eefjan Breukink
- Membrane Biochemistry & Biophysics, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan, Utrecht, The Netherlands
| | - J Antoinette Killian
- Membrane Biochemistry & Biophysics, Bijvoet Center for Biomolecular Research, Department of Chemistry, Faculty of Science, Utrecht University, Padualaan, Utrecht, The Netherlands
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43
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Ambidextrous binding of cell and membrane bilayers by soluble matrix metalloproteinase-12. Nat Commun 2014; 5:5552. [PMID: 25412686 DOI: 10.1038/ncomms6552] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2014] [Accepted: 10/10/2014] [Indexed: 01/15/2023] Open
Abstract
Matrix metalloproteinases (MMPs) regulate tissue remodelling, inflammation and disease progression. Some soluble MMPs are inexplicably active near cell surfaces. Here we demonstrate the binding of MMP-12 directly to bilayers and cellular membranes using paramagnetic NMR and fluorescence. Opposing sides of the catalytic domain engage spin-labelled membrane mimics. Loops project from the β-sheet interface to contact the phospholipid bilayer with basic and hydrophobic residues. The distal membrane interface comprises loops on the other side of the catalytic cleft. Both interfaces mediate MMP-12 association with vesicles and cell membranes. MMP-12 binds plasma membranes and is internalized to hydrophobic perinuclear features, the nuclear membrane and inside the nucleus within minutes. While binding of TIMP-2 to MMP-12 hinders membrane interactions beside the active site, TIMP-2-inhibited MMP-12 binds vesicles and cells, suggesting compensatory rotation of its membrane approaches. MMP-12 association with diverse cell membranes may target its activities to modulate innate immune responses and inflammation.
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44
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Sugiki T, Fujiwara T, Kojima C. Latest approaches for efficient protein production in drug discovery. Expert Opin Drug Discov 2014; 9:1189-204. [PMID: 25046062 DOI: 10.1517/17460441.2014.941801] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Pharmaceutical research looks to discover and develop new compounds which influence the function of disease-associated proteins or respective protein-protein interactions. Various scientific methods are available to discover those compounds, such as high-throughput screening of a library comprising chemical or natural compounds and computational rational drug design. The goal of these methods is to identify the seed compounds of future pharmaceuticals through the use of these technologies and laborious experiments. For every drug discovery effort made, the possession of accurate functional and structural information of the disease-associated proteins helps to assist drug development. Therefore, the investigation of the tertiary structure of disease-associated proteins and respective protein-protein interactions at the atomic level are of crucial importance for successful drug discovery. AREAS COVERED In this review article, the authors broadly outline current techniques utilized for recombinant protein production. In particular, the authors focus on bacterial expression systems using Escherichia coli as the living bioreactor. EXPERT OPINION The recently developed pCold-glutathione S-transferase (GST) system is one of the best systems for soluble protein expression in E. coli. Where the pCold-GST system does not succeed, it is preferable to change the host from E. coli to higher organisms such as yeast expression systems like Pichia pastoris and Kluyveromyces lactis. The selection of an appropriate expression system for each desired protein and the optimization of experimental conditions significantly contribute toward the successful outcome of any drug discovery study.
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Affiliation(s)
- Toshihiko Sugiki
- Osaka University, Institute for Protein Research , 3-2, Yamadaoka, Suita, Osaka 565-0871 , Japan
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45
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Recent progress in the study of the Rheb family GTPases. Cell Signal 2014; 26:1950-7. [PMID: 24863881 DOI: 10.1016/j.cellsig.2014.05.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Accepted: 05/15/2014] [Indexed: 11/20/2022]
Abstract
In this review we highlight recent progress in the study of Rheb family GTPases. Structural studies using X-ray crystallography and NMR have given us insight into unique features of this GTPase. Combined with mutagenesis studies, these works have expanded our understanding of residues that affect Rheb GTP/GDP bound ratios, effector protein interactions, and stimulation of mTORC1 signaling. Analysis of cancer genome databases has revealed that several human carcinomas contain activating mutations of the protein. Rheb's role in activating mTORC1 signaling at the lysosome in response to stimuli has been further elucidated. Rheb has also been suggested to play roles in other cellular pathways including mitophagy and peroxisomal ROS response. A number of studies in mice have demonstrated the importance of Rheb in development, as well as in a variety of functions including cardiac protection and myelination. We conclude with a discussion of future prospects in the study of Rheb family GTPases.
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Giusti F, Rieger J, Catoire LJ, Qian S, Calabrese AN, Watkinson TG, Casiraghi M, Radford SE, Ashcroft AE, Popot JL. Synthesis, characterization and applications of a perdeuterated amphipol. J Membr Biol 2014; 247:909-24. [PMID: 24652511 DOI: 10.1007/s00232-014-9656-x] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 03/07/2014] [Indexed: 12/13/2022]
Abstract
Amphipols are short amphipathic polymers that can substitute for detergents at the hydrophobic surface of membrane proteins (MPs), keeping them soluble in the absence of detergents while stabilizing them. The most widely used amphipol, known as A8-35, is comprised of a polyacrylic acid (PAA) main chain grafted with octylamine and isopropylamine. Among its many applications, A8-35 has proven particularly useful for solution-state NMR studies of MPs, for which it can be desirable to eliminate signals originating from the protons of the surfactant. In the present work, we describe the synthesis and properties of perdeuterated A8-35 (perDAPol). Perdeuterated PAA was obtained by radical polymerization of deuterated acrylic acid. It was subsequently grafted with deuterated amines, yielding perDAPol. The number-average molar mass of hydrogenated and perDAPol, ~4 and ~5 kDa, respectively, was deduced from that of their PAA precursors, determined by size exclusion chromatography in tetrahydrofuran following permethylation. Electrospray ionization-ion mobility spectrometry-mass spectrometry measurements show the molar mass and distribution of the two APols to be very similar. Upon neutron scattering, the contrast match point of perDAPol is found to be ~120% D2O. In (1)H-(1)H nuclear overhauser effect NMR spectra, its contribution is reduced to ~6% of that of hydrogenated A8-35, making it suitable for extended uses in NMR spectroscopy. PerDAPol ought to also be of use for inelastic neutron scattering studies of the dynamics of APol-trapped MPs, as well as small-angle neutron scattering and analytical ultracentrifugation.
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Affiliation(s)
- Fabrice Giusti
- Laboratoire de Physico-Chimie Moléculaire des Membranes Biologiques, UMR 7099, Institut de Biologie Physico-Chimique (FRC 550), Centre National de la Recherche Scientifique and Université Paris-7, 13 rue Pierre et Marie Curie, 75005, Paris, France
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Prakash P, Gorfe AA. Overview of simulation studies on the enzymatic activity and conformational dynamics of the GTPase Ras. MOLECULAR SIMULATION 2014; 40:839-847. [PMID: 26491216 DOI: 10.1080/08927022.2014.895000] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Over the last 40 years, we have learnt a great deal about the Ras onco-proteins. These intracellular molecular switches are essential for the function of a variety of physiological processes, including signal transduction cascades responsible for cell growth and proliferation. Molecular simulations and free energy calculations have played an essential role in elucidating the conformational dynamics and energetics underlying the GTP hydrolysis reaction catalysed by Ras. Here we present an overview of the main lessons from molecular simulations on the GTPase reaction and conformational dynamics of this important anti-cancer drug target. In the first part, we summarise insights from quantum mechanical and combined quantum mechanical/molecular mechanical simulations as well as other free energy methods and highlight consensus viewpoints as well as remaining controversies. The second part provides a very brief overview of new insights emerging from large-scale molecular dynamics simulations. We conclude with a perspective regarding future studies of Ras where computational approaches will likely play an active role.
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Affiliation(s)
- Priyanka Prakash
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, 6431 Fannin St, Houston, TX 77030, USA
| | - Alemayehu A Gorfe
- Department of Integrative Biology and Pharmacology, University of Texas Medical School at Houston, 6431 Fannin St, Houston, TX 77030, USA
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Nomura K, Harada E, Sugase K, Shimamoto K. Solid-state NMR spectra of lipid-anchored proteins under magic angle spinning. J Phys Chem B 2014; 118:2405-13. [PMID: 24517164 DOI: 10.1021/jp4124106] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Solid-state NMR is a promising tool for elucidating membrane-related biological phenomena. We achieved the measurement of high-resolution solid-state NMR spectra for a lipid-anchored protein embedded in lipid bilayers under magic angle spinning (MAS). To date, solid-state NMR measurements of lipid-anchored proteins have not been accomplished due to the difficulty in supplying sufficient amount of stable isotope labeled samples in the overexpression of lipid-anchored proteins requiring complex posttranslational modification. We designed a pseudo lipid-anchored protein in which the protein component was expressed in E. coli and attached to a chemically synthesized lipid-anchor mimic. Using two types of membranes, liposomes and bicelles, we demonstrated different types of insertion procedures for lipid-anchored protein into membranes. In the liposome sample, we were able to observe the cross-polarization and the (13)C-(13)C chemical shift correlation spectra under MAS, indicating that the liposome sample can be used to analyze molecular interactions using dipolar-based NMR experiments. In contrast, the bicelle sample showed sufficient quality of spectra through scalar-based experiments. The relaxation times and protein-membrane interaction were capable of being analyzed in the bicelle sample. These results demonstrated the applicability of two types of sample system to elucidate the roles of lipid-anchors in regulating diverse biological phenomena.
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Affiliation(s)
- Kaoru Nomura
- Bioorganic Research Institute, Suntory Foundation for Life Sciences , 1-1-1 Wakayamadai, Shimamoto-Cho, Mishima-Gun, Osaka 618-8503, Japan
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Guzmán C, Šolman M, Ligabue A, Blaževitš O, Andrade DM, Reymond L, Eggeling C, Abankwa D. The efficacy of Raf kinase recruitment to the GTPase H-ras depends on H-ras membrane conformer-specific nanoclustering. J Biol Chem 2014; 289:9519-33. [PMID: 24569991 DOI: 10.1074/jbc.m113.537001] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Solution structures and biochemical data have provided a wealth of mechanistic insight into Ras GTPases. However, information on how much the membrane organization of these lipid-modified proteins impacts on their signaling is still scarce. Ras proteins are organized into membrane nanoclusters, which are necessary for Ras-MAPK signaling. Using quantitative conventional and super-resolution fluorescence methods, as well as mathematical modeling, we investigated nanoclustering of H-ras helix α4 and hypervariable region mutants that have different bona fide conformations on the membrane. By following the emergence of conformer-specific nanoclusters in the plasma membrane of mammalian cells, we found that conformers impart distinct nanoclustering responses depending on the cytoplasmic levels of the nanocluster scaffold galectin-1. Computational modeling revealed that complexes containing H-ras conformers and galectin-1 affect both the number and lifetime of nanoclusters and thus determine the specific Raf effector recruitment. Our results show that mutations in Ras can affect its nanoclustering response and thus allosterically effector recruitment and downstream signaling. We postulate that cancer- and developmental disease-linked mutations that are associated with the Ras membrane conformation may exhibit so far unrecognized Ras nanoclustering and therefore signaling alterations.
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Affiliation(s)
- Camilo Guzmán
- From the Turku Centre for Biotechnology, Åbo Akademi University, Tykistökatu 6B, 20520 Turku, Finland
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Abstract
mTORC1 (mammalian target of rampamycin complex 1) is a highly conserved protein complex regulating cell growth and metabolism via its kinase mTOR (mammalian target of rapamycin). The activity of mTOR is under the control of various GTPases, of which Rheb and the Rags play a central role. The presence of amino acids is a strict requirement for mTORC1 activity. The heterodimeric Rag GTPases localize mTORC1 to lysosomes by their amino-acid-dependent interaction with the lysosomal Ragulator complex. Rheb is also thought to reside on lysosomes to activate mTORC1. Rheb is responsive to growth factors, but, in conjunction with PLD1 (phospholipase D1), is also an integral part of the machinery that stimulates mTORC1 in response to amino acids. In the present article, we provide a brief overview of novel mechanisms by which amino acids affect the function of Rags. On the basis of existing literature, we postulate that Rheb is activated at the Golgi from where it will travel to lysosomes. Maturation of endosomes into lysosomes may be required to assure a continuous supply of GTP-bound Rheb for mTORC1 activation, which may help to drive the maturation process.
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