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Arora N, Liang H, Yao W, Ying H, Liu J, Zhou Y. Lysophosphatidylcholine acyltransferase 1 suppresses nanoclustering and function of KRAS. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.30.596653. [PMID: 38853864 PMCID: PMC11160780 DOI: 10.1101/2024.05.30.596653] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2024]
Abstract
KRAS is frequently mutated in cancer, contributing to 20% of all human cancer especially pancreatic, colorectal and lung cancer. Signaling of the constitutively active KRAS oncogenic mutants is mostly compartmentalized to proteolipid nanoclusters on the plasma membrane (PM). Signaling nanoclusters of many KRAS mutants selectively enrich phosphatidylserine (PS) lipids with unsaturated sn-2 acyl chains, but not the fully saturated PS species. Thus, remodeling PS acyl chains may suppress KRAS oncogenesis. Lysophosphatidylcholine acyltransferases (LPCATs) remodel sn-2 acyl chains of phospholipids, with LPCAT1 preferentially generating the fully saturated lipids. Here, we show that stable expression of LPCAT1 depletes major PS species with unsaturated sn-2 chains while decreasing minor phosphatidylcholine (PC) species with the corresponding acyl chains. LPCAT1 expression more effectively disrupts the nanoclustering of oncogenic GFP-KRASG12V, which is restored by acute addback of exogenous unsaturated PS. LPCAT1 expression compromises signaling and oncogenic activities of the KRAS-dependent pancreatic tumor lines. LPCAT1 expression sensitizes human pancreatic tumor MiaPaCa-2 cells to KRASG12C specific inhibitor, Sotorasib. Statistical analyses of patient data further reveal that pancreatic cancer patients with KRAS mutations express less LPCAT1. Higher LPCAT1 expression also improves survival probability of pancreatic and lung adenocarcinoma patients with KRAS mutations. Thus, PS acyl chain remodeling selectively suppresses KRAS oncogenesis.
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Affiliation(s)
- Neha Arora
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
| | - Hong Liang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
| | - Wantong Yao
- Department of Translational Molecular Pathology, Division of Pathology-Lab Medicine Div, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Haoqiang Ying
- Department of Molecular and Cellular Oncology, Division of Basic Science Research, The University of Texas MD Anderson Cancer Center, Houston, Texas, USA
| | - Junchen Liu
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
| | - Yong Zhou
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, Texas, USA
- Program of Biochemistry and Cell Biology, Graduate School of Biological Sciences, M. D. Anderson Cancer Center and University of Texas Health Science Center, Houston, Texas, USA
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Kashnik AS, Baranov DS, Dzuba SA. Spatial Arrangement of the Drug Ibuprofen in a Model Membrane in the Presence of Lipid Rafts. J Phys Chem B 2024; 128:3652-3661. [PMID: 38576273 DOI: 10.1021/acs.jpcb.4c01507] [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: 04/06/2024]
Abstract
Many pharmaceutical drugs are known to interact with lipid membranes through nonspecific molecular interactions, which affect their therapeutic effect. Ibuprofen is a nonsteroidal anti-inflammatory drug (NSAID) and one of the most commonly prescribed. In the presence of cholesterol, lipid bilayers can separate into nanoscale liquid-disordered and liquid-ordered structures, the latter known as lipid rafts. Here, we study spin-labeled ibuprofen (ibuprofen-SL) in the model membrane consisting of 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC), 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC), and cholesterol in the molar ratio of (0.5-0.5xchol)/(0.5-0.5xchol)/xchol. Electron paramagnetic resonance (EPR) spectroscopy is employed, along with its pulsed version of double electron-electron resonance (DEER, also known as PELDOR). The data obtained indicate lateral lipid-mediated clustering of ibuprofen-SL molecules with a local surface density noticeably larger than that expected for random lateral distribution. In the absence of cholesterol, the data can be interpreted as indicating alternating clustering in two opposing leaflets of the bilayer. In the presence of cholesterol, for xchol ≥ 20 mol %, the results show that ibuprofen-SL molecules have a quasi-regular lateral distribution, with a "superlattice" parameter of ∼3.0 nm. This regularity can be explained by the entrapment of ibuprofen-SL molecules by lipid rafts known to exist in this system with the additional assumption that lipid rafts have a nanoscale substructure.
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Affiliation(s)
- Anna S Kashnik
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Denis S Baranov
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Sergei A Dzuba
- Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
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Alkafaas SS, Abdallah AM, Hassan MH, Hussien AM, Elkafas SS, Loutfy SA, Mikhail A, Murad OG, Elsalahaty MI, Hessien M, Elshazli RM, Alsaeed FA, Ahmed AE, Kamal HK, Hafez W, El-Saadony MT, El-Tarabily KA, Ghosh S. Molecular docking as a tool for the discovery of novel insight about the role of acid sphingomyelinase inhibitors in SARS- CoV-2 infectivity. BMC Public Health 2024; 24:395. [PMID: 38321448 PMCID: PMC10848368 DOI: 10.1186/s12889-024-17747-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Accepted: 01/11/2024] [Indexed: 02/08/2024] Open
Abstract
Recently, COVID-19, caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and its variants, caused > 6 million deaths. Symptoms included respiratory strain and complications, leading to severe pneumonia. SARS-CoV-2 attaches to the ACE-2 receptor of the host cell membrane to enter. Targeting the SARS-CoV-2 entry may effectively inhibit infection. Acid sphingomyelinase (ASMase) is a lysosomal protein that catalyzes the conversion of sphingolipid (sphingomyelin) to ceramide. Ceramide molecules aggregate/assemble on the plasma membrane to form "platforms" that facilitate the viral intake into the cell. Impairing the ASMase activity will eventually disrupt viral entry into the cell. In this review, we identified the metabolism of sphingolipids, sphingolipids' role in cell signal transduction cascades, and viral infection mechanisms. Also, we outlined ASMase structure and underlying mechanisms inhibiting viral entry 40 with the aid of inhibitors of acid sphingomyelinase (FIASMAs). In silico molecular docking analyses of FIASMAs with inhibitors revealed that dilazep (S = - 12.58 kcal/mol), emetine (S = - 11.65 kcal/mol), pimozide (S = - 11.29 kcal/mol), carvedilol (S = - 11.28 kcal/mol), mebeverine (S = - 11.14 kcal/mol), cepharanthine (S = - 11.06 kcal/mol), hydroxyzin (S = - 10.96 kcal/mol), astemizole (S = - 10.81 kcal/mol), sertindole (S = - 10.55 kcal/mol), and bepridil (S = - 10.47 kcal/mol) have higher inhibition activity than the candidate drug amiodarone (S = - 10.43 kcal/mol), making them better options for inhibition.
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Affiliation(s)
- Samar Sami Alkafaas
- Molecular Cell Biology Unit, Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt.
| | - Abanoub Mosaad Abdallah
- Narcotic Research Department, National Center for Social and Criminological Research (NCSCR), Giza, 11561, Egypt
| | - Mai H Hassan
- Molecular Cell Biology Unit, Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Aya Misbah Hussien
- Biotechnology department at Institute of Graduate Studies and Research, Alexandria University, Alexandria, Egypt
| | - Sara Samy Elkafas
- Production Engineering and Mechanical Design Department, Faculty of Engineering, Menofia University, Menofia, Egypt
- Faculty of Control System and Robotics, ITMO University, Saint-Petersburg, 197101, Russia
| | - Samah A Loutfy
- Virology and Immunology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
- Nanotechnology Research Center, British University, Cairo, Egypt
| | - Abanoub Mikhail
- Department of Physics, Faculty of Science, Minia University, Minia, Egypt
- Faculty of Physics, ITMO University, Saint Petersburg, Russia
| | - Omnia G Murad
- Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Mohamed I Elsalahaty
- Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Mohamed Hessien
- Molecular Cell Biology Unit, Division of Biochemistry, Department of Chemistry, Faculty of Science, Tanta University, Tanta, 31527, Egypt
| | - Rami M Elshazli
- Biochemistry and Molecular Genetics Unit, Department of Basic Sciences, Faculty of Physical Therapy, Horus University - Egypt, New Damietta, 34517, Egypt
| | - Fatimah A Alsaeed
- Department of Biology, College of Science, King Khalid University, Muhayl, Saudi Arabia
| | - Ahmed Ezzat Ahmed
- Biology Department, College of Science, King Khalid University, Abha, 61413, Saudi Arabia
| | - Hani K Kamal
- Anatomy and Histology, Faculty of Pharmacy, King Abdulaziz University, Jeddah, 21589, Saudi Arabia
| | - Wael Hafez
- NMC Royal Hospital, 16Th Street, 35233, Khalifa City, Abu Dhabi, United Arab Emirates
- Medical Research Division, Department of Internal Medicine, The National Research Centre, 12622, 33 El Buhouth St, Ad Doqi, Dokki, Cairo Governorate, Egypt
| | - Mohamed T El-Saadony
- Department of Agricultural Microbiology, Faculty of Agriculture, Zagazig University, Zagazig, 44511, Egypt
| | - Khaled A El-Tarabily
- Department of Biology, College of Science, United Arab Emirates University, Al-Ain, 15551, United Arab Emirates
| | - Soumya Ghosh
- Department of Genetics, Faculty of Natural and Agricultural Sciences, University of the Free State, Bloemfontein, 9301, South Africa
- Natural & Medical Science Research Center, University of Nizwa, Nizwa, Oman
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Kashnik AS, Selyutina OY, Baranov DS, Polyakov NE, Dzuba SA. Localization of the ibuprofen molecule in model lipid membranes revealed by spin-label-enhanced NMR relaxation. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184215. [PMID: 37633627 DOI: 10.1016/j.bbamem.2023.184215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2023] [Revised: 08/10/2023] [Accepted: 08/17/2023] [Indexed: 08/28/2023]
Abstract
Non-steroidal anti-inflammatory drugs (NSAIDs) have antipyretic, anti-inflammatory and analgesic effects, and can be used in the treatment of various diseases. These drugs have also a number of side effects, which may be related to their interaction with lipid membranes. In this study, we use the spin-labeled NSAID ibuprofen (ibuprofen-SL) as a relaxation enhancer to study its interaction with model lipid membranes employing liquid-state 1H NMR at 500 MHz. The high magnetic moment of unpaired electron in the spin label made it possible to reduce the concentration of the studied drug in the membrane to tenths of a mole percent. As model membranes, unilamellar POPC liposomes and bicelles consisting of a 2:1 mixture of DHPC:DMPC or DHPC:POPC lipids were used. An increase in the rate of proton spin-lattice relaxation, T1-1, selectively detected for protons at different positions in the lipid molecule, showed that ibuprofen-SL is localized in the hydrophobic part of the lipid bilayer. As the concentration of ibuprofen-SL increases to 0.5 mol%, the distribution of positions of ibuprofen-SL across the bilayer becomes wider. In the presence of 20 mol% of cholesterol, ibuprofen-SL is displaced from the core of the membrane to a region closer to the head group of the bilayer. This displacement was also confirmed by the NMR NOESY experiment conducted with unlabeled ibuprofen. For bilayers containing unsaturated POPC lipids, the distribution of ibuprofen positions across the bilayer becomes narrower compared to the presence of saturated DMPC lipids.
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Affiliation(s)
- Anna S Kashnik
- Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Olga Yu Selyutina
- Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Denis S Baranov
- Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Nikolay E Polyakov
- Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia
| | - Sergei A Dzuba
- Voevodsky Institute of Chemical Kinetics and Combustion, Russian Academy of Sciences, Novosibirsk 630090, Russia; Novosibirsk State University, Novosibirsk 630090, Russia.
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5
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Zhou Y, Hancock JF. RAS nanoclusters are cell surface transducers that convert extracellular stimuli to intracellular signalling. FEBS Lett 2023; 597:892-908. [PMID: 36595205 PMCID: PMC10919257 DOI: 10.1002/1873-3468.14569] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Revised: 12/05/2022] [Accepted: 12/12/2022] [Indexed: 01/04/2023]
Abstract
Mutations of rat sarcoma virus (RAS) oncogenes (HRAS, KRAS and NRAS) can contribute to the development of cancers and genetic disorders (RASopathies). The spatiotemporal organization of RAS is an important property that warrants further investigation. In order to function, wild-type or oncogenic mutants of RAS must be localized to the inner leaflet of the plasma membrane (PM), which is driven by interactions between their C-terminal membrane-anchoring domains and PM lipids. The isoform-specific RAS-lipid interactions promote the formation of nanoclusters on the PM. As main sites for effector recruitment, these nanoclusters are biologically important. Since the spatial distribution of lipids is sensitive to changing environments, such as mechanical and electrical perturbations, RAS nanoclusters act as transducers to convert external stimuli to intracellular mitogenic signalling. As such, effective inhibition of RAS oncogenesis requires consideration of the complex interplay between RAS nanoclusters and various cell surface and extracellular stimuli. In this review, we discuss in detail how, by sorting specific lipids in the PM, RAS nanoclusters act as transducers to convert external stimuli into intracellular signalling.
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Affiliation(s)
- Yong Zhou
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, McGovern Medical School, TX, USA
- Graduate School of Biomedical Sciences, University of Texas MD Anderson Cancer Center and University of Texas Health Science Center, TX, USA
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, McGovern Medical School, TX, USA
- Graduate School of Biomedical Sciences, University of Texas MD Anderson Cancer Center and University of Texas Health Science Center, TX, USA
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6
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Remodeling of the Plasma Membrane by Surface-Bound Protein Monomers and Oligomers: The Critical Role of Intrinsically Disordered Regions. J Membr Biol 2022; 255:651-663. [PMID: 35930019 PMCID: PMC9718270 DOI: 10.1007/s00232-022-00256-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 07/07/2022] [Indexed: 12/24/2022]
Abstract
The plasma membrane (PM) of cells is a dynamic structure whose morphology and composition is in constant flux. PM morphologic changes are particularly relevant for the assembly and disassembly of signaling platforms involving surface-bound signaling proteins, as well as for many other mechanochemical processes that occur at the PM surface. Surface-bound membrane proteins (SBMP) require efficient association with the PM for their function, which is often achieved by the coordinated interactions of intrinsically disordered regions (IDRs) and globular domains with membrane lipids. This review focuses on the role of IDR-containing SBMPs in remodeling the composition and curvature of the PM. The ability of IDR-bearing SBMPs to remodel the Gaussian and mean curvature energies of the PM is intimately linked to their ability to sort subsets of phospholipids into nanoclusters. We therefore discuss how IDRs of many SBMPs encode lipid-binding specificity or facilitate cluster formation, both of which increase their membrane remodeling capacity, and how SBMP oligomers alter membrane shape by monolayer surface area expansion and molecular crowding.
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Fricke N, Raghunathan K, Tiwari A, Stefanski KM, Balakrishnan M, Waterson AG, Capone R, Huang H, Sanders CR, Bauer JA, Kenworthy AK. High-Content Imaging Platform to Discover Chemical Modulators of Plasma Membrane Rafts. ACS CENTRAL SCIENCE 2022; 8:370-378. [PMID: 35355811 PMCID: PMC8961798 DOI: 10.1021/acscentsci.1c01058] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Indexed: 05/05/2023]
Abstract
Plasma membrane organization profoundly impacts cellular functionality. A well-known mechanism underlying this organization is through nanoscopic clustering of distinct lipids and proteins in membrane rafts. Despite their physiological importance, rafts remain a difficult-to-study aspect of membrane organization, in part because of the paucity of chemical tools to experimentally modulate their properties. Methods to selectively target rafts for therapeutic purposes are also currently lacking. To tackle these problems, we developed a high-throughput screen and an accompanying image analysis pipeline to identify small molecules that enhance or inhibit raft formation. Cell-derived giant plasma membrane vesicles were used as the experimental platform. A proof-of-principle screen using a bioactive lipid library demonstrates that this method is robust and capable of validating established raft modulators including C6- and C8-ceramide, miltefosine, and epigallocatechin gallate as well as identifying new ones. The platform we describe here represents a powerful tool to discover new chemical approaches to manipulate rafts and their components.
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Affiliation(s)
- Nico Fricke
- Department
of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Krishnan Raghunathan
- Department
of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Ajit Tiwari
- Department
of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Katherine M. Stefanski
- Department
of Biochemistry, Vanderbilt School of Medicine, Nashville, Tennessee 37240, United States
| | - Muthuraj Balakrishnan
- Center
for Membrane and Cell Physiology and Department of Molecular Physiology
and Biological Physics, University of Virginia
School of Medicine, Charlottesville, Virginia 22903, United States
| | - Alex G. Waterson
- Department
of Pharmacology, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Ricardo Capone
- Department
of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Hui Huang
- Department
of Biochemistry, Vanderbilt School of Medicine, Nashville, Tennessee 37240, United States
| | - Charles R. Sanders
- Department
of Biochemistry, Vanderbilt School of Medicine, Nashville, Tennessee 37240, United States
| | - Joshua A. Bauer
- Department
of Biochemistry, Vanderbilt School of Medicine, Nashville, Tennessee 37240, United States
- Vanderbilt
Institute of Chemical Biology, High-Throughput Screening Facility, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
| | - Anne K. Kenworthy
- Department
of Molecular Physiology and Biophysics, Vanderbilt School of Medicine, Nashville, Tennessee 37232, United States
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Raphael RM. Outer Hair Cell Electromechanics as a Problem in Soft Matter Physics: Prestin, the Membrane and the Cytoskeleton. Hear Res 2021; 423:108426. [DOI: 10.1016/j.heares.2021.108426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 12/17/2021] [Accepted: 12/23/2021] [Indexed: 11/28/2022]
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Zhou Y, Gorfe AA, Hancock JF. RAS Nanoclusters Selectively Sort Distinct Lipid Headgroups and Acyl Chains. Front Mol Biosci 2021; 8:686338. [PMID: 34222339 PMCID: PMC8245699 DOI: 10.3389/fmolb.2021.686338] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 05/13/2021] [Indexed: 12/12/2022] Open
Abstract
RAS proteins are lipid-anchored small GTPases that switch between the GTP-bound active and GDP-bound inactive states. RAS isoforms, including HRAS, NRAS and splice variants KRAS4A and KRAS4B, are some of the most frequently mutated proteins in cancer. In particular, constitutively active mutants of KRAS comprise ∼80% of all RAS oncogenic mutations and are found in 98% of pancreatic, 45% of colorectal and 31% of lung tumors. Plasma membrane (PM) is the primary location of RAS signaling in biology and pathology. Thus, a better understanding of how RAS proteins localize to and distribute on the PM is critical to better comprehend RAS biology and to develop new strategies to treat RAS pathology. In this review, we discuss recent findings on how RAS proteins sort lipids as they undergo macromolecular assembly on the PM. We also discuss how RAS/lipid nanoclusters serve as signaling platforms for the efficient recruitment of effectors and signal transduction, and how perturbing the PM biophysical properties affect the spatial distribution of RAS isoforms and their functions.
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Affiliation(s)
- Yong Zhou
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX, United States
| | - Alemayehu A. Gorfe
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX, United States
| | - John F. Hancock
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center, Houston, TX, United States
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Elaiophylin Is a Potent Hsp90/ Cdc37 Protein Interface Inhibitor with K-Ras Nanocluster Selectivity. Biomolecules 2021; 11:biom11060836. [PMID: 34199986 PMCID: PMC8229862 DOI: 10.3390/biom11060836] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/27/2021] [Accepted: 06/01/2021] [Indexed: 12/19/2022] Open
Abstract
The natural product elaiophylin is a macrodiolide with a broad range of biological activities. However, no direct target of elaiophylin in eukaryotes has been described so far, which hinders a systematic explanation of its astonishing activity range. We recently showed that the related conglobatin A, a protein–protein interface inhibitor of the interaction between the N-terminus of Hsp90 and its cochaperone Cdc37, blocks cancer stem cell properties by selectively inhibiting K-Ras4B but not H-Ras. Here, we elaborated that elaiophylin likewise disrupts the Hsp90/ Cdc37 interaction, without affecting the ATP-pocket of Hsp90. Similarly to conglobatin A, elaiophylin decreased expression levels of the Hsp90 client HIF1α, a transcription factor with various downstream targets, including galectin-3. Galectin-3 is a nanocluster scaffold of K-Ras, which explains the K-Ras selectivity of Hsp90 inhibitors. In agreement with this K-Ras targeting and the potent effect on other Hsp90 clients, we observed with elaiophylin treatment a submicromolar IC50 for MDA-MB-231 and MIA-PaCa-2 3D spheroid formation. Finally, a strong inhibition of MDA-MB-231 cells grown in the chorioallantoic membrane (CAM) microtumor model was determined. These results suggest that several other macrodiolides may have the Hsp90/ Cdc37 interface as a target site.
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Zhou Y, Prakash PS, Liang H, Gorfe AA, Hancock JF. The KRAS and other prenylated polybasic domain membrane anchors recognize phosphatidylserine acyl chain structure. Proc Natl Acad Sci U S A 2021; 118:e2014605118. [PMID: 33526670 PMCID: PMC8017956 DOI: 10.1073/pnas.2014605118] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
KRAS interacts with the inner leaflet of the plasma membrane (PM) using a hybrid anchor that comprises a lysine-rich polybasic domain (PBD) and a C-terminal farnesyl chain. Electrostatic interactions have been envisaged as the primary determinant of interactions between KRAS and membranes. Here, we integrated molecular dynamics (MD) simulations and superresolution spatial analysis in mammalian cells and systematically compared four equally charged KRAS anchors: the wild-type farnesyl hexa-lysine and engineered mutants comprising farnesyl hexa-arginine, geranylgeranyl hexa-lysine, and geranylgeranyl hexa-arginine. MD simulations show that these equally charged KRAS mutant anchors exhibit distinct interactions and packing patterns with different phosphatidylserine (PtdSer) species, indicating that prenylated PBD-bilayer interactions extend beyond electrostatics. Similar observations were apparent in intact cells, where each anchor exhibited binding specificities for PtdSer species with distinct acyl chain compositions. Acyl chain composition determined responsiveness of the spatial organization of different PtdSer species to diverse PM perturbations, including transmembrane potential, cholesterol depletion, and PM curvature. In consequence, the spatial organization and PM binding of each KRAS anchor precisely reflected the behavior of its preferred PtdSer ligand to these same PM perturbations. Taken together these results show that small GTPase PBD-prenyl anchors, such as that of KRAS, have the capacity to encode binding specificity for specific acyl chains as well as lipid headgroups, which allow differential responses to biophysical perturbations that may have biological and signaling consequences for the anchored GTPase.
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Affiliation(s)
- Yong Zhou
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030
- Graduate School of Biological Sciences, MD Anderson Cancer Center and University of Texas Health Science Center, Houston, TX 77030
| | - Priyanka S Prakash
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030
| | - Hong Liang
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030
| | - Alemayehu A Gorfe
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030
- Graduate School of Biological Sciences, MD Anderson Cancer Center and University of Texas Health Science Center, Houston, TX 77030
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center, Houston, TX 77030;
- Graduate School of Biological Sciences, MD Anderson Cancer Center and University of Texas Health Science Center, Houston, TX 77030
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12
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Interaction of drugs with lipid raft membrane domains as a possible target. Drug Target Insights 2021; 14:34-47. [PMID: 33510571 PMCID: PMC7832984 DOI: 10.33393/dti.2020.2185] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2020] [Accepted: 11/11/2020] [Indexed: 01/23/2023] Open
Abstract
Introduction Plasma membranes are not the homogeneous bilayers of uniformly distributed lipids but the lipid complex with laterally separated lipid raft membrane domains, which provide receptor, ion channel and enzyme proteins with a platform. The aim of this article is to review the mechanistic interaction of drugs with membrane lipid rafts and address the question whether drugs induce physicochemical changes in raft-constituting and raft-surrounding membranes. Methods Literature searches of PubMed/MEDLINE and Google Scholar databases from 2000 to 2020 were conducted to include articles published in English in internationally recognized journals. Collected articles were independently reviewed by title, abstract and text for relevance. Results The literature search indicated that pharmacologically diverse drugs interact with raft model membranes and cellular membrane lipid rafts. They could physicochemically modify functional protein-localizing membrane lipid rafts and the membranes surrounding such domains, affecting the raft organizational integrity with the resultant exhibition of pharmacological activity. Raft-acting drugs were characterized as ones to decrease membrane fluidity, induce liquid-ordered phase or order plasma membranes, leading to lipid raft formation; and ones to increase membrane fluidity, induce liquid-disordered phase or reduce phase transition temperature, leading to lipid raft disruption. Conclusion Targeting lipid raft membrane domains would open a new way for drug design and development. Since angiotensin-converting enzyme 2 receptors which are a cell-specific target of and responsible for the cellular entry of novel coronavirus are localized in lipid rafts, agents that specifically disrupt the relevant rafts may be a drug against coronavirus disease 2019.
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13
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Zhou Y, Hancock JF. Super-Resolution Imaging and Spatial Analysis of RAS on Intact Plasma Membrane Sheets. Methods Mol Biol 2021; 2262:217-232. [PMID: 33977479 PMCID: PMC10010057 DOI: 10.1007/978-1-0716-1190-6_12] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The function of lipid-anchored small GTPases RAS proteins is mostly compartmentalized to the plasma membrane (PM). Complex biophysical interactions between the C-terminal membrane-anchoring domains of RAS isoforms and PM lipids drive spatial segregation of RAS molecules in the formation of nanometer-sized domains, termed as nanoclusters. These RAS/lipid proteolipid nano-assemblies are the main sites for efficient effector recruitment and signal transduction. Here, we describe a super-resolution imaging method to quantify the nanometer-sized nanoclustering of RAS over a length scale between 8 and 240 nm on intact PM sheets of mammalian cells. Detailed molecular spatial distribution parameters, including the extent of nanoclustering, average cluster size, clustered fraction, and population distribution can be obtained by the univariate spatial distribution analysis. Intermolecular associations between different RAS isoforms, RAS and various PM lipids, as well as RAS and diverse effectors can be quantified via bivariate co-localization analysis.
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Affiliation(s)
- Yong Zhou
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA.
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, TX, USA
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14
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Kara S, Amon L, Lühr JJ, Nimmerjahn F, Dudziak D, Lux A. Impact of Plasma Membrane Domains on IgG Fc Receptor Function. Front Immunol 2020; 11:1320. [PMID: 32714325 PMCID: PMC7344230 DOI: 10.3389/fimmu.2020.01320] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 05/26/2020] [Indexed: 12/13/2022] Open
Abstract
Lipid cell membranes not only represent the physical boundaries of cells. They also actively participate in many cellular processes. This contribution is facilitated by highly complex mixtures of different lipids and incorporation of various membrane proteins. One group of membrane-associated receptors are Fc receptors (FcRs). These cell-surface receptors are crucial for the activity of most immune cells as they bind immunoglobulins such as immunoglobulin G (IgG). Based on distinct mechanisms of IgG binding, two classes of Fc receptors are now recognized: the canonical type I FcγRs and select C-type lectin receptors newly referred to as type II FcRs. Upon IgG immune complex induced cross-linking, these receptors are known to induce a multitude of cellular effector responses in a cell-type dependent manner, including internalization, antigen processing, and presentation as well as production of cytokines. The response is also determined by specific intracellular signaling domains, allowing FcRs to either positively or negatively modulate immune cell activity. Expression of cell-type specific combinations and numbers of receptors therefore ultimately sets a threshold for induction of effector responses. Mechanistically, receptor cross-linking and localization to lipid rafts, i.e., organized membrane microdomains enriched in intracellular signaling proteins, were proposed as major determinants of initial FcR activation. Given that immune cell membranes might also vary in their lipid compositions, it is reasonable to speculate, that the cell membrane and especially lipid rafts serve as an additional regulator of FcR activity. In this article, we aim to summarize the current knowledge on the interplay of lipid rafts and IgG binding FcRs with a focus on the plasma membrane composition and receptor localization in immune cells, the proposed mechanisms underlying this localization and consequences for FcR function with respect to their immunoregulatory capacity.
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Affiliation(s)
- Sibel Kara
- Department of Biology, Institute of Genetics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Lukas Amon
- Laboratory of Dendritic Cell Biology, Department of Dermatology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
| | - Jennifer J Lühr
- Laboratory of Dendritic Cell Biology, Department of Dermatology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Division of Nano-Optics, Max-Planck Institute for the Science of Light, Erlangen, Germany
| | - Falk Nimmerjahn
- Department of Biology, Institute of Genetics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Medical Immunology Campus Erlangen (MICE), Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Deutsches Zentrum Immuntherapie (DZI), Erlangen, Germany
| | - Diana Dudziak
- Laboratory of Dendritic Cell Biology, Department of Dermatology, University Hospital Erlangen, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Medical Immunology Campus Erlangen (MICE), Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Deutsches Zentrum Immuntherapie (DZI), Erlangen, Germany.,Comprehensive Cancer Center Erlangen-European Metropolitan Area of Nürnberg (CCC ER-EMN), Erlangen, Germany
| | - Anja Lux
- Department of Biology, Institute of Genetics, Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany.,Medical Immunology Campus Erlangen (MICE), Friedrich-Alexander University Erlangen-Nürnberg (FAU), Erlangen, Germany
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15
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Bie N, Han L, Meng M, Yan Z, Wang C. The immunomodulatory effect of docosahexaenoic acid (DHA) on the RAW264.7 cells by modification of the membrane structure and function. Food Funct 2020; 11:2603-2616. [DOI: 10.1039/c9fo02618e] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
DHA can regulate various physiological functions of cells. Our group has clarified the immunomodulatory activity and molecular mechanism of DHA on RAW264.7 cells.
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Affiliation(s)
- Nana Bie
- “State Key Laboratory of Food Nutrition and Safety”
- Key Laboratory of Food Nutrition and Safety
- Ministry of Education
- College of Food Engineering and Biotechnology
- Tianjin University of Science and Technology
| | - Lirong Han
- “State Key Laboratory of Food Nutrition and Safety”
- Key Laboratory of Food Nutrition and Safety
- Ministry of Education
- College of Food Engineering and Biotechnology
- Tianjin University of Science and Technology
| | - Meng Meng
- “State Key Laboratory of Food Nutrition and Safety”
- Key Laboratory of Food Nutrition and Safety
- Ministry of Education
- College of Food Engineering and Biotechnology
- Tianjin University of Science and Technology
| | - Zhongli Yan
- “State Key Laboratory of Food Nutrition and Safety”
- Key Laboratory of Food Nutrition and Safety
- Ministry of Education
- College of Food Engineering and Biotechnology
- Tianjin University of Science and Technology
| | - Chunling Wang
- “State Key Laboratory of Food Nutrition and Safety”
- Key Laboratory of Food Nutrition and Safety
- Ministry of Education
- College of Food Engineering and Biotechnology
- Tianjin University of Science and Technology
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16
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Formation of Drug-Participating Catanionic Aggregates for Extended Delivery of Non-Steroidal Anti-Inflammatory Drugs from Contact Lenses. Biomolecules 2019; 9:biom9100593. [PMID: 31658626 PMCID: PMC6843253 DOI: 10.3390/biom9100593] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2019] [Revised: 09/26/2019] [Accepted: 09/27/2019] [Indexed: 11/26/2022] Open
Abstract
This paper focuses on extending drug release duration from contact lenses by incorporating catanionic aggregates. The aggregates consist of a long-chain cationic surfactant, i.e., cetalkonium chloride (CKC), and an oppositely charged anti-inflammatory amphiphilic drug. We studied three non-steroidal anti-inflammatory (NSAID) drugs with different octanol–water partition coefficients; diclofenac sodium (DFNa), flurbiprofen sodium (FBNa), and naproxen sodium (NPNa). Confirmation of catanionic aggregate formation in solution was determined by steady and dynamic shear rheology measurements. We observed the increased viscosity, shear thinning, and viscoelastic behavior characteristic of wormlike micelles; the rheological data are reasonably well described using a Maxwellian fluid model with a single relaxation time. In vitro release experiments demonstrated that the extension in the drug release time is dependent on the ability of a drug to form viscoelastic catanionic aggregates. Such aggregates retard the diffusive transport of drug molecules from the contact lenses. Our study revealed that the release kinetics depends on the CKC concentration and the alkyl chain length of the cationic surfactant. We demonstrated that more hydrophobic drugs such as diclofenac sodium show a more extended release than less hydrophobic drugs such as naproxen sodium.
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17
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Khondker A, Hub JS, Rheinstädter MC. Steroid-steroid interactions in biological membranes: Cholesterol and cortisone. Chem Phys Lipids 2019; 221:193-197. [PMID: 30951711 DOI: 10.1016/j.chemphyslip.2019.04.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Revised: 03/27/2019] [Accepted: 04/01/2019] [Indexed: 11/17/2022]
Abstract
Steroid flares are common side effects associated with corticosteroid treatment, and have been recently theorized to be a consequence of drug crystallization. It was previously reported that the lipid bilayer can promote crystallization of cortisone at high local concentrations. Here, we studied the effect of cholesterol on this membrane induced cortisone crystallization. By combining x-ray diffraction and Molecular Dynamics simulations we observe that that the presence of cholesterol suppresses cortisone-induced membrane thinning and cortisone transnucleation. Cortisone located in the head-tail interface of the membranes also in the presence of cholesterol. The cholesterol molecules were found to be tilted and displaced towards the bilayer center as function of cortisone concentration, away from their canonical position. Our results show that membrane cholesterol may play an important role in the ability of lipid bilayers to catalyze the formation of corticosteroid crystallites.
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Affiliation(s)
- Adree Khondker
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada; Origins Institute, McMaster University, Hamilton, Ontario, Canada
| | - Jochen S Hub
- Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany
| | - Maikel C Rheinstädter
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada; Origins Institute, McMaster University, Hamilton, Ontario, Canada.
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18
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Functional link between plasma membrane spatiotemporal dynamics, cancer biology, and dietary membrane-altering agents. Cancer Metastasis Rev 2019; 37:519-544. [PMID: 29860560 DOI: 10.1007/s10555-018-9733-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The cell plasma membrane serves as a nexus integrating extra- and intracellular components, which together enable many of the fundamental cellular signaling processes that sustain life. In order to perform this key function, plasma membrane components assemble into well-defined domains exhibiting distinct biochemical and biophysical properties that modulate various signaling events. Dysregulation of these highly dynamic membrane domains can promote oncogenic signaling. Recently, it has been demonstrated that select membrane-targeted dietary bioactives (MTDBs) have the ability to remodel plasma membrane domains and subsequently reduce cancer risk. In this review, we focus on the importance of plasma membrane domain structural and signaling functionalities as well as how loss of membrane homeostasis can drive aberrant signaling. Additionally, we discuss the intricacies associated with the investigation of these membrane domain features and their associations with cancer biology. Lastly, we describe the current literature focusing on MTDBs, including mechanisms of chemoprevention and therapeutics in order to establish a functional link between these membrane-altering biomolecules, tuning of plasma membrane hierarchal organization, and their implications in cancer prevention.
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19
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Zhou Y, Hancock JF. Electron microscopy combined with spatial analysis: quantitative mapping of the nano-assemblies of plasma membrane-associating proteins and lipids. BIOPHYSICS REPORTS 2018; 4:320-328. [PMID: 30596140 PMCID: PMC6276063 DOI: 10.1007/s41048-018-0060-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 02/10/2018] [Indexed: 11/27/2022] Open
Abstract
The plasma membrane (PM) is a complex environment consisting of > 700 species of lipids and many different types of membrane-associating proteins. These lipids and membrane proteins are distributed heterogeneously into nanometer-sized domains, called nanoclusters. The lateral spatial segregation in the PM gives rise to different curvature and lipid composition, which determines the efficiency of effector binding and signal transmission. Here, we describe an electron microscopy (EM)-spatial mapping technique to quantify the extent of nanoclusters formation in the PM. The nano-assemblies in the PM are quantified via expressing the GFP-tagged proteins or lipid-binding domains in the cells, which are then immunolabeled with the gold nanoparticles pre-coupled to the anti-GFP antibody. The gold nanoparticles are visualized via the transmission EM at high magnification. The statistical analysis of the Ripley’s K-function calculates the spatial distribution of the gold nanoparticles. Important spatial parameters, such as the extent of nanoclustering, the clustered fraction, the number of proteins per cluster, the optimal size of a nanocluster, and the number of proteins localized to the PM, can be calculated. Further detailed aggregation pattern, such as the populations of monomers, dimers, trimers, and higher ordered oligomers, can also be extracted from the spatial analysis. The EM-bivariate analysis quantifies the extent of co-localization between two different components in the PM and provides key information on the protein–protein and the protein–lipid interactions over a long-distance scale from 8 to 240 nm.
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Affiliation(s)
- Yong Zhou
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030 USA
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center at Houston, Houston, TX 77030 USA
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20
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Fuentes NR, Mlih M, Barhoumi R, Fan YY, Hardin P, Steele TJ, Behmer S, Prior IA, Karpac J, Chapkin RS. Long-Chain n-3 Fatty Acids Attenuate Oncogenic KRas-Driven Proliferation by Altering Plasma Membrane Nanoscale Proteolipid Composition. Cancer Res 2018; 78:3899-3912. [PMID: 29769200 DOI: 10.1158/0008-5472.can-18-0324] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 03/26/2018] [Accepted: 05/08/2018] [Indexed: 12/26/2022]
Abstract
Ras signaling originates from transient nanoscale compartmentalized regions of the plasma membrane composed of specific proteins and lipids. The highly specific lipid composition of these nanodomains, termed nanoclusters, facilitates effector recruitment and therefore influences signal transduction. This suggests that Ras nanocluster proteolipid composition could represent a novel target for future chemoprevention interventions. There is evidence that consumption of fish oil containing long-chain n-3 polyunsaturated fatty acids (n-3 PUFA) such as eicosapentaenoic acid (EPA, 20:5Δ5,8,11,14,17) and docosahexaenoic acid (DHA, 22:6Δ4,7,10,13,16,19) may reduce colon cancer risk in humans, yet the mechanism underlying this effect is unknown. Here, we demonstrate that dietary n-3 PUFA reduce the lateral segregation of cholesterol-dependent and -independent nanoclusters, suppressing phosphatidic acid-dependent oncogenic KRas effector interactions, via their physical incorporation into plasma membrane phospholipids. This results in attenuation of oncogenic Ras-driven colonic hyperproliferation in both Drosophila and murine models. These findings demonstrate the unique properties of dietary n-3 PUFA in the shaping of Ras nanoscale proteolipid complexes and support the emerging role of plasma membrane-targeted therapies.Significance: The influence of dietary long chain n-3 polyunsaturated fatty acids on plasma membrane protein nanoscale organization and KRas signaling supports development of plasma membrane-targeted therapies in colon cancer.Graphical Abstract: http://cancerres.aacrjournals.org/content/canres/78/14/3899/F1.large.jpg Cancer Res; 78(14); 3899-912. ©2018 AACR.
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Affiliation(s)
- Natividad R Fuentes
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, Texas.,Department of Veterinary Physiology and Pharmacology, Texas A&M University, College Station, Texas
| | - Mohamed Mlih
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, Texas
| | - Rola Barhoumi
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas
| | - Yang-Yi Fan
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, Texas
| | - Paul Hardin
- Department of Biology, Texas A&M University, College Station, Texas
| | - Trevor J Steele
- Department of Entomology, Texas A&M University, College Station, Texas
| | - Spencer Behmer
- Department of Entomology, Texas A&M University, College Station, Texas
| | - Ian A Prior
- Division of Cellular and Molecular Physiology, University of Liverpool, Liverpool, United Kingdom
| | - Jason Karpac
- Department of Molecular and Cellular Medicine, College of Medicine, Texas A&M Health Sciences Center, College Station, Texas
| | - Robert S Chapkin
- Program in Integrative Nutrition and Complex Diseases, Texas A&M University, College Station, Texas. .,Center for Translational Environmental Health Research, Texas A&M University, College Station, Texas
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21
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Fuentes NR, Kim E, Fan YY, Chapkin RS. Omega-3 fatty acids, membrane remodeling and cancer prevention. Mol Aspects Med 2018; 64:79-91. [PMID: 29627343 DOI: 10.1016/j.mam.2018.04.001] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Revised: 03/27/2018] [Accepted: 04/04/2018] [Indexed: 12/20/2022]
Abstract
Proteins are often credited as the macromolecule responsible for performing critical cellular functions, however lipids have recently garnered more attention as our understanding of their role in cell function and human health becomes more apparent. Although cellular membranes are the lipid environment in which many proteins function, it is now apparent that protein and lipid assemblies can be organized to form distinct micro- or nanodomains that facilitate signaling events. Indeed, it is now appreciated that cellular function is partly regulated by the specific spatiotemporal lipid composition of the membrane, down to the nanosecond and nanometer scale. Furthermore, membrane composition is altered during human disease processes such as cancer and obesity. For example, an increased rate of lipid/cholesterol synthesis in cancerous tissues has long been recognized as an important aspect of the rewired metabolism of transformed cells. However, the contribution of lipids/cholesterol to cellular function in disease models is not yet fully understood. Furthermore, an important consideration in regard to human health is that diet is a major modulator of cell membrane composition. This can occur directly through incorporation of membrane substrates, such as fatty acids, e.g., n-3 polyunsaturated fatty acids (n-3 PUFA) and cholesterol. In this review, we describe scenarios in which changes in membrane composition impact human health. Particular focus is placed on the importance of intrinsic lipid/cholesterol biosynthesis and metabolism and extrinsic dietary modification in cancer and its effect on plasma membrane properties.
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Affiliation(s)
- Natividad R Fuentes
- Program in Integrative Nutrition & Complex Diseases, Texas A&M University, USA; Faculty of Toxicology, Texas A&M University, USA
| | - Eunjoo Kim
- Program in Integrative Nutrition & Complex Diseases, Texas A&M University, USA; Department of Molecular and Cellular Medicine, Texas A&M University, USA
| | - Yang-Yi Fan
- Program in Integrative Nutrition & Complex Diseases, Texas A&M University, USA; Department of Nutrition & Food Science, Texas A&M University, USA
| | - Robert S Chapkin
- Program in Integrative Nutrition & Complex Diseases, Texas A&M University, USA; Faculty of Toxicology, Texas A&M University, USA; Department of Nutrition & Food Science, Texas A&M University, USA; Center for Translational Environmental Health Research, Texas A&M University, USA.
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22
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Zhou Y, Hancock JF. Deciphering lipid codes: K-Ras as a paradigm. Traffic 2018; 19:157-165. [PMID: 29120102 PMCID: PMC5927616 DOI: 10.1111/tra.12541] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2017] [Revised: 11/06/2017] [Accepted: 11/06/2017] [Indexed: 01/02/2023]
Abstract
The cell plasma membrane (PM) is a highly dynamic and heterogeneous lipid environment, driven by complex hydrophobic and electrostatic interactions among the hundreds of types of lipid species. Although the biophysical processes governing lipid lateral segregation in the cell PM have been established in vitro, biological implications of lipid heterogeneity are poorly understood. Of particular interest is how membrane proteins potentially utilize transient spatial clustering of PM lipids to regulate function. This review focuses on a lipid-anchored small GTPase K-Ras as an example to explore how its C-terminal membrane-anchoring domain, consisting of a contiguous hexa-lysine polybasic domain and an adjacent farnesyl anchor, possesses a complex coding mechanism for highly selective lipid sorting on the PM. How this lipid specificity modulates K-Ras signal transmission will also be discussed.
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Affiliation(s)
- Yong Zhou
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, 6431, Fannin Street, Houston, TX
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, McGovern Medical School, University of Texas Health Science Center at Houston, 6431, Fannin Street, Houston, TX
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23
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Alsop RJ, Himbert S, Dhaliwal A, Schmalzl K, Rheinstädter MC. Aspirin locally disrupts the liquid-ordered phase. ROYAL SOCIETY OPEN SCIENCE 2018; 5:171710. [PMID: 29515878 PMCID: PMC5830767 DOI: 10.1098/rsos.171710] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2017] [Accepted: 01/23/2018] [Indexed: 06/12/2023]
Abstract
Local structure and dynamics of lipid membranes play an important role in membrane function. The diffusion of small molecules, the curvature of lipids around a protein and the existence of cholesterol-rich lipid domains (rafts) are examples for the membrane to serve as a functional interface. The collective fluctuations of lipid tails, in particular, are relevant for diffusion of membrane constituents and small molecules in and across membranes, and for structure and formation of membrane domains. We studied the effect of aspirin (acetylsalicylic acid, ASA) on local structure and dynamics of membranes composed of dimyristoylphosphocholine (DMPC) and cholesterol. Aspirin is a common analgesic, but is also used in the treatment of cholesterol. Using coherent inelastic neutron scattering experiments and molecular dynamics (MD) simulations, we present evidence that ASA binds to liquid-ordered, raft-like domains and disturbs domain organization and dampens collective fluctuations. By hydrogen-bonding to lipid molecules, ASA forms 'superfluid' complexes with lipid molecules that can organize laterally in superlattices and suppress cholesterol's ordering effect.
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Affiliation(s)
- Richard J. Alsop
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Sebastian Himbert
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Alexander Dhaliwal
- Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada
| | - Karin Schmalzl
- JCNS, Forschungszentrum Jülich GmbH, Jülich Centre for Neutron Science at ILL, Grenoble, France
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24
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Fuentes NR, Salinas ML, Kim E, Chapkin RS. Emerging role of chemoprotective agents in the dynamic shaping of plasma membrane organization. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2017; 1859:1668-1678. [PMID: 28342710 PMCID: PMC5501766 DOI: 10.1016/j.bbamem.2017.03.014] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2016] [Revised: 03/15/2017] [Accepted: 03/19/2017] [Indexed: 12/22/2022]
Abstract
In the context of an organism, epithelial cells by nature are designed to be the defining barrier between self and the outside world. This is especially true for the epithelial cells that form the lining of the digestive tract, which absorb nutrients and serve as a barrier against harmful substances. These cells are constantly bathed by a complex mixture of endogenous (bile acids, mucus, microbial metabolites) and exogenous (food, nutrients, drugs) bioactive compounds. From a cell biology perspective, this type of exposure would directly impact the plasma membrane, which consists of a myriad of complex lipids and proteins. The plasma membrane not only functions as a barrier but also as the medium in which cellular signaling complexes form and function. This property is mediated by the organization of the plasma membrane, which is exquisitely temporally (nanoseconds to minutes) and spatially (nanometers to micrometers) regulated. Since numerous bioactive compounds found in the intestinal lumen can directly interact with lipid membranes, we hypothesize that the dynamic reshaping of plasma membrane organization underlies the chemoprotective effect of select membrane targeted dietary bioactives (MTDBs). This article is part of a Special Issue entitled: Membrane Lipid Therapy: Drugs Targeting Biomembranes edited by Pablo V. Escribá.
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Affiliation(s)
- Natividad R Fuentes
- Program in Integrative Nutrition & Complex Diseases, Texas A&M University, USA; Faculty of Toxicology, Texas A&M University, USA
| | - Michael L Salinas
- Program in Integrative Nutrition & Complex Diseases, Texas A&M University, USA; Department of Nutrition & Food Science, Texas A&M University, USA
| | - Eunjoo Kim
- Program in Integrative Nutrition & Complex Diseases, Texas A&M University, USA; Department of Molecular and Cellular Medicine, Texas A&M University, USA
| | - Robert S Chapkin
- Program in Integrative Nutrition & Complex Diseases, Texas A&M University, USA; Faculty of Toxicology, Texas A&M University, USA; Department of Nutrition & Food Science, Texas A&M University, USA; Center for Translational Environmental Health Research, Texas A&M University, USA.
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25
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López RM, López JE, López JS, Castillo MC, Guevara G, Morales JA, López OA, Lozano J, Castillo EF. Effects of indomethacin on prostanoid synthesis and vasomotor responsiveness in endothelium-denuded abdominal and thoracic aortas of Wistar rats. Clin Exp Hypertens 2017; 39:210-219. [DOI: 10.1080/10641963.2016.1226895] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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26
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Nussinov R, Wang G, Tsai CJ, Jang H, Lu S, Banerjee A, Zhang J, Gaponenko V. Calmodulin and PI3K Signaling in KRAS Cancers. Trends Cancer 2017; 3:214-224. [PMID: 28462395 PMCID: PMC5408465 DOI: 10.1016/j.trecan.2017.01.007] [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] [Indexed: 01/16/2023]
Abstract
Calmodulin (CaM) uniquely promotes signaling of oncogenic K-Ras; but not N-Ras or H-Ras. How CaM interacts with K-Ras and how this stimulates cell proliferation are among the most challenging questions in KRAS-driven cancers. Earlier data pointed to formation of a ternary complex consisting of K-Ras, PI3Kα and CaM. Recent data point to phosphorylated CaM binding to the SH2 domains of the p85 subunit of PI3Kα and activating it. Modeling suggests that the high affinity interaction between the phosphorylated CaM tyrosine motif and PI3Kα, can promote full PI3Kα activation by oncogenic K-Ras. Our up-to-date review discusses CaM's role in PI3K signaling at the membrane in KRAS-driven cancers. This is significant since it may help development of K-Ras-specific pharmacology.
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Affiliation(s)
- Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Guanqiao Wang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Children’s Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200127, China
| | - Chung-Jung Tsai
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, Frederick, MD 21702, U.S.A
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Children’s Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200127, China
| | - Avik Banerjee
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, IL 60607, U.S.A
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Children’s Medical Center, Shanghai Jiao Tong University, School of Medicine, Shanghai, 200127, China
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, IL 60607, U.S.A
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The Molecular Structure of Human Red Blood Cell Membranes from Highly Oriented, Solid Supported Multi-Lamellar Membranes. Sci Rep 2017; 7:39661. [PMID: 28045119 PMCID: PMC5206716 DOI: 10.1038/srep39661] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 11/24/2016] [Indexed: 12/30/2022] Open
Abstract
We prepared highly oriented, multi-lamellar stacks of human red blood cell (RBC) membranes applied on silicon wafers. RBC ghosts were prepared by hemolysis and applied onto functionalized silicon chips and annealed into multi-lamellar RBC membranes. High resolution X-ray diffraction was used to determine the molecular structure of the stacked membranes. We present direct experimental evidence that these RBC membranes consist of nanometer sized domains of integral coiled-coil peptides, as well as liquid ordered (lo) and liquid disordered (ld) lipids. Lamellar spacings, membrane and hydration water layer thicknesses, areas per lipid tail and domain sizes were determined. The common drug aspirin was added to the RBC membranes and found to interact with RBC membranes and preferably partition in the head group region of the lo domain leading to a fluidification of the membranes, i.e., a thinning of the bilayers and an increase in lipid tail spacing. Our results further support current models of RBC membranes as patchy structures and provide unprecedented structural details of the molecular organization in the different domains.
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28
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Ras Proteolipid Nanoassemblies on the Plasma Membrane Sort Lipids With High Selectivity. ACTA ACUST UNITED AC 2017. [DOI: 10.1016/bs.abl.2017.01.001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
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29
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AMPK and Endothelial Nitric Oxide Synthase Signaling Regulates K-Ras Plasma Membrane Interactions via Cyclic GMP-Dependent Protein Kinase 2. Mol Cell Biol 2016; 36:3086-3099. [PMID: 27697864 DOI: 10.1128/mcb.00365-16] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 09/26/2016] [Indexed: 12/22/2022] Open
Abstract
K-Ras must localize to the plasma membrane and be arrayed in nanoclusters for biological activity. We show here that K-Ras is a substrate for cyclic GMP-dependent protein kinases (PKGs). In intact cells, activated PKG2 selectively colocalizes with K-Ras on the plasma membrane and phosphorylates K-Ras at Ser181 in the C-terminal polybasic domain. K-Ras phosphorylation by PKG2 is triggered by activation of AMP-activated protein kinase (AMPK) and requires endothelial nitric oxide synthase and soluble guanylyl cyclase. Phosphorylated K-Ras reorganizes into distinct nanoclusters that retune the signal output. Phosphorylation acutely enhances K-Ras plasma membrane affinity, but phosphorylated K-Ras is progressively lost from the plasma membrane via endocytic recycling. Concordantly, chronic pharmacological activation of AMPK → PKG2 signaling with mitochondrial inhibitors, nitric oxide, or sildenafil inhibits proliferation of K-Ras-positive non-small cell lung cancer cells. The study shows that K-Ras is a target of a metabolic stress-signaling pathway that can be leveraged to inhibit oncogenic K-Ras function.
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30
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The Lipid Bilayer Provides a Site for Cortisone Crystallization at High Cortisone Concentrations. Sci Rep 2016; 6:22425. [PMID: 26936102 PMCID: PMC4776104 DOI: 10.1038/srep22425] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2015] [Accepted: 02/15/2016] [Indexed: 12/20/2022] Open
Abstract
Cortisone is an injected anti-inflammatory drug that can cause painful side effects known as "steroid flares" which are caused by cortisone crystallizing at the injection site. We used molecular dynamics simulations and X-ray diffraction to study the interaction of cortisone with model lipid membranes made of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) at drug concentrations from 0 mol% to 50 mol%. Cortisone was found to partition in the lipid bilayer and locate in the hydrophilic to hydrophobic interface of the membranes. Cortisone strongly affects the integrity of the membrane, as quantified by a decreased membrane thickness, increased area per lipid, and decreased lipid tail order parameters. At cortisone concentrations of more than 20 mol%, signals from crystallized cortisone were observed. These crystallites are embedded in the bilayers and orient with the membranes. While the cortisone molecules align parallel to the bilayers at low concentrations, they start to penetrate the hydrophobic core at higher concentrations. Trans-membrane crystallites start to nucleate when the membrane thickness has decreased such that cortisone molecules in the different leaflets can find partners from the opposite leaflet resulting in a non-zero density of cortisone molecules in the bilayer center. We suggest that the lipid bilayer provides a site for cortisone crystallization.
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31
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Wehrens M, ten Wolde PR, Mugler A. Positive feedback can lead to dynamic nanometer-scale clustering on cell membranes. J Chem Phys 2015; 141:205102. [PMID: 25429963 DOI: 10.1063/1.4901888] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Clustering of molecules on biological membranes is a widely observed phenomenon. A key example is the clustering of the oncoprotein Ras, which is known to be important for signal transduction in mammalian cells. Yet, the mechanism by which Ras clusters form and are maintained remains unclear. Recently, it has been discovered that activated Ras promotes further Ras activation. Here we show using particle-based simulation that this positive feedback is sufficient to produce persistent clusters of active Ras molecules at the nanometer scale via a dynamic nucleation mechanism. Furthermore, we find that our cluster statistics are consistent with experimental observations of the Ras system. Interestingly, we show that our model does not support a Turing regime of macroscopic reaction-diffusion patterning, and therefore that the clustering we observe is a purely stochastic effect, arising from the coupling of positive feedback with the discrete nature of individual molecules. These results underscore the importance of stochastic and dynamic properties of reaction diffusion systems for biological behavior.
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Affiliation(s)
- Martijn Wehrens
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | | | - Andrew Mugler
- FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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32
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Raghunathan K, Ahsan A, Ray D, Nyati MK, Veatch SL. Membrane Transition Temperature Determines Cisplatin Response. PLoS One 2015; 10:e0140925. [PMID: 26484687 PMCID: PMC4618528 DOI: 10.1371/journal.pone.0140925] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Accepted: 10/01/2015] [Indexed: 11/19/2022] Open
Abstract
Cisplatin is a classical chemotherapeutic agent used in treating several forms of cancer including head and neck. However, cells develop resistance to the drug in some patients through a range of mechanisms, some of which are poorly understood. Using isolated plasma membrane vesicles as a model system, we present evidence suggesting that cisplatin induced resistance may be due to certain changes in the bio-physical properties of plasma membranes. Giant plasma membrane vesicles (GPMVs) isolated from cortical cytoskeleton exhibit a miscibility transition between a single liquid phase at high temperature and two distinct coexisting liquid phases at low temperature. The temperature at which this transition occurs is hypothesized to reflect the magnitude of membrane heterogeneity at physiological temperature. We find that addition of cisplatin to vesicles isolated from cisplatin-sensitive cells result in a lowering of this miscibility transition temperature, whereas in cisplatin-resistant cells such treatment does not affect the transition temperature. To explore if this is a cause or consequence of cisplatin resistance, we tested if addition of cisplatin in combination with agents that modulate GPMV transition temperatures can affect cisplatin sensitivity. We found that cells become more sensitive to cisplatin when isopropanol, an agent that lowers GPMV transition temperature, was combined with cisplatin. Conversely, cells became resistant to cisplatin when added in combination with menthol that raises GPMV transition temperatures. These data suggest that changes in plasma membrane heterogeneity augments or suppresses signaling events initiated in the plasma membranes that can determine response to cisplatin. We postulate that desired perturbations of membrane heterogeneity could provide an effective therapeutic strategy to overcome cisplatin resistance for certain patients.
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Affiliation(s)
- Krishnan Raghunathan
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Aarif Ahsan
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Dipankar Ray
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Mukesh K. Nyati
- Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Sarah L. Veatch
- Department of Biophysics, University of Michigan, Ann Arbor, Michigan, United States of America
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Chavan TS, Muratcioglu S, Marszalek R, Jang H, Keskin O, Gursoy A, Nussinov R, Gaponenko V. Plasma membrane regulates Ras signaling networks. CELLULAR LOGISTICS 2015; 5:e1136374. [PMID: 27054048 PMCID: PMC4820813 DOI: 10.1080/21592799.2015.1136374] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/15/2015] [Accepted: 12/17/2015] [Indexed: 12/31/2022]
Abstract
Ras GTPases activate more than 20 signaling pathways, regulating such essential cellular functions as proliferation, survival, and migration. How Ras proteins control their signaling diversity is still a mystery. Several pieces of evidence suggest that the plasma membrane plays a critical role. Among these are: (1) selective recruitment of Ras and its effectors to particular localities allowing access to Ras regulators and effectors; (2) specific membrane-induced conformational changes promoting Ras functional diversity; and (3) oligomerization of membrane-anchored Ras to recruit and activate Raf. Taken together, the membrane does not only attract and retain Ras but also is a key regulator of Ras signaling. This can already be gleaned from the large variability in the sequences of Ras membrane targeting domains, suggesting that localization, environment and orientation are important factors in optimizing the function of Ras isoforms.
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Affiliation(s)
- Tanmay Sanjeev Chavan
- Department of Medicinal Chemistry; University of Illinois at Chicago; Chicago, IL USA
| | - Serena Muratcioglu
- Center for Computational Biology and Bioinformatics; Koc University; Istanbul, Turkey
| | - Richard Marszalek
- Department of Biochemistry and Molecular Genetics; University of Illinois at Chicago; Chicago, IL USA
| | - Hyunbum Jang
- Cancer and Inflammation Program; Basic Science Program; Leidos Biomedical Research, Inc.; Frederick National Laboratory for Cancer Research; National Cancer Institute at Frederick; Frederick, MD USA
| | - Ozlem Keskin
- Center for Computational Biology and Bioinformatics; Koc University; Istanbul, Turkey
| | - Attila Gursoy
- Center for Computational Biology and Bioinformatics; Koc University; Istanbul, Turkey
| | - Ruth Nussinov
- Cancer and Inflammation Program; Basic Science Program; Leidos Biomedical Research, Inc.; Frederick National Laboratory for Cancer Research; National Cancer Institute at Frederick; Frederick, MD USA
- Sackler Institute of Molecular Medicine; Department of Human Genetics and Molecular Medicine; Sackler School of Medicine; Tel Aviv University; Tel Aviv, Israel
| | - Vadim Gaponenko
- Department of Biochemistry and Molecular Genetics; University of Illinois at Chicago; Chicago, IL USA
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34
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Šolman M, Ligabue A, Blaževitš O, Jaiswal A, Zhou Y, Liang H, Lectez B, Kopra K, Guzmán C, Härmä H, Hancock JF, Aittokallio T, Abankwa D. Specific cancer-associated mutations in the switch III region of Ras increase tumorigenicity by nanocluster augmentation. eLife 2015; 4:e08905. [PMID: 26274561 PMCID: PMC4563131 DOI: 10.7554/elife.08905] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Accepted: 08/13/2015] [Indexed: 01/09/2023] Open
Abstract
Hotspot mutations of Ras drive cell transformation and tumorigenesis. Less frequent mutations in Ras are poorly characterized for their oncogenic potential. Yet insight into their mechanism of action may point to novel opportunities to target Ras. Here, we show that several cancer-associated mutations in the switch III region moderately increase Ras activity in all isoforms. Mutants are biochemically inconspicuous, while their clustering into nanoscale signaling complexes on the plasma membrane, termed nanocluster, is augmented. Nanoclustering dictates downstream effector recruitment, MAPK-activity, and tumorigenic cell proliferation. Our results describe an unprecedented mechanism of signaling protein activation in cancer. DOI:http://dx.doi.org/10.7554/eLife.08905.001 Cancer is a disease that develops when cells within the body acquire genetic mutations that allow them to grow and divide rapidly. Many human cancers have mutations in a gene that encodes a protein called Ras, which promotes cell growth and division by controlling the activities of other proteins. Ras congregates at the membrane that surrounds the cell and can assemble into clusters (called nanoclusters) that each contain six to eight Ras proteins. The tight packing of the proteins in these nanoclusters increases the amount of Ras in the membrane locally, which allows Ras to interact with other proteins more efficiently to promote growth and cell division. In normal cells, other proteins control when Ras is active. However, in many cancer cells, Ras is active all the time due to mutations that occur in three ‘hotspots’ within its gene. Other mutations in the gene that encodes Ras are also found in cancer cells, but these are less common and it is not clear how they alter the activity of the protein. Here, Solman et al. used microscopy and biochemical techniques to study the effects of some of the less common mutations on Ras activity in human cells. The experiments show that several mutations that alter a region of Ras called the ‘switch III region’ moderately increase the activity of Ras. The mutations probably alter the way that Ras sits in the membrane, which in turn changes the way it interacts with other proteins and the membrane so that more Ras nanoclusters form. Solman et al.'s findings reveal a new way that Ras can be activated in cancer cells. The next challenge is to develop drugs that block the formation of Ras nanoclusters and to find out if they have the potential to be used to treat cancer. DOI:http://dx.doi.org/10.7554/eLife.08905.002
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Affiliation(s)
- Maja Šolman
- Turku Centre for Biotechnology, Åbo Akademi University, Turku, Finland
| | - Alessio Ligabue
- Turku Centre for Biotechnology, Åbo Akademi University, Turku, Finland
| | - Olga Blaževitš
- Turku Centre for Biotechnology, Åbo Akademi University, Turku, Finland
| | - Alok Jaiswal
- Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Yong Zhou
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, United States
| | - Hong Liang
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, United States
| | - Benoit Lectez
- Turku Centre for Biotechnology, Åbo Akademi University, Turku, Finland
| | - Kari Kopra
- Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku, Turku, Finland
| | - Camilo Guzmán
- Turku Centre for Biotechnology, Åbo Akademi University, Turku, Finland
| | - Harri Härmä
- Department of Cell Biology and Anatomy, Institute of Biomedicine, University of Turku, Turku, Finland
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, University of Texas Health Science Center at Houston, Houston, United States
| | - Tero Aittokallio
- Institute for Molecular Medicine Finland, University of Helsinki, Helsinki, Finland
| | - Daniel Abankwa
- Turku Centre for Biotechnology, Åbo Akademi University, Turku, Finland
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35
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Alsop RJ, Armstrong CL, Maqbool A, Toppozini L, Dies H, Rheinstädter MC. Cholesterol expels ibuprofen from the hydrophobic membrane core and stabilizes lamellar phases in lipid membranes containing ibuprofen. SOFT MATTER 2015; 11:4756-4767. [PMID: 25915907 DOI: 10.1039/c5sm00597c] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
There is increasing evidence that common drugs, such as aspirin and ibuprofen, interact with lipid membranes. Ibuprofen is one of the most common over the counter drugs in the world, and is used for relief of pain and fever. It interacts with the cyclooxygenase pathway leading to inhibition of prostaglandin synthesis. From X-ray diffraction of highly oriented model membranes containing between 0 and 20 mol% ibuprofen, 20 mol% cholesterol, and dimyristoylphosphatidylcholine (DMPC), we present evidence for a non-specific interaction between ibuprofen and cholesterol in lipid bilayers. At a low ibuprofen concentrations of 2 mol%, three different populations of ibuprofen molecules were found: two in the lipid head group region and one in the hydrophobic membrane core. At higher ibuprofen concentrations of 10 and 20 mol%, the lamellar bilayer structure is disrupted and a lamellar to cubic phase transition was observed. In the presence of 20 mol% cholesterol, ibuprofen (at 5 mol%) was found to be expelled from the membrane core and reside solely in the head group region of the bilayers. 20 mol% cholesterol was found to stabilize lamellar membrane structure and the formation of a cubic phase at 10 and 20 mol% ibuprofen was suppressed. The results demonstrate that ibuprofen interacts with lipid membranes and that the interaction is strongly dependent on the presence of cholesterol.
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Affiliation(s)
- Richard J Alsop
- Department of Physics and Astronomy, McMaster University, ABB-241, 1280 Main Street West, Hamilton, Ontario L8S 4M1, Canada.
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36
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Alsop RJ, Toppozini L, Marquardt D, Kučerka N, Harroun TA, Rheinstädter MC. Aspirin inhibits formation of cholesterol rafts in fluid lipid membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2015; 1848:805-12. [DOI: 10.1016/j.bbamem.2014.11.023] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2014] [Revised: 11/18/2014] [Accepted: 11/19/2014] [Indexed: 12/20/2022]
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37
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Najumudeen AK, Guzmán C, Posada IMD, Abankwa D. Rab-NANOPS: FRET biosensors for Rab membrane nanoclustering and prenylation detection in mammalian cells. Methods Mol Biol 2015; 1298:29-45. [PMID: 25800830 DOI: 10.1007/978-1-4939-2569-8_3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Rab proteins constitute the largest subfamily of Ras-like small GTPases. They are central to vesicular transport and organelle definition in eukaryotic cells. Unlike their Ras counterparts, they are not a hallmark of cancer. However, a number of diseases, including cancer, show a misregulation of Rab protein activity. As for all membrane-anchored signaling proteins, correct membrane organization is critical for Rabs to operate. In this chapter, we provide a detailed protocol for the use of a flow cytometry-based Fluorescence Resonance Energy Transfer (FRET)-biosensors assay, which allows to detect changes in membrane anchorage, subcellular distribution, and of the nanoscale organization of Rab-GTPases in mammalian cell lines. This assay is high-throughput amenable and can therefore be utilized in chemical-genomic and drug discovery efforts.
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Affiliation(s)
- Arafath Kaja Najumudeen
- Turku Centre for Biotechnology, Åbo Akademi University, Tykistökatu 6B, 20520, Turku, Finland
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38
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Timocin T, Ila HB. Investigation of flurbiprofen genotoxicity and cytotoxicity in rat bone marrow cells. Drug Chem Toxicol 2014; 38:355-60. [DOI: 10.3109/01480545.2014.968933] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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39
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Guzmán C, Solman M, Abankwa D. Nanoclustering and heterogeneous membrane diffusion of Ras studied by FRAP and RICS analysis. Methods Mol Biol 2014; 1120:307-26. [PMID: 24470034 DOI: 10.1007/978-1-62703-791-4_20] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Fluorescence Recovery After Photobleaching (FRAP) and Raster Image Correlation Spectroscopy (RICS) are two powerful techniques to study the diffusion dynamics of fluorescently labeled proteins. FRAP and RICS can be easily applied on any commercial confocal microscope. In this chapter, we describe the principles of these methods and provide the reader with a detailed guide on how to apply these methods in the study of Ras nanoclustering and diffusion in the plasma membrane of live cells.
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Affiliation(s)
- Camilo Guzmán
- Turku Centre for Biotechnology, Åbo Akademi University, Turku, Finland
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40
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Lönnroth C, Andersson M, Asting AG, Nordgren S, Lundholm K. Preoperative low dose NSAID treatment influences the genes for stemness, growth, invasion and metastasis in colorectal cancer. Int J Oncol 2014; 45:2208-20. [PMID: 25340937 PMCID: PMC4215588 DOI: 10.3892/ijo.2014.2686] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2014] [Accepted: 08/21/2014] [Indexed: 02/06/2023] Open
Abstract
Preclinical data, and an increasing list of clinical investigations, show anti-inflammatory agents to favourably influence the biology of colorectal tumor. We have earlier reported on re-expression of activated immune cells after three days preoperative treatment of patients with colorectal carcinoma, randomized to receive oral NSAID (indomethacin or celebrex). Antisecretory prophylaxis (esomeprasol) was provided to all patients and served as sham treatment. Concomittant to MHC locus activation, Prominin1/CD133, a marker associated with stemness and poor prognosis in several solid tumors, was downregulated. The aim of the present study was to evaluate expression of additional regulators belonging to the stem cell niche, OCT4, SOX2 and BMP7, as well as some microRNAs, reported to act as tumor suppressors or oncomiRs. Peroperative tumor biopsies were analyzed by microarrays, quantitative real-time PCR and immunohistochemistry (IHC). The stem cell master regulator SOX2 was increased by NSAIDs (p<0.01), as well as the tumor suppressor miR-630 (p<0.01), while BMP7, a marker for poor prognosis in CRC, was downregulated by NSAID (indomethacin, p<0.02). The upregulation of SOX2, but not of its heterodimer binding partner OCT4, could imply a negative feed-back loop, with a switch‑off for stemness preservation of tumor cells. This is supported by the overall evaluation of gene expression profiles with subsequent events, indicating less aggressive tumors following NSAID treatment.
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Affiliation(s)
- Christina Lönnroth
- Department of Surgery, Surgical Metabolic Research Laboratory at Lundberg Laboratory for Cancer Research, Sahlgrenska University Hospital, University of Gothenburg, SE 413 45 Gothenburg, Sweden
| | - Marianne Andersson
- Department of Surgery, Surgical Metabolic Research Laboratory at Lundberg Laboratory for Cancer Research, Sahlgrenska University Hospital, University of Gothenburg, SE 413 45 Gothenburg, Sweden
| | - Annika G Asting
- Department of Surgery, Surgical Metabolic Research Laboratory at Lundberg Laboratory for Cancer Research, Sahlgrenska University Hospital, University of Gothenburg, SE 413 45 Gothenburg, Sweden
| | - Svante Nordgren
- Department of Surgery, Surgical Metabolic Research Laboratory at Lundberg Laboratory for Cancer Research, Sahlgrenska University Hospital, University of Gothenburg, SE 413 45 Gothenburg, Sweden
| | - Kent Lundholm
- Department of Surgery, Surgical Metabolic Research Laboratory at Lundberg Laboratory for Cancer Research, Sahlgrenska University Hospital, University of Gothenburg, SE 413 45 Gothenburg, Sweden
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41
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Zhou Y, Hancock JF. Ras nanoclusters: Versatile lipid-based signaling platforms. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1853:841-9. [PMID: 25234412 DOI: 10.1016/j.bbamcr.2014.09.008] [Citation(s) in RCA: 174] [Impact Index Per Article: 17.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Revised: 09/05/2014] [Accepted: 09/08/2014] [Indexed: 12/31/2022]
Abstract
Ras proteins assemble into transient nanoclusters on the plasma membrane. Nanoclusters are the sites of Ras effector recruitment and activation and are therefore essential for signal transmission. The dynamics of nanocluster formation and disassembly result in interesting emergent properties including high-fidelity signal transmission. More recently the lipid structure of Ras nanoclusters has been reported and shown to contribute to isoform-specific Ras signaling. In addition specific lipids play critical roles in mediating the formation, stability and dynamics of Ras nanoclusters. In consequence the spatiotemporal organization of these lipids has emerged as important and novel regulators of Ras function. This article is part of a Special Issue entitled: Nanoscale membrane organisation and signalling.
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Affiliation(s)
- Yong Zhou
- Department of Integrative Biology and Pharmacology, University of Texas Medical School, Houston, TX 77030, USA.
| | - John F Hancock
- Department of Integrative Biology and Pharmacology, University of Texas Medical School, Houston, TX 77030, USA.
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42
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Kim KN, Yang HW, Ko SC, Ko YJ, Kim EA, Roh SW, Ko EY, Ahn G, Heo SJ, Jeon YJ, Yoon WJ, Hyun CG, Kim D. 6-7-Dimethoxy-4-methylcoumarin suppresses pro-inflammatory mediator expression through inactivation of the NF-κB and MAPK pathways in LPS-induced RAW 264.7 cells. EXCLI JOURNAL 2014; 13:792-800. [PMID: 26417302 PMCID: PMC4464263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 06/26/2014] [Indexed: 11/17/2022]
Abstract
In this study, we investigated the ability of 6,7-dimethoxy-4-methylcoumarin (DMC) to inhibit lipopolysaccharide (LPS)-induced expression of pro-inflammatory mediators in mouse macrophage (RAW 264.7) cells, and the molecular mechanism through which this inhibition occurred. Our results indicated that DMC downregulated LPS-induced nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, thereby reducing the production of NO and prostaglandin E2 (PGE2) in LPS-activated RAW 264.7 cells. Furthermore, DMC suppressed LPS-induced production of pro-inflammatory cytokines such as interleukin (IL)-1ß, IL-6, and tumor necrosis factor (TNF)-α. To elucidate the mechanism underlying the anti-inflammatory activity of DMC, we assessed its effects on the mitogen-activated protein kinase (MAPK) pathway and the activity and expression of nuclear transcription factor kappa-B (NF-κB). The experiments demonstrated that DMC inhibited LPS-induced phosphorylation of extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinase (JNK), and p38. In addition, it attenuated LPS-induced NF-κB activation via the inhibition of IκB-α phosphorylation. Taken together, these data suggest that DMC exerts its anti-inflammatory effects in RAW 264.7 cells through the inhibition of LPS-stimulated NF-κB and MAPK signaling, thereby downregulating the expression of pro-inflammatory mediators.
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Affiliation(s)
- Kil-Nam Kim
- Jeju Center, Korea Basic Science Institute (KBSI), Jeju 690-140, Republic of Korea
| | - Hye-Won Yang
- School of Marine Biomedical Sciences, Jeju National University, Jeju 690-756, Republic of Korea
| | - Seok-Chun Ko
- School of Marine Biomedical Sciences, Jeju National University, Jeju 690-756, Republic of Korea
| | - Yeong-Jong Ko
- Jeju Biodiversity Research Institute, Jeju Technopark, Jeju 699-943, Republic of Korea
| | - Eun-A Kim
- School of Marine Biomedical Sciences, Jeju National University, Jeju 690-756, Republic of Korea
| | - Seong Woon Roh
- Jeju Center, Korea Basic Science Institute (KBSI), Jeju 690-140, Republic of Korea
| | - Eun-Yi Ko
- School of Marine Biomedical Sciences, Jeju National University, Jeju 690-756, Republic of Korea
| | - Ginnae Ahn
- Department of Marine Bio-Food Sciences, Chonnam National University, Yeosu 550-749, Republic of Korea
| | - Soo-Jin Heo
- Global Bioresources Research Center, Korea Institute of Ocean Science & Technology, Ansan 426-744, Republic of Korea
| | - You-Jin Jeon
- School of Marine Biomedical Sciences, Jeju National University, Jeju 690-756, Republic of Korea
| | - Weon-Jong Yoon
- Jeju Biodiversity Research Institute, Jeju Technopark, Jeju 699-943, Republic of Korea
| | - Chang-Gu Hyun
- LINC Agency, Jeju National University, Jeju 690-756, Republic of Korea,*To whom correspondence should be addressed: Daekyung Kim, Jeju Center, Korea Basic Science Institute (KBSI), Jeju 690-140, Republic of Korea, Tel.: +82-64-800-4930 , FAX: +82-64-805-7800, E-mail:
| | - Daekyung Kim
- Jeju Center, Korea Basic Science Institute (KBSI), Jeju 690-140, Republic of Korea,*To whom correspondence should be addressed: Daekyung Kim, Jeju Center, Korea Basic Science Institute (KBSI), Jeju 690-140, Republic of Korea, Tel.: +82-64-800-4930 , FAX: +82-64-805-7800, E-mail:
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Purssell E. Cyclooxygenase inhibitors inhibit antibody response through interference with MAPK/ERK pathways and BLIMP-1 inhibition. Med Hypotheses 2014; 83:372-7. [PMID: 25012778 DOI: 10.1016/j.mehy.2014.06.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2014] [Revised: 06/09/2014] [Accepted: 06/17/2014] [Indexed: 11/16/2022]
Abstract
Fever is a common symptom of illness in children, and although not harmful in itself, fever and its associated symptoms are often treated with antipyretic drugs. A number of national and other guidelines now recommend against their routine use; a conclusion that was initially supported by a study showing that the prophylactic use of paracetamol might reduce antibody response to some vaccine antigens, although data from booster vaccinations are more equivocal. Although in vivo data on the cause of this inhibition are scarce, in vitro data suggests that the cause may be due to inhibition of the mitogen activated protein kinase/extracellular regulated protein kinase pathways, and a subsequent reduction in the process of plasma cell differentiation at the beginning of the antibody response. This suggests that in high-risk patients these drugs could be avoided in the early part of an infection when plasma-cell differentiation is occurring. More data are needed to define this period; until then existing data support the recommendation against the routine use of these drugs.
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Affiliation(s)
- E Purssell
- King's College London, James Clerk Maxwell Building, 57 Waterloo Road, London SE1 8WA, United Kingdom.
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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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Ariotti N, Fernández-Rojo MA, Zhou Y, Hill MM, Rodkey TL, Inder KL, Tanner LB, Wenk MR, Hancock JF, Parton RG. Caveolae regulate the nanoscale organization of the plasma membrane to remotely control Ras signaling. ACTA ACUST UNITED AC 2014; 204:777-92. [PMID: 24567358 PMCID: PMC3941050 DOI: 10.1083/jcb.201307055] [Citation(s) in RCA: 103] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Caveolae transduce mechanical stress into plasma membrane lipid alterations that disrupt Ras organization in an isoform-specific manner and modulate downstream signal transduction. The molecular mechanisms whereby caveolae exert control over cellular signaling have to date remained elusive. We have therefore explored the role caveolae play in modulating Ras signaling. Lipidomic and gene array analyses revealed that caveolin-1 (CAV1) deficiency results in altered cellular lipid composition, and plasma membrane (PM) phosphatidylserine distribution. These changes correlated with increased K-Ras expression and extensive isoform-specific perturbation of Ras spatial organization: in CAV1-deficient cells K-RasG12V nanoclustering and MAPK activation were enhanced, whereas GTP-dependent lateral segregation of H-Ras was abolished resulting in compromised signal output from H-RasG12V nanoclusters. These changes in Ras nanoclustering were phenocopied by the down-regulation of Cavin1, another crucial caveolar structural component, and by acute loss of caveolae in response to increased osmotic pressure. Thus, we postulate that caveolae remotely regulate Ras nanoclustering and signal transduction by controlling PM organization. Similarly, caveolae transduce mechanical stress into PM lipid alterations that, in turn, modulate Ras PM organization.
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Affiliation(s)
- Nicholas Ariotti
- The University of Queensland, Institute for Molecular Bioscience, Queensland 4072, Australia
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Signal integration by lipid-mediated spatial cross talk between Ras nanoclusters. Mol Cell Biol 2013; 34:862-76. [PMID: 24366544 DOI: 10.1128/mcb.01227-13] [Citation(s) in RCA: 106] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Lipid-anchored Ras GTPases form transient, spatially segregated nanoclusters on the plasma membrane that are essential for high-fidelity signal transmission. The lipid composition of Ras nanoclusters, however, has not previously been investigated. High-resolution spatial mapping shows that different Ras nanoclusters have distinct lipid compositions, indicating that Ras proteins engage in isoform-selective lipid sorting and accounting for different signal outputs from different Ras isoforms. Phosphatidylserine is a common constituent of all Ras nanoclusters but is only an obligate structural component of K-Ras nanoclusters. Segregation of K-Ras and H-Ras into spatially and compositionally distinct lipid assemblies is exquisitely sensitive to plasma membrane phosphatidylserine levels. Phosphatidylserine spatial organization is also modified by Ras nanocluster formation. In consequence, Ras nanoclusters engage in remote lipid-mediated communication, whereby activated H-Ras disrupts the assembly and operation of spatially segregated K-Ras nanoclusters. Computational modeling and experimentation reveal that complex effects of caveolin and cortical actin on Ras nanoclustering are similarly mediated through regulation of phosphatidylserine spatiotemporal dynamics. We conclude that phosphatidylserine maintains the lateral segregation of diverse lipid-based assemblies on the plasma membrane and that lateral connectivity between spatially remote lipid assemblies offers important previously unexplored opportunities for signal integration and signal processing.
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Zhou Y, Maxwell KN, Sezgin E, Lu M, Liang H, Hancock JF, Dial EJ, Lichtenberger LM, Levental I. Bile acids modulate signaling by functional perturbation of plasma membrane domains. J Biol Chem 2013; 288:35660-70. [PMID: 24165125 DOI: 10.1074/jbc.m113.519116] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Eukaryotic cell membranes are organized into functional lipid and protein domains, the most widely studied being membrane rafts. Although rafts have been associated with numerous plasma membrane functions, the mechanisms by which these domains themselves are regulated remain undefined. Bile acids (BAs), whose primary function is the solubilization of dietary lipids for digestion and absorption, can affect cells by interacting directly with membranes. To investigate whether these interactions affected domain organization in biological membranes, we assayed the effects of BAs on biomimetic synthetic liposomes, isolated plasma membranes, and live cells. At cytotoxic concentrations, BAs dissolved synthetic and cell-derived membranes and disrupted live cell plasma membranes, implicating plasma membrane damage as the mechanism for BA cellular toxicity. At subtoxic concentrations, BAs dramatically stabilized domain separation in Giant Plasma Membrane Vesicles without affecting protein partitioning between coexisting domains. Domain stabilization was the result of BA binding to and disordering the nonraft domain, thus promoting separation by enhancing domain immiscibility. Consistent with the physical changes observed in synthetic and isolated biological membranes, BAs reorganized intact cell membranes, as evaluated by the spatial distribution of membrane-anchored Ras isoforms. Nanoclustering of K-Ras, related to nonraft membrane domains, was enhanced in intact plasma membranes, whereas the organization of H-Ras was unaffected. BA-induced changes in Ras lateral segregation potentiated EGF-induced signaling through MAPK, confirming the ability of BAs to influence cell signal transduction by altering the physical properties of the plasma membrane. These observations suggest general, membrane-mediated mechanisms by which biological amphiphiles can produce their cellular effects.
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Affiliation(s)
- Yong Zhou
- From the Department of Integrative Biology and Pharmacology, the University of Texas Medical School, Houston, Texas 77030 and
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The shape/morphology balance: a study of stealth liposomes via fractal analysis and drug encapsulation. Pharm Res 2013; 30:2385-95. [PMID: 23743657 DOI: 10.1007/s11095-013-1082-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Accepted: 05/12/2013] [Indexed: 10/26/2022]
Abstract
PURPOSE Fractal analysis was used as a tool in order to study the morphological characteristics of PEGylated liposomes. We report on the morphological characteristics of stealth liposomes composed of DPPC and DPPE-PEG 3000 in two dispersion media using fractal analysis. METHODS Light scattering techniques were used in order to elucidate the size, the morphology and the surface charge of PEGylated liposomes as a function of PEGylated lipid concentration and temperature. Fluorescence spectroscopy studies revealed a microenvironment of low polarity inside the liposomal membranes. RESULTS All formulations were found to retain their physicochemical characteristics for at least 3 weeks. The hydrodynamic radii (Rh) of stealth liposomes were stable in the process of heating up to 50°C; while the fractal dimension values (df) which correspond to their morphology, have been changed during heating. Hence, these results are a first indication of the presence of a heterogeneous microdomain structure of the stealth liposomal system. The amphiphilic drug indomethacin (IND) was successfully encapsulated within the liposomes and led to an increased size of stealth liposomes, while the morphology of liposomal vectors changed significantly at the highest molar ratio of PEGylated lipid. CONCLUSIONS We can state that this approach can promote a new analytical concept based on the morphological characteristics and quantify the shape of drug carriers complementary to that of the conventional analytical techniques.
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Abstract
Ras proteins on the plasma membrane are laterally segregated into transient nanoclusters that are essential for high-fidelity signal transmission by the Ras/MAPK cascade. The dynamics of Ras nanocluster assembly and disassembly control MAPK signal output. BRaf inhibitors paradoxically activate CRaf and MAPK signaling in Ras-transformed cells. In our recent study, we showed that BRaf inhibition significantly enhances nanoclustering of oncogenic K- and N-Ras, but not H-Ras by increasing the frequency of Ras nanocluster formation. This disrupted spatiotemporal dynamics of Ras nanocluster fully accounts for the observed effects of Raf inhibitors on Ras signal transmission. Here together with other studies, we propose that the dynamics of Ras nanoclusters may represent a novel target for future therapeutic intervention.
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Affiliation(s)
- Kwang-Jin Cho
- Department of Integrative Biology and Pharmacology, The University of Texas Medical School, Houston, Houston, TX, USA
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Fendiline inhibits K-Ras plasma membrane localization and blocks K-Ras signal transmission. Mol Cell Biol 2012; 33:237-51. [PMID: 23129805 DOI: 10.1128/mcb.00884-12] [Citation(s) in RCA: 82] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Ras proteins regulate signaling pathways important for cell growth, differentiation, and survival. Oncogenic mutant Ras proteins are commonly expressed in human tumors, with mutations of the K-Ras isoform being most prevalent. To be active, K-Ras must undergo posttranslational processing and associate with the plasma membrane. We therefore devised a high-content screening assay to search for inhibitors of K-Ras plasma membrane association. Using this assay, we identified fendiline, an L-type calcium channel blocker, as a specific inhibitor of K-Ras plasma membrane targeting with no detectable effect on the localization of H- and N-Ras. Other classes of L-type calcium channel blockers did not mislocalize K-Ras, suggesting a mechanism that is unrelated to calcium channel blockade. Fendiline did not inhibit K-Ras posttranslational processing but significantly reduced nanoclustering of K-Ras and redistributed K-Ras from the plasma membrane to the endoplasmic reticulum (ER), Golgi apparatus, endosomes, and cytosol. Fendiline significantly inhibited signaling downstream of constitutively active K-Ras and endogenous K-Ras signaling in cells transformed by oncogenic H-Ras. Consistent with these effects, fendiline blocked the proliferation of pancreatic, colon, lung, and endometrial cancer cell lines expressing oncogenic mutant K-Ras. Taken together, these results suggest that inhibitors of K-Ras plasma membrane localization may have utility as novel K-Ras-specific anticancer therapeutics.
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