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Hong Z, Liu T, Wan L, Fa P, Kumar P, Cao Y, Prasad CB, Qiu Z, Joseph L, Hongbing W, Li Z, Wang QE, Guo P, Guo D, Yilmaz AS, Lu L, Papandreou I, Jacob NK, Yan C, Zhang X, She QB, Ma Z, Zhang J. Targeting Squalene Epoxidase Interrupts Homologous Recombination via the ER Stress Response and Promotes Radiotherapy Efficacy. Cancer Res 2022; 82:1298-1312. [PMID: 35045984 PMCID: PMC8983553 DOI: 10.1158/0008-5472.can-21-2229] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 11/03/2021] [Accepted: 01/10/2022] [Indexed: 11/16/2022]
Abstract
Over 50% of all patients with cancer are treated with radiotherapy. However, radiotherapy is often insufficient as a monotherapy and requires a nontoxic radiosensitizer. Squalene epoxidase (SQLE) controls cholesterol biosynthesis by converting squalene to 2,3-oxidosqualene. Given that SQLE is frequently overexpressed in human cancer, this study investigated the importance of SQLE in breast cancer and non-small cell lung cancer (NSCLC), two cancers often treated with radiotherapy. SQLE-positive IHC staining was observed in 68% of breast cancer and 56% of NSCLC specimens versus 15% and 25% in normal breast and lung tissue, respectively. Importantly, SQLE expression was an independent predictor of poor prognosis, and pharmacologic inhibition of SQLE enhanced breast and lung cancer cell radiosensitivity. In addition, SQLE inhibition enhanced sensitivity to PARP inhibition. Inhibition of SQLE interrupted homologous recombination by suppressing ataxia-telangiectasia mutated (ATM) activity via the translational upregulation of wild-type p53-induced phosphatase (WIP1), regardless of the p53 status. SQLE inhibition and subsequent squalene accumulation promoted this upregulation by triggering the endoplasmic reticulum (ER) stress response. Collectively, these results identify a novel tumor-specific radiosensitizer by revealing unrecognized cross-talk between squalene metabolites, ER stress, and the DNA damage response. Although SQLE inhibitors have been used as antifungal agents in the clinic, they have not yet been used as antitumor agents. Repurposing existing SQLE-inhibiting drugs may provide new cancer treatments. SIGNIFICANCE Squalene epoxidase inhibitors are novel tumor-specific radiosensitizers that promote ER stress and suppress homologous recombination, providing a new potential therapeutic approach to enhance radiotherapy efficacy.
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Affiliation(s)
- Zhipeng Hong
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
- Department of Breast Surgery, Affiliated Quanzhou First Hospital of Fujian Medical University, Quanzhou, Fujian, 362000, P.R. China
| | - Tao Liu
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Lingfeng Wan
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Pengyan Fa
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Pankaj Kumar
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Yanan Cao
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, 40506, USA
| | - Chandra Bhushan Prasad
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Zhaojun Qiu
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Liu Joseph
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Wang Hongbing
- Department of Pharmaceutical Sciences, University of Maryland School of Pharmacy, Baltimore, Maryland, USA
| | - Zaibo Li
- Department of Pathology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Qi-En Wang
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Peixuan Guo
- Center for RNA Nanobiotechnology and Nanomedicine, The Ohio State University, Columbus, OH, USA
| | - Deliang Guo
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Ayse Selen Yilmaz
- Department of Biomedical Informatics, College of Medicine, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, USA
| | - Lanchun Lu
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Ioanna Papandreou
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Naduparambil K Jacob
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
| | - Chunhong Yan
- Georgia Cancer Center, Augusta University, Augusta, GA, USA
| | - Xiaoli Zhang
- Department of Biomedical Informatics, College of Medicine, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, USA
| | - Qing-Bai She
- Department of Pharmacology and Nutritional Sciences, University of Kentucky College of Medicine, Lexington, KY, 40506, USA
| | - Zhefu Ma
- Department Breast Surgery and Plastic Surgery, Cancer Hospital of China Medical University, 44 Xiaoheyan Road, Dadong District, Shenyang, 110042, China
- Department Breast & Thyroid Surgery, The First Affiliated Hospital, Sun Yat-sen University, No.58 of Zhongshan 2nd Road, Yuexiu District, Guangzhou, 510080, China
| | - Junran Zhang
- Department of Radiation Oncology, The Ohio State University James Comprehensive Cancer Center and College of Medicine, OH, 43210, USA
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2
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Toopkanloo SP, Tan TB, Abas F, Azam M, Nehdi IA, Tan CP. Improving Vesicular Integrity and Antioxidant Activity of Novel Mixed Soy Lecithin-Based Liposomes Containing Squalene and Their Stability against UV Light. Molecules 2020; 25:E5873. [PMID: 33322600 PMCID: PMC7764204 DOI: 10.3390/molecules25245873] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/08/2020] [Accepted: 12/09/2020] [Indexed: 11/18/2022] Open
Abstract
In order to improve the membrane lipophilicity and the affinity towards the environment of lipid bilayers, squalene (SQ) could be conjugated to phospholipids in the formation of liposomes. The effect of membrane composition and concentrations on the degradation of liposomes prepared via the extrusion method was investigated. Liposomes were prepared using a mixture of SQ, cholesterol (CH) and Tween80 (TW80). Based on the optimal conditions, liposome batches were prepared in the absence and presence of SQ. Their physicochemical and stability behavior were evaluated as a function of liposome constituent. From the optimization study, the liposomal formulation containing 5% (w/w) mixed soy lecithin (ML), 0.5% (w/w) SQ, 0.3% (w/w) CH and 0.75% (w/w) TW80 had optimal physicochemical properties and displayed a unilamellar structure. Liposome prepared using the optimal formulation had a low particle size (158.31 ± 2.96 nm) and acceptable %increase in the particle size (15.09% ± 3.76%) and %trolox equivalent antioxidant capacity (%TEAC) loss (35.69% ± 0.72%) against UV light treatment (280-320 nm) for 6 h. The interesting outcome of this research was the association of naturally occurring substance SQ for size reduction without the extra input of energy or mechanical procedures, and improvement of vesicle stability and antioxidant activity of ML-based liposome. This study also demonstrated that the presence of SQ in the membrane might increase the acyl chain dynamics and decrease the viscosity of the dispersion, thereby limiting long-term stability of the liposome.
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Affiliation(s)
- Sahar Pakbaten Toopkanloo
- Department of Food Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia;
| | - Tai Boon Tan
- Department of Food Service and Management, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM, Serdang 43400, Selangor, Malaysia;
| | - Faridah Abas
- Department of Food Science, Faculty of Food Science and Technology, Universiti Putra Malaysia, UPM, Serdang 43400, Selangor, Malaysia;
| | - Mohammad Azam
- Chemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; (M.A.); (I.A.N.)
| | - Imededdine Arbi Nehdi
- Chemistry Department, College of Science, King Saud University, P.O. Box 2455, Riyadh 11451, Saudi Arabia; (M.A.); (I.A.N.)
- Chemistry Department, El Manar Preparatory Institute for Engineering Studies, Tunis El Manar University, P.O. Box 244, Tunis 2092, Tunisia
| | - Chin Ping Tan
- Department of Food Technology, Faculty of Food Science and Technology, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia;
- Laboratory of Processing and Product Development, Institute of Plantation Studies, Universiti Putra Malaysia, Serdang 43400, Selangor, Malaysia
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3
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Csáky Z, Garaiová M, Kodedová M, Valachovič M, Sychrová H, Hapala I. Squalene lipotoxicity in a lipid droplet‐less yeast mutant is linked to plasma membrane dysfunction. Yeast 2020; 37:45-62. [DOI: 10.1002/yea.3454] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 12/02/2019] [Accepted: 12/07/2019] [Indexed: 12/13/2022] Open
Affiliation(s)
- Zsófia Csáky
- Department of Membrane Biochemistry Institute of Animal Biochemistry and Genetics, Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| | - Martina Garaiová
- Department of Membrane Biochemistry Institute of Animal Biochemistry and Genetics, Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| | - Marie Kodedová
- Department of Membrane Transport, Division BIOCEV Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Martin Valachovič
- Department of Membrane Biochemistry Institute of Animal Biochemistry and Genetics, Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
| | - Hana Sychrová
- Department of Membrane Transport, Division BIOCEV Institute of Physiology of the Czech Academy of Sciences Prague Czech Republic
| | - Ivan Hapala
- Department of Membrane Biochemistry Institute of Animal Biochemistry and Genetics, Centre of Biosciences of the Slovak Academy of Sciences Bratislava Slovakia
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Salvador-Castell M, Brooks NJ, Peters J, Oger P. Induction of non-lamellar phases in archaeal lipids at high temperature and high hydrostatic pressure by apolar polyisoprenoids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2019; 1862:183130. [PMID: 31734311 DOI: 10.1016/j.bbamem.2019.183130] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 11/11/2019] [Accepted: 11/12/2019] [Indexed: 12/01/2022]
Abstract
It is now well established that cell membranes are much more than a barrier that separate the cytoplasm from the outside world. Regarding membrane's lipids and their self-assembling, the system is highly complex, for example, the cell membrane needs to adopt different curvatures to be functional. This is possible thanks to the presence of non-lamellar-forming lipids, which tend to curve the membrane. Here, we present the effect of squalane, an apolar isoprenoid molecule, on an archaea-like lipid membrane. The presence of this molecule provokes negative membrane curvature and forces lipids to self-assemble under inverted cubic and inverted hexagonal phases. Such non-lamellar phases are highly stable under a broad range of external extreme conditions, e.g. temperatures and high hydrostatic pressures, confirming that such apolar lipids could be included in the architecture of membranes arising from cells living under extreme environments.
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Affiliation(s)
| | - Nicholas J Brooks
- Imperial College London, South Kensington Campus, London SW7 2AZ, England, United Kingdom of Great Britain and Northern Ireland
| | - Judith Peters
- Université Grenoble Alpes, LiPhy, CNRS, 38000 Grenoble, France; Institut Laue Langevin, 38000 Grenoble, France
| | - Philippe Oger
- Université de Lyon, INSA de Lyon, CNRS, UMR 5240, 69211 Villeurbanne, France.
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5
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Salvador-Castell M, Tourte M, Oger PM. In Search for the Membrane Regulators of Archaea. Int J Mol Sci 2019; 20:E4434. [PMID: 31505830 PMCID: PMC6770870 DOI: 10.3390/ijms20184434] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 09/04/2019] [Accepted: 09/06/2019] [Indexed: 11/23/2022] Open
Abstract
Membrane regulators such as sterols and hopanoids play a major role in the physiological and physicochemical adaptation of the different plasmic membranes in Eukarya and Bacteria. They are key to the functionalization and the spatialization of the membrane, and therefore indispensable for the cell cycle. No archaeon has been found to be able to synthesize sterols or hopanoids to date. They also lack homologs of the genes responsible for the synthesis of these membrane regulators. Due to their divergent membrane lipid composition, the question whether archaea require membrane regulators, and if so, what is their nature, remains open. In this review, we review evidence for the existence of membrane regulators in Archaea, and propose tentative location and biological functions. It is likely that no membrane regulator is shared by all archaea, but that they may use different polyterpenes, such as carotenoids, polyprenols, quinones and apolar polyisoprenoids, in response to specific stressors or physiological needs.
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Affiliation(s)
- Marta Salvador-Castell
- Université de Lyon, CNRS, UMR 5240, F-69621 Villeurbanne, France.
- Université de Lyon, INSA de Lyon, UMR 5240, F-69621 Villeurbanne, France.
| | - Maxime Tourte
- Université de Lyon, CNRS, UMR 5240, F-69621 Villeurbanne, France.
- Université de Lyon, INSA de Lyon, UMR 5240, F-69621 Villeurbanne, France.
| | - Philippe M Oger
- Université de Lyon, CNRS, UMR 5240, F-69621 Villeurbanne, France.
- Université de Lyon, INSA de Lyon, UMR 5240, F-69621 Villeurbanne, France.
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6
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Mingeot-Leclercq MP, Décout JL. Bacterial lipid membranes as promising targets to fight antimicrobial resistance, molecular foundations and illustration through the renewal of aminoglycoside antibiotics and emergence of amphiphilic aminoglycosides. MEDCHEMCOMM 2016. [DOI: 10.1039/c5md00503e] [Citation(s) in RCA: 97] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Membrane anionic lipids as attractive targets in the design of amphiphilic antibacterial drugs active against resistant bacteria: molecular foundations and examples.
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Affiliation(s)
- Marie-Paule Mingeot-Leclercq
- Louvain Drug Research Institute
- Université catholique de Louvain
- Unité de Pharmacologie Cellulaire et Moléculaire
- Brussels
- Belgium
| | - Jean-Luc Décout
- Département de Pharmacochimie Moléculaire
- Université Grenoble Alpes/CNRS
- UMR 5063
- ICMG FR 2607
- F-38041 Grenoble
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7
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8
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Spanova M, Zweytick D, Lohner K, Klug L, Leitner E, Hermetter A, Daum G. Influence of squalene on lipid particle/droplet and membrane organization in the yeast Saccharomyces cerevisiae. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:647-53. [PMID: 22342273 PMCID: PMC3790963 DOI: 10.1016/j.bbalip.2012.01.015] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2011] [Revised: 01/12/2012] [Accepted: 01/30/2012] [Indexed: 02/02/2023]
Abstract
In a previous study (Spanova et al., 2010, J. Biol. Chem., 285, 6127–6133) we demonstrated that squalene, an intermediate of sterol biosynthesis, accumulates in yeast strains bearing a deletion of the HEM1 gene. In such strains, the vast majority of squalene is stored in lipid particles/droplets together with triacylglycerols and steryl esters. In mutants lacking the ability to form lipid particles, however, substantial amounts of squalene accumulate in organelle membranes. In the present study, we investigated the effect of squalene on biophysical properties of lipid particles and biological membranes and compared these results to artificial membranes. Our experiments showed that squalene together with triacylglycerols forms the fluid core of lipid particles surrounded by only a few steryl ester shells which transform into a fluid phase below growth temperature. In the hem1∆ deletion mutant a slight disordering effect on steryl esters was observed indicated by loss of the high temperature transition. Also in biological membranes from the hem1∆ mutant strain the effect of squalene per se is difficult to pinpoint because multiple effects such as levels of sterols and unsaturated fatty acids contribute to physical membrane properties. Fluorescence spectroscopic studies using endoplasmic reticulum, plasma membrane and artificial membranes revealed that it is not the absolute squalene level in membranes but rather the squalene to sterol ratio which mainly affects membrane fluidity/rigidity. In a fluid membrane environment squalene induces rigidity of the membrane, whereas in rigid membranes there is almost no additive effect of squalene. In summary, our results demonstrate that squalene (i) can be well accommodated in yeast lipid particles and organelle membranes without causing deleterious effects; and (ii) although not being a typical membrane lipid may be regarded as a mild modulator of biophysical membrane properties.
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Affiliation(s)
- Miroslava Spanova
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Dagmar Zweytick
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Graz, Austria
| | - Karl Lohner
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Graz, Austria
| | - Lisa Klug
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Erich Leitner
- Institute of Analytical Chemistry and Food Technology, Graz University of Technology, Austria
| | - Albin Hermetter
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
| | - Günther Daum
- Institute of Biochemistry, Graz University of Technology, Graz, Austria
- Corresponding author at: Institute of Biochemistry, Graz University of Technology, Petersgasse 12/II, A-8010 Graz, Austria. Tel.: + 43 316 873 6462; fax: + 43 316 873 6952.
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9
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Quinn PJ. The structure of complexes between phosphatidylethanolamine and glucosylceramide: A matrix for membrane rafts. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:2894-904. [DOI: 10.1016/j.bbamem.2011.08.033] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2011] [Revised: 08/22/2011] [Accepted: 08/30/2011] [Indexed: 12/12/2022]
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10
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Spanova M, Daum G. Squalene - biochemistry, molecular biology, process biotechnology, and applications. EUR J LIPID SCI TECH 2011. [DOI: 10.1002/ejlt.201100203] [Citation(s) in RCA: 155] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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11
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Mondal Roy S, Sarkar M. Membrane fusion induced by small molecules and ions. J Lipids 2011; 2011:528784. [PMID: 21660306 PMCID: PMC3108104 DOI: 10.1155/2011/528784] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/28/2011] [Accepted: 02/25/2011] [Indexed: 01/11/2023] Open
Abstract
Membrane fusion is a key event in many biological processes. These processes are controlled by various fusogenic agents of which proteins and peptides from the principal group. The fusion process is characterized by three major steps, namely, inter membrane contact, lipid mixing forming the intermediate step, pore opening and finally mixing of inner contents of the cells/vesicles. These steps are governed by energy barriers, which need to be overcome to complete fusion. Structural reorganization of big molecules like proteins/peptides, supplies the required driving force to overcome the energy barrier of the different intermediate steps. Small molecules/ions do not share this advantage. Hence fusion induced by small molecules/ions is expected to be different from that induced by proteins/peptides. Although several reviews exist on membrane fusion, no recent review is devoted solely to small moleculs/ions induced membrane fusion. Here we intend to present, how a variety of small molecules/ions act as independent fusogens. The detailed mechanism of some are well understood but for many it is still an unanswered question. Clearer understanding of how a particular small molecule can control fusion will open up a vista to use these moleucles instead of proteins/peptides to induce fusion both in vivo and in vitro fusion processes.
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Affiliation(s)
- Sutapa Mondal Roy
- Chemical Sciences Division, Saha Institute of Nuclear Physics, Sector 1, Block AF, Bidhannagar, Kolkata 700064, India
| | - Munna Sarkar
- Chemical Sciences Division, Saha Institute of Nuclear Physics, Sector 1, Block AF, Bidhannagar, Kolkata 700064, India
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12
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Spanova M, Czabany T, Zellnig G, Leitner E, Hapala I, Daum G. Effect of lipid particle biogenesis on the subcellular distribution of squalene in the yeast Saccharomyces cerevisiae. J Biol Chem 2009; 285:6127-33. [PMID: 20032462 DOI: 10.1074/jbc.m109.074229] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Squalene belongs to the group of isoprenoids and is a precursor for the synthesis of sterols, steroids, and ubiquinones. In the yeast Saccharomyces cerevisiae, the amount of squalene can be increased by variation of growth conditions or by genetic manipulation. In this report, we show that a hem1Delta mutant accumulated a large amount of squalene, which was stored almost exclusively in cytoplasmic lipid particles/droplets. Interestingly, a strain bearing a hem1Delta deletion in a dga1Delta lro1Delta are1Delta are2Delta quadruple mutant background (QMhem1Delta), which is devoid of the classical storage lipids, triacylglycerols and steryl esters, and lacks lipid particles, accumulated squalene at similar amounts as the hem1Delta mutant in a wild type background. In QMhem1Delta, however, increased amounts of squalene were found in cellular membranes, especially in microsomes. The fact that QMhem1Delta did not form lipid particles indicated that accumulation of squalene solely was not sufficient to initiate proliferation of lipid particles. Most importantly, these results also demonstrated that (i) squalene was not lipotoxic under the conditions tested, and (ii) organelle membranes in yeast can accommodate relatively large quantities of this non-polar lipid without compromising cellular functions. In summary, localization of squalene as described here can be regarded as an unconventional example of non-polar lipid storage in cellular membranes.
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Affiliation(s)
- Miroslava Spanova
- Institute of Biochemistry, Graz University of Technology, Petersgasse 12/II, A-8010 Graz, Austria
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13
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Lohner K, Prossnigg F. Biological activity and structural aspects of PGLa interaction with membrane mimetic systems. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1788:1656-66. [DOI: 10.1016/j.bbamem.2009.05.012] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2009] [Revised: 05/21/2009] [Accepted: 05/22/2009] [Indexed: 10/20/2022]
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14
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Wang X, Mansourian AR, Quinn PJ. The effect of dolichol on the structure and phase behaviour of phospholipid model membranes. Mol Membr Biol 2009; 25:547-56. [DOI: 10.1080/09687680802520684] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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15
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Glück R, Walti E. Are Anti-Phosphoupid Antibodies to be Expected after Proteoliposomal Hepatitis A Vaccination? J Liposome Res 2008. [DOI: 10.3109/08982109609031125] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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16
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Rappolt M, Hodzic A, Sartori B, Ollivon M, Laggner P. Conformational and hydrational properties during the L(beta)- to L(alpha)- and L(alpha)- to H(II)-phase transition in phosphatidylethanolamine. Chem Phys Lipids 2008; 154:46-55. [PMID: 18339315 DOI: 10.1016/j.chemphyslip.2008.02.006] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2007] [Revised: 01/08/2008] [Accepted: 02/17/2008] [Indexed: 10/22/2022]
Abstract
Differential scanning calorimetry (DSC) measurements have been carried out simultaneously with small- and wide-angle X-ray scattering recordings on liposomal dispersions of stearoyl-oleoyl-phosphatidylethanolamine (PE) in a temperature range from 20 to 80 degrees C. The main transition temperature, T(m), was determined at 30.9 degrees C with an enthalpy of 28.5 kJ/mol and the lamellar-to-inverse hexagonal phase transition temperature, T(hex), at 61.6 degrees C with an enthalpy of 3.8 kJ/mol. Additionally highly resolved small angle X-ray diffraction experiments performed at equilibrium conditions allowed a reliable decomposition of the lattice spacings into hydrophobic and hydrophilic structure elements as well as the determination of the lipid interface area of the lamellar gel-phase (L(beta)), the fluid lamellar phase (L(alpha)) and of the inverse hexagonal phase (H(II)). The rearrangement of the lipid matrix and the coincident change of free water per lipid is illustrated for both transitions. Last, possible transition mechanisms are discussed on a molecular level.
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Affiliation(s)
- Michael Rappolt
- Institute of Biophysics and Nanosystems Research, Austrian Academy of Sciences, Graz, Austria.
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17
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Lohner K, Sevcsik E, Pabst G. Chapter Five Liposome-Based Biomembrane Mimetic Systems: Implications for Lipid–Peptide Interactions. ADVANCES IN PLANAR LIPID BILAYERS AND LIPOSOMES 2008. [DOI: 10.1016/s1554-4516(07)06005-x] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
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18
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Effects of contaminants on biological model membranes: The advantage of the ASAXS method for the study of the location of copper ions and dihalogenated phenol molecules. Colloids Surf A Physicochem Eng Asp 2005. [DOI: 10.1016/j.colsurfa.2005.02.041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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19
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Abstract
There is a growing awareness of the utility of lipid phase behavior data in studies of membrane-related phenomena. Such miscibility information is commonly reported in the form of temperature-composition (T-C) phase diagrams. The current index is a conduit to the relevant literature. It lists lipid phase diagrams, their components and conditions of measurement, and complete bibliographic information. The main focus of the index is on lipids of membrane origin where water is the dispersing medium. However, it also includes records on acylglycerols, fatty acids, cationic lipids, and detergent-containing systems. The miscibility of synthetic and natural lipids with other lipids, with water, and with biomolecules (proteins, nucleic acids, carbohydrates, etc.) and non-biological materials (drugs, anesthetics, organic solvents, etc.) is within the purview of the index. There are 2188 phase diagram records in the index, the bulk (81%) of which refers to binary (two-component) T-C phase diagrams. The remainder is made up of more complex (ternary, quaternary) systems, pressure-T phase diagrams, and other more exotic miscibility studies. The index covers the period from 1965 through to July, 2001.
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Affiliation(s)
- Rumiana Koynova
- Biochemistry, Biophysics, Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA
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20
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Abstract
An enzyme-linked immunosorbent assay (ELISA) utilizing antigen coated on hydrophobic polyvinyldiene fluoride (PVDF) membranes is described for detecting antibodies that bind to squalene (SQE). Because of the prior lack of availability of validated antibodies to SQE, positive controls for the assay were made by immunization with formulations containing SQE to create monoclonal antibodies (mAbs) that reacted with SQE. Among eight immunogens tested, only two induced detectable murine antibodies to SQE: liposomes containing dimyristoyl phosphatidylcholine, dimyristoyl phosphatidylglycerol, 71% SQE, and lipid A [L(71% SQE+LA)], and, to a much lesser extent, an oil-in-water emulsion containing SQE, Tween 80, Span 85, and lipid A. In each case, lipid A served as an adjuvant, but neither SQE alone, SQE mixed with lipid A, liposomes containing 43% SQE and lipid A, nor several other emulsions containing both SQE and lipid A, induced antibodies that reacted with SQE. Monoclonal antibodies produced after immunizing mice with [L(71% SQE+LA)] served as positive controls for developing the ELISA. Monoclonal antibodies were produced that either recognized SQE alone but did not recognize squalane (SQA, the hydrogenated form of SQE), or that recognized both SQE and SQA. As found previously with other liposomal lipid antigens, liposomes containing lipid A also induced antibodies that reacted with the liposomal phospholipids. However, mAbs were also identified that reacted with SQE on PVDF membranes, but did not recognize either SQA or liposomal phospholipid. The polyclonal antiserum produced by immunizing mice with [L(71% SQE+LA)] therefore contained a mixed population of antibody specificities and, as expected, the ELISA of polyclonal antiserum with PVDF membranes detected antibodies both to SQE and SQA. We conclude that SQE is a weak antigen, but that antibodies that specifically bind to SQE can be readily induced by immunization with [L(71% SQE+LA)] and detected by ELISA with PVDF membranes coated with SQE.
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Affiliation(s)
- G R Matyas
- Department of Membrane Biochemistry, Walter Reed Army Institute of Research, Silver Spring, MD 20910-7500, USA.
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21
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Giusto NM, Pasquaré SJ, Salvador GA, Castagnet PI, Roque ME, Ilincheta de Boschero MG. Lipid metabolism in vertebrate retinal rod outer segments. Prog Lipid Res 2000; 39:315-91. [PMID: 10856601 DOI: 10.1016/s0163-7827(00)00009-6] [Citation(s) in RCA: 78] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Affiliation(s)
- N M Giusto
- Instituto de Investigaciones Bioquímicas, Universidad Nacional del Sur and Consejo Nacional de Investigaciones Científicas y Técnicas, CC 857, B 8000 FWB, Bahia Blanca, Argentina.
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22
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El Jastimi R, Lafleur M. Nisin promotes the formation of non-lamellar inverted phases in unsaturated phosphatidylethanolamines. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1418:97-105. [PMID: 10209214 DOI: 10.1016/s0005-2736(99)00027-9] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
Nisin, a peptide used as a food preservative, is shown, by 31P-nuclear magnetic resonance and infrared spectroscopy, to perturb the structure of membranes formed of unsaturated phosphatidylethanolamine (PE) and to induce the formation of inverted non-lamellar phases. In the case of dioleoyl-sn-glycero-3-phosphatidylethanolamine (DOPE), nisin promotes the formation of inverted hexagonal phase. Similarly, the peptide induces the formation of an isotropic phase, most likely a cubic phase, with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphatidylethanolamine (POPE). It is proposed that the insertion of the peptide in the bilayer shifts the amphiphilic balance by increasing the hydrophobic contribution and is at the origin of the changes in the polymorphic propensities of PE. This is supported by the fact that the presence of cholesterol in the PE bilayer inhibits the power of nisin to perturb the membrane structure, most likely because the peptide insertion is difficult in the fluid ordered phase. This finding provides insight into possible antibacterial mechanisms of nisin.
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Affiliation(s)
- R El Jastimi
- Department of Chemistry, C.P. 6128, Succ. Centre Ville, Université de Montréal, Montréal, Qué. H3C 3J7, Canada
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23
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Takahashi H, Watanabe M, Quinn PJ, Kato S, Murayama S, Ohki K, Hatta I. Effects of diacylglycerol on the structure and phase behaviour of non-bilayer forming phospholipid. Biophys Chem 1999; 77:37-48. [PMID: 17027468 DOI: 10.1016/s0301-4622(99)00005-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/1998] [Revised: 12/31/1998] [Accepted: 12/31/1998] [Indexed: 10/17/2022]
Abstract
The phase behaviour of mixed aqueous dispersions of the monomethyl derivative of dioleoylphosphatidylethanolamine and dipalmitoylglycerol has been characterised by X-ray diffraction, differential scanning calorimetry and freeze-fracture electron microscopy for mixtures containing dipalmitoylglycerol in the concentration range 0-20 mol%. Dispersions prepared at temperatures where the phospholipid exhibits a liquid-crystalline lamellar phase show that dipalmitoylglycerol is completely phase separated into aggregates of stable crystal phase (beta'-phase). Heating mixed dispersions results in transformation of lamellar into hexagonal-II structure commencing at approximately 45 degrees C. This temperature coincides with a disappearance of beta'-phase of DPG which becomes incorporated into hexagonal-II phase. The pure phospholipid is transformed upon cooling from hexagonal-II into characteristic cubic phases; the formation of cubic phase is prevented by the presence of dipalmitoylglycerol and mixed dispersions initially form a lamellar liquid-crystalline phase in which the lipids are phase separated. The X-ray and thermal data suggest that relatively small domains of metastable crystal phase (alpha-phase) of DPG form initially on cooling and these subsequently coalesce and transform to beta'-phase.
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Affiliation(s)
- H Takahashi
- Department of Applied Physics, Graduate School of Engineering, Nagoya University, Nagoya 464-8603, Japan.
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24
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Abstract
Herein, studies concerning the biosynthesis, intracellular transport and utilization of isoprenoid lipids in vertebrate retinas are reviewed, with particular regard to rod photoreceptor cells and the assembly of rod outer segment (ROS) disk membranes. Initial in vitro studies with bovine retinas showed that [3H]mevalonate is metabolized primarily to squalene and 'methylated' sterols, rather than to cholesterol. Subsequently, similar results were obtained with frog retinas using [3H]acetate as a precursor, and the absolute rate of the sterol pathway was determined in vitro with 3H2O. With the aid of vesicular transport inhibitors, energy poisons, and reduced temperature, it was demonstrated that lipid and protein trafficking mechanisms in the rod cell are separate and independent from one another. In vivo, the majority of newly synthesized squalene in the frog retina is not metabolized to sterols; rather, it is transported to the ROS, where it turns over in parallel with the disk membranes. The remaining squalene is converted slowly to cholesterol, much of which becomes incorporated into the ROS. In contrast, the in vivo metabolism of [3H]acetate to cholesterol in the rat retina is relatively efficient and rapid. However, in both frog and rat, retinal cholesterol turnover is slow (> 60 days), suggesting the existence of a retention mechanism that minimizes the need for de novo biosynthesis. The use of pharmacological approaches to assess the biological roles of isoprenoid lipids and protein prenylation in the retina and the mechanism of retinal cholesterol homeostasis are discussed.
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Affiliation(s)
- S J Fliesler
- Saint Louis University Eye Institute, Saint Louis University Health Sciences Center, MO 63104-1540, USA
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25
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Lewis RN, Mannock DA, Mcelhaney RN. Chapter 2 Membrane Lipid Molecular Structure and Polymorphism. CURRENT TOPICS IN MEMBRANES 1997. [DOI: 10.1016/s0070-2161(08)60206-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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26
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Lohner K. Is the high propensity of ethanolamine plasmalogens to form non-lamellar lipid structures manifested in the properties of biomembranes? Chem Phys Lipids 1996; 81:167-84. [PMID: 8810047 DOI: 10.1016/0009-3084(96)02580-7] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Plasmalogens are glycerophospholipids characterized by an alk-1'-enylether bond in position sn-1 and an acyl bond in position sn-2. These ubiquitous etherlipids exhibit a different molecular structure as compared to diacyl phospholipids. The most peculiar change is a perpendicular orientation of the sn-2 acyl chain at all segments to the membrane surface. This extended conformation results in an effectively longer aliphatic chain in plasmalogen than in the diacyl analog. Moreover, the lack of the carbonyl oxygen in position sn-1 affects the hydrophilicity of the headgroup and allows stronger intermolecular hydrogen-bonding between the headgroups of the lipid. These properties favour the formation of non-lamellar structures which are expressed in the high affinity of ethanolamine plasmalogen to adopt the inverse hexagonal phase. Such structures may be involved in membrane processes, either temporarily, like in membrane fusion or locally, e.g. to affect the activity of membrane-bound proteins. The predominant distribution of ethanolamine plasmalogens in some cellular membranes like nerve tissues or plasma membranes and their distinctly different properties in model membranes as compared to diacyl phospholipids impose the question, whether these differences are also manifested in the heterogeneous environment of biological membranes. The integration of biophysical studies and biochemical findings clearly indicated that the high propensity of ethanolamine plasmalogen to form non-lamellar structures is reflected in several physiological functions. So far it seems to be evident that ethanolamine plasmalogens play an important role in maintaining the balance between bilayer and non-lamellar phases which is crucial for proper cell function. Furthermore, they are the major phospholipid component of inverse hexagonal phase inclusions in native retina and are able to mediate membrane fusion as demonstrated between neurotransmitter vesicles and presynaptic membranes.
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Affiliation(s)
- K Lohner
- Institut für Biophysik und Röntgenstrukturforschung, Osterreichische Akademie der Wissenschaften, Graz, Austria.
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27
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28
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Takahashi H, Sinoda K, Hatta I. Effects of cholesterol on the lamellar and the inverted hexagonal phases of dielaidoylphosphatidylethanolamine. BIOCHIMICA ET BIOPHYSICA ACTA 1996; 1289:209-16. [PMID: 8600975 DOI: 10.1016/0304-4165(95)00170-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Effects of cholesterol on the lamellar and the inverted hexagonal (HII ) phases of dielaidoylphosphatidylethanolamine (DEPE) were studied by means of not only differential scanning calorimetry (DSC) but also simultaneous X-ray diffraction and DSC (XDDSC). XDDSC shows that structural changes are related to thermotropic events of the mixtures. Addition of cholesterol to DEPE induces to broaden the transition from the lamellar gel (L beta) to lamellar liquid-crystalline (L alpha) phase. In fact, in the broad transition region, a coexistence of two lamellar X-ray diffraction peaks of the L beta and L alpha phases take place. In samples containing above 30 mol% cholesterol, no peak at the L beta-L alpha phase transition was observed in the DSC thermogram. On the other hand, cholesterol causes biphasic effects on the L alpha-HII phase transition: At low cholesterol concentrations below 20 mol%, the incorporation of cholesterol reduces the transition temperature and at high cholesterol concentrations about 30 mol%, the transition temperature increases by addition of cholesterol. Based upon the results of X-ray diffraction, the thermal expansion coefficients of lattice spacings, i.e., the temperature dependence of lattice spacings, were calculated in each phase. Addition of cholesterol reduces the thermal expansion coefficients of the lamellar phases and, in contrast, increases that of the HII phase. From the above results it is suggested that cholesterol in cell membranes works in keeping the bilayer membrane nature notwithstanding the change of external conditions.
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Affiliation(s)
- H Takahashi
- Department of Applied Physics, Nagoya University, Japan
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29
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Kinnunen PK, Kõiv A, Lehtonen JY, Rytömaa M, Mustonen P. Lipid dynamics and peripheral interactions of proteins with membrane surfaces. Chem Phys Lipids 1994; 73:181-207. [PMID: 8001181 DOI: 10.1016/0009-3084(94)90181-3] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
A large body of evidence strongly indicates biomembranes to be organized into compositionally and functionally specialized domains, supramolecular assemblies, existing on different time and length scales. For these domains and intimate coupling between their chemical composition, physical state, organization, and functions has been postulated. One important constituent of biomembranes are peripheral proteins whose activity can be controlled by non-covalent binding to lipids. Importantly, the physical chemistry of the lipid interface allows for a rapid and reversible control of peripheral interactions. In this review examples are provided on how membrane lipid (i) composition (i.e., specific lipid structures), (ii) organization, and (iii) physical state can each regulate peripheral binding of proteins to the lipid surface. In addition, a novel and efficient mechanism for the control of the lipid surface association of peripheral proteins by [Ca2+], lipid composition, and phase state is proposed. The phase state is, in turn, also dependent on factors such as temperature, lateral packing, presence of ions, metabolites and drugs. Confining reactions to interfaces allows for facile and cooperative large scale integration and control of metabolic pathways due to mechanisms which are not possible in bulk systems.
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Affiliation(s)
- P K Kinnunen
- Department of Medical Chemistry, University of Helsinki, Finland
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