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Concurrent Compression of Phospholipid Membranes by Calcium and Cholesterol
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SYSNO ASEP 0517192 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Concurrent Compression of Phospholipid Membranes by Calcium and Cholesterol Author(s) Melcrová, Adéla (UFCH-W)
Pokorná, Šárka (UFCH-W) RID
Vošahlíková, Miroslava (FGU-C) RID, ORCID, SAI
Sýkora, Jan (UFCH-W) RID
Svoboda, Petr (FGU-C) RID, ORCID
Hof, Martin (UFCH-W) RID, ORCID
Cwiklik, Lukasz (UFCH-W) RID, ORCID
Jurkiewicz, Piotr (UFCH-W) RID, ORCIDSource Title Langmuir. - : American Chemical Society - ISSN 0743-7463
Roč. 35, č. 35 (2019), s. 11358-11368Number of pages 11 s. Language eng - English Country US - United States Keywords hek293 cells ; bilayer-membranes ; divalent-cations ; lipid-bilayers ; fusion protein ; binding ; hydration ; fluorescence ; dynamics ; sodium Subject RIV CF - Physical ; Theoretical Chemistry OECD category Physical chemistry Subject RIV - cooperation Institute of Physiology - Biochemistry R&D Projects GA17-05903S GA ČR - Czech Science Foundation (CSF) GA18-26751S GA ČR - Czech Science Foundation (CSF) Method of publishing Limited access Institutional support UFCH-W - RVO:61388955 ; FGU-C - RVO:67985823 UT WOS 000484644000015 EID SCOPUS 85071784813 DOI 10.1021/acs.langmuir.9b00477 Annotation Regulation of cell metabolism, membrane fusion, association of proteins with cellular membranes, and cellular signaling altogether would not be possible without Ca2+ ions. The distribution of calcium within the cell is uneven with the negatively charged inner leaflet of the plasma membrane being one of the primary targets of its accumulation. Therefore, we decided to map the influence of Ca2+ on the properties of lipid bilayers closely resembling natural lipid membranes. We combined fluorescence spectroscopy (analysis of time-resolved emission spectra of Laurdan probe and derived parameters: integrated relaxation time related to local lipid mobility, and total emission shift reflecting membrane polarity and hydration) with molecular dynamics simulations to determine the effect of the increasing CaCl2 concentration on model lipid membranes containing POPC, POPS, and cholesterol. On top of that, the impact of calcium on the plasma membranes isolated from HEK293 cells was investigated using the steady-state fluorescence of Laurdan. We found that calcium increases rigidity of all the model lipid membranes used, elevates their thickness, increases lipid packing and ordering, and impedes the local lipid mobility. All these effects were to a great extent similar to those elicited by cholesterol. However, the changes of the membrane properties induced by calcium and cholesterol seem largely independent from each other. At sufficiently high concentrations of calcium or cholesterol, the steric effects hindered a further alteration of membrane organization, i.e., the compressibility limit of membrane structures was reached. We found no indication for mutual interaction between Ca2+ and cholesterol, nor competition of Ca2+ ions and hydroxyl groups of cholesterol for binding to phospholipids. Fluorescence measurements indicated that Ca2+ adsorption decreases mobility within the carbonyl region of model bilayers more efficiently than monovalent ions do (Ca2+ >> Li+ > Na+ > K+ > Cs+). The effects of calcium ions were to a great extent mitigated in the plasma membranes isolated from HEK293 cells when compared to the model lipid membranes. Noticeably, the plasma membranes showed remarkably higher resistance toward rigidification induced by calcium ions even when compared with the model membranes containing cholesterol. Workplace J. Heyrovsky Institute of Physical Chemistry Contact Michaela Knapová, michaela.knapova@jh-inst.cas.cz, Tel.: 266 053 196 Year of Publishing 2020 Electronic address http://hdl.handle.net/11104/0302482
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