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Concurrent Compression of Phospholipid Membranes by Calcium and Cholesterol

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, ORCID}
Source Title	Langmuir. - : American Chemical Society - ISSN 0743-7463 Roč. 35, č. 35 (2019), s. 11358-11368
Number 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

Number of the records: 1