mapping-molecular-diffusion-plasma-membrane-multiple-target-tracing

Mapping Molecular Diffusion in the Plasma Membrane by Multiple-Target Tracing (MTT)

Our goal is to obtain a comprehensive description of molecular processes occurring at cellular membranes in different biological functions. We aim at ...

spot-variation-fluorescence-correlation-spectroscopy-for-analysis

Spot Variation Fluorescence Correlation Spectroscopy for Analysis of Molecular Diffusion at the Plasma Membrane of Living Cells

Dynamic biological processes in living cells, including those associated with plasma membrane organization, occur on various spatial and temporal scales, ...

Parc scientifique de Luminy

Aix-Marseille University

University of Wroclaw

Steady-state polarization-resolved fluorescence imaging is used to analyze the molecular orientational order behavior of rigidly labeled major histocompatibility complex class I (MHC I) proteins and lipid probes in cell membranes of living cells. These fluorescent probes report the orientational properties of proteins and their surrounding lipid environment. We present a statistical study of the molecular orientational order, modeled as the width of the angular distribution of the molecules, for the proteins in the cell endomembrane and plasma membrane, as well as for the lipid probes in the plasma membrane. We apply this methodology on cells after treatments affecting the actin and microtubule networks. We find in particular opposite orientational order changes of proteins and lipid probes in the plasma membrane as a response to the cytoskeleton disruption. This suggests that MHC I orientational order is governed by its interaction with the cytoskeleton, whereas the plasma membrane lipid order is governed by the local cell membrane morphology.

Probing orientational behavior of MHC class I protein and lipid probes in cell membranes by fluorescence polarization-resolved imaging.

Amphotericin B (AmB) belongs to a group of polyene antibiotics commonly used in the treatment of systemic mycotic infections. A widely accepted mechanism of action of AmB is based on the formation of an oligomeric pore structure within the plasma membrane (PM) by interaction with membrane sterols. Although AmB binds preferentially to ergosterol, it can also bind to cholesterol in the mammalian PM and cause severe cellular toxicity. The lipid content and its lateral organization at the cell PM appear to be significant for AmB binding. Several ATP-binding cassette (ABC) transporters, including ABCA1, play a crucial role in lipid translocation, cholesterol redistribution and efflux. Here, we demonstrate that cells expressing ABCA1 are more resistant to AmB treatment, while cells lacking ABCA1 expression or expressing non-active ABCA1MM mutant display increased sensitivity. Further, a FLIM analysis of AmB-treated cells reveals a fraction of the antibiotic molecules, characterized by relatively high fluorescence lifetimes (> 6 ns), involved in formation of bulk cholesterol-AmB structures at the surface of ABCA1-expressing cells. Finally, lowering the cellular cholesterol content abolishes resistance of ABCA1-expressing cells to AmB. Therefore, we propose that ABCA1-mediated cholesterol efflux from cells induces formation of bulk cholesterol-AmB structures at the cell surface, preventing AmB cytotoxicity.

ABCA1 transporter reduces amphotericin B cytotoxicity in mammalian cells.

The plasma membrane (PM) spatiotemporal organization is one of the major factors controlling cell signaling and whole-cell homeostasis. The PM lipids, including cholesterol, determine the physicochemical properties of the membrane bilayer and thus play a crucial role in all membrane-dependent cellular processes. It is known that lipid content and distribution in the PM are not random, and their transversal and lateral organization is highly controlled. Mainly sphingolipid- and cholesterol-rich lipid nanodomains, historically referred to as rafts, are extremely dynamic "hot spots" of the PM controlling the function of many cell surface proteins and receptors. In the first part of this review, we will focus on the recent advances of PM investigation and the current PM concept. In the second part, we will discuss the importance of several classes of ABC transporters whose substrates are lipids for the PM organization and dynamics. Finally, we will briefly present the significance of lipid ABC transporters for immune responses.

ArticleTotal : 2	Year
Publication title Cited by 4	2012
Publication title Cited by 10	2020

Article	Year
Plant physiology\| PubMed ID: 16126865	2005
FEBS letters\| PubMed ID: 16506311	2006
Plant molecular biology\| PubMed ID: 18034327	2008
FASEB journal : official publication of the Federation of American Societies for Experimental Biology\| PubMed ID: 19151332	2009
Molecular plant pathology\| PubMed ID: 19694955	2009
Science signaling\| PubMed ID: 21467299	2011
Probing orientational behavior of MHC class I protein and lipid probes in cell membranes by fluorescence polarization-resolved imaging. Biophysical journal\| PubMed ID: 21767500	2011
Biochimica et biophysica acta\| PubMed ID: 21787882	2012
ABCA1 transporter reduces amphotericin B cytotoxicity in mammalian cells. Cellular and molecular life sciences : CMLS\| PubMed ID: 31134303	2019
Do ABC transporters regulate plasma membrane organization? Cellular & molecular biology letters\| PubMed ID: 32647530	2020

Tomasz Trombik

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