Do unsaturated phosphoinositides mix with ordered phosphadidylcholine model membranes?

Phosphoinositides have been shown to control membrane trafficking events by targeting proteins to specific cellular sites, which requires a tight regulation of phosphoinositide generation and turnover as well as a high degree of compartmentalization. To shed light on the processes that lead to the f...

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Main Authors: Antje Hermelink, Gerald Brezesinski
Format: Article
Language:English
Published: Elsevier 2008-09-01
Series:Journal of Lipid Research
Subjects:
Online Access:http://www.sciencedirect.com/science/article/pii/S0022227520346605
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spelling doaj-cc81f44f5eca4b0ebb464a051ac985df2021-04-28T05:58:26ZengElsevierJournal of Lipid Research0022-22752008-09-0149919181925Do unsaturated phosphoinositides mix with ordered phosphadidylcholine model membranes?Antje Hermelink0Gerald Brezesinski1Max Planck Institute of Colloids and Interfaces, Research Campus Golm, 14476 Potsdam, GermanyMax Planck Institute of Colloids and Interfaces, Research Campus Golm, 14476 Potsdam, GermanyPhosphoinositides have been shown to control membrane trafficking events by targeting proteins to specific cellular sites, which requires a tight regulation of phosphoinositide generation and turnover as well as a high degree of compartmentalization. To shed light on the processes that lead to the formation of phosphoinositide-enriched microdomains, mixed monolayers of phosphatidylcholine and dioleoyl-phosphatidylinositol (DOPtdIns) or dioleoyl-phosphatidylinositol-bisphosphate [DOPtdIns(4,5)P2] were investigated by isothermal area/pressure measurements, Brewster angle microscopy, and grazing incidence X-ray diffraction. The results are consistent with a charge-dependent formation of phosphatidylinositol-containing tightly packed phases. DOPtdIns is capable of mixing partially with condensed 1,2-distearoyl-phosphatidylcholine (DSPC) and of forming mixed crystals that differ significantly from those formed by pure DSPC. DOPtdIns(4,5)P2 in mixtures with DSPC is, to a much larger extent, phase separated. The observed phase separation of the highly charged DOPtdIns(4,5)P2 is presumably water stabilized by electrostatic interactions and hydrogen bonding. In biological systems, an enzymatic phosphorylation of phosphatidylinositol in mixed domains may cause their insolubility in ordered phosphatidylcholine areas and lead to a cooperative reorganization of the host lipid membrane. This strong cooperative effect underlines the important role of PtdIns(4,5)P2 in signal transduction processes and suggests that the ability of phosphoinositides to induce or reduce long-range interactions in phospholipid mixtures is crucial.http://www.sciencedirect.com/science/article/pii/S0022227520346605DOPtdInsDOPtdIns(4,5)P21,2-distearoyl-phosphatidylcholinephase separationhydrogen bondingmonolayer structure
collection DOAJ
language English
format Article
sources DOAJ
author Antje Hermelink
Gerald Brezesinski
spellingShingle Antje Hermelink
Gerald Brezesinski
Do unsaturated phosphoinositides mix with ordered phosphadidylcholine model membranes?
Journal of Lipid Research
DOPtdIns
DOPtdIns(4,5)P2
1,2-distearoyl-phosphatidylcholine
phase separation
hydrogen bonding
monolayer structure
author_facet Antje Hermelink
Gerald Brezesinski
author_sort Antje Hermelink
title Do unsaturated phosphoinositides mix with ordered phosphadidylcholine model membranes?
title_short Do unsaturated phosphoinositides mix with ordered phosphadidylcholine model membranes?
title_full Do unsaturated phosphoinositides mix with ordered phosphadidylcholine model membranes?
title_fullStr Do unsaturated phosphoinositides mix with ordered phosphadidylcholine model membranes?
title_full_unstemmed Do unsaturated phosphoinositides mix with ordered phosphadidylcholine model membranes?
title_sort do unsaturated phosphoinositides mix with ordered phosphadidylcholine model membranes?
publisher Elsevier
series Journal of Lipid Research
issn 0022-2275
publishDate 2008-09-01
description Phosphoinositides have been shown to control membrane trafficking events by targeting proteins to specific cellular sites, which requires a tight regulation of phosphoinositide generation and turnover as well as a high degree of compartmentalization. To shed light on the processes that lead to the formation of phosphoinositide-enriched microdomains, mixed monolayers of phosphatidylcholine and dioleoyl-phosphatidylinositol (DOPtdIns) or dioleoyl-phosphatidylinositol-bisphosphate [DOPtdIns(4,5)P2] were investigated by isothermal area/pressure measurements, Brewster angle microscopy, and grazing incidence X-ray diffraction. The results are consistent with a charge-dependent formation of phosphatidylinositol-containing tightly packed phases. DOPtdIns is capable of mixing partially with condensed 1,2-distearoyl-phosphatidylcholine (DSPC) and of forming mixed crystals that differ significantly from those formed by pure DSPC. DOPtdIns(4,5)P2 in mixtures with DSPC is, to a much larger extent, phase separated. The observed phase separation of the highly charged DOPtdIns(4,5)P2 is presumably water stabilized by electrostatic interactions and hydrogen bonding. In biological systems, an enzymatic phosphorylation of phosphatidylinositol in mixed domains may cause their insolubility in ordered phosphatidylcholine areas and lead to a cooperative reorganization of the host lipid membrane. This strong cooperative effect underlines the important role of PtdIns(4,5)P2 in signal transduction processes and suggests that the ability of phosphoinositides to induce or reduce long-range interactions in phospholipid mixtures is crucial.
topic DOPtdIns
DOPtdIns(4,5)P2
1,2-distearoyl-phosphatidylcholine
phase separation
hydrogen bonding
monolayer structure
url http://www.sciencedirect.com/science/article/pii/S0022227520346605
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