title: Absence of clustering of phosphatidylinositol-(4,5)-bisphosphate in fluid phosphatidylcholine.
abstract: Phosphatidylinositol-(4,5)-bisphosphate [PI(4,5)P(2)] plays a key role in the modulation of actin polymerization and vesicle trafficking. These processes seem to depend on the enrichment of PI(4,5)P(2) in plasma membrane domains. Here, we show that PI(4,5)P(2) does not form domains when in a fluid phosphatidylcholine matrix in the pH range of 4.8-8.4. This finding is at variance with the spontaneous segregation of PI(4,5)P(2) to domains as a mechanism for the compartmentalization of PI(4,5)P(2) in the plasma membrane. Water/bilayer partition of PI(4,5)P(2) is also shown to be dependent on the protonation state of the lipid.
authors.affiliation: Centro de Química-Física Molecular, Instituto Superior Técnico, Lisbon, Portugal. fernandesf@ist.utl.pt
authors.forename: Fábio
authors.initials: F
authors.lastname: Fernandes
authors.forename: Luís M S
authors.initials: LM
authors.lastname: Loura
authors.forename: Alexander
authors.initials: A
authors.lastname: Fedorov
authors.forename: Manuel
authors.initials: M
authors.lastname: Prieto
mesh_terms: D002451:Cell Compartmentation; D031541:Fluorescence Resonance Energy Transfer; D006863:Hydrogen-Ion Concentration; D066298:In Vitro Techniques; D008051:Lipid Bilayers / Q000737:chemistry; D008563:Membrane Lipids / Q000737:chemistry; D021962:Membrane Microdomains / Q000737:chemistry; D008954:Models, Biological; D010713:Phosphatidylcholines / Q000737:chemistry*; D019269:Phosphatidylinositol 4,5-Diphosphate / Q000737:chemistry*
chemical_list: D008051:Lipid Bilayers; D008563:Membrane Lipids; D010713:Phosphatidylcholines; D019269:Phosphatidylinositol 4,5-Diphosphate; C028694:1-palmitoyl-2-oleoylphosphatidylcholine