title: Trace membrane additives affect lipid phases with distinct mechanisms: a modified Ising model.
abstract: The addition of trace molecules into membranes can significantly alter the morphology of the co-existing liquid phases and lipid phase transition temperature. Membrane additives may affect lipid phase dynamics through preferentially partitioning to the boundary between lipid phases or preferentially mixing into one lipid phase. The characteristic differences between these mechanisms are demonstrated here in a minimalistic nearest neighbor model to provide a framework for how slight changes to membrane composition may affect lipid-phase-dependent processes, such as lipid-raft formation, immunological signaling, and molecular sorting preceding endocytosis with coexisting liquid phases. Within the low mole fractions explored here (≤3 mol%), increasing the additive concentration linearly changed the phase miscibility temperature. Rotationally asymmetric Janus particles reduced the miscibility transition temperature for all fractions and degree of phase polarization. Rotationally symmetric additives, however, either increased or decreased the phase miscibility temperature depending on the phase preference of the additive. While most experimental molecules may contain aspects of both of these idealized additives, this model provides a broad framework to quantify the effects of membrane additives in regard to lipid phase preference, lipid-raft association, and contribution to lipid phase-dependent molecular sorting.
authors.affiliation: Department of Physics and Astronomy, Wayne State University, Detroit, MI, USA.
authors.forename: Rebecca L
authors.initials: RL
authors.lastname: Meerschaert
authors.forename: Christopher V
authors.initials: CV
authors.lastname: Kelly
mesh_terms: D008051:Lipid Bilayers / Q000737:chemistry*; D008055:Lipids / Q000737:chemistry*; D008956:Models, Chemical; D044367:Phase Transition; D044366:Transition Temperature
chemical_list: D008051:Lipid Bilayers; D008055:Lipids
references.citation: Phys Rev Lett. 2008 Jan 25;100(3):037802
references.pmid: 18233038
references.citation: Biophys J. 2013 Dec 17;105(12):2751-9
references.pmid: 24359747
references.citation: Biophys J. 2008 Jul;95(1):236-46
references.pmid: 18424504
references.citation: Langmuir. 2014 Feb 11;30(5):1361-9
references.pmid: 24456489
references.citation: Biophys J. 2009 Aug 19;97(4):1087-94
references.pmid: 19686656
references.citation: Biophys J. 2010 Nov 17;99(10):3309-18
references.pmid: 21081079
references.citation: Biophys J. 2011 Apr 6;100(7):1668-77
references.pmid: 21463580
references.citation: Proc Natl Acad Sci U S A. 2007 Nov 6;104(45):17650-5
references.pmid: 17962417
references.citation: PLoS One. 2012;7(2):e31457
references.pmid: 22384026
references.citation: Proc Natl Acad Sci U S A. 2008 Jul 22;105(29):10005-10
references.pmid: 18621689
references.citation: J Am Chem Soc. 2006 Jan 11;128(1):192-201
references.pmid: 16390147
references.citation: Langmuir. 2014 Oct 7;30(39):11734-45
references.pmid: 25184568
references.citation: ACS Chem Biol. 2008 May 16;3(5):287-93
references.pmid: 18484709
references.citation: J Phys Chem B. 2007 Jan 25;111(3):502-4
references.pmid: 17228905
references.citation: Chem Phys Lipids. 2014 Feb;178:77-83
references.pmid: 24361549
references.citation: Proc Natl Acad Sci U S A. 2012 May 22;109(21):8097-102
references.pmid: 22562795
references.citation: FASEB J. 2010 Oct;24(10):3662-73
references.pmid: 20484671
references.citation: J Phys Chem B. 2014 Jul 31;118(30):9028-36
references.pmid: 25003709
references.citation: Phys Rev Lett. 2012 Sep 28;109(13):138101
references.pmid: 23030121
references.citation: Proc Natl Acad Sci U S A. 2001 Sep 11;98(19):10642-7
references.pmid: 11535814
references.citation: J Biol Chem. 2010 Nov 5;285(45):35188-95
references.pmid: 20826816
references.citation: Biochim Biophys Acta. 2007 Nov;1768(11):2777-86
references.pmid: 17931595
references.citation: Biophys J. 2007 Nov 1;93(9):3113-9
references.pmid: 17660324
references.citation: Phys Rev E Stat Nonlin Soft Matter Phys. 2013 Sep;88(3):032708
references.pmid: 24125295
references.citation: Langmuir. 2013 Apr 30;29(17):5246-61
references.pmid: 23530895
references.citation: Biochim Biophys Acta. 2007 Nov;1768(11):2764-76
references.pmid: 17825247
references.citation: Biochim Biophys Acta. 1991 Aug 26;1067(2):241-53
references.pmid: 1878375
references.citation: Biophys J. 2006 Sep 15;91(6):2184-97
references.pmid: 16798807
references.citation: Biochem J. 2009 Dec 1;424(2):163-7
references.pmid: 19811449
references.citation: Phys Rev Lett. 2012 Jun 29;108(26):265702
references.pmid: 23004996
references.citation: Biophys J. 2007 Apr 1;92(7):2422-33
references.pmid: 17218467
references.citation: J Am Chem Soc. 2012 Oct 17;134(41):17278-85
references.pmid: 22994893