Linactants: Surfactant Analogues in Two Dimensions

Trabelsi, Siwar; Zhang, Shishan; Lee, T. Randall; Schwartz, Daniel K.

doi:10.1103/physrevlett.100.037802

Cited by 74 publications

(83 citation statements)

References 11 publications

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“…The peptide preferentially adsorbs at the Lo∕Ld domain interface (see SI Appendix). This result confirms that hydrophobic mismatch also plays an important role for the sorting of integral membrane proteins, and we predict that proteins that do not fit well into the Ld domain may display "linactant" (57,58) behavior at the Lo∕Ld interface. Also TM peptides with several palmitoyl anchors can accumulate at the domain interface (see SI Appendix).…”

Section: Discussionsupporting

confidence: 80%

Lipid packing drives the segregation of transmembrane helices into disordered lipid domains in model membranes

Schäfer

Jong

Holt

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

227

265

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Cell membranes are comprised of multicomponent lipid and protein mixtures that exhibit a complex partitioning behavior. Regions of structural and compositional heterogeneity play a major role in the sorting and self-assembly of proteins, and their clustering into higher-order oligomers. Here, we use computer simulations and optical microscopy to study the sorting of transmembrane helices into the liquid-disordered domains of phase-separated model membranes, irrespective of peptide-lipid hydrophobic mismatch. Free energy calculations show that the enthalpic contribution due to the packing of the lipids drives the lateral sorting of the helices. Hydrophobic mismatch regulates the clustering into either small dynamic or large static aggregates. These results reveal important molecular driving forces for the lateral organization and self-assembly of transmembrane helices in heterogeneous model membranes, with implications for the formation of functional protein complexes in real cells.fluorescence microscopy | lipid rafts | membrane proteins | molecular dynamics | linactants T he heterogeneity of biological membranes plays an important role in cellular function (1, 2). Despite experimental progress in recent years (3), the characterization of lateral organization in biological membranes, however, remains challenging due to the lack of tools to study fluctuating nanoscale assemblies in living cells (4-6). Model membranes (7-10) as well as isolated plasma membranes (11, 12) are more frequently studied, because largescale phase separation can be observed in these systems. In particular, at cholesterol concentrations reminiscent of biological membranes (10-30 mol % cholesterol), ternary mixtures of saturated and unsaturated lipids can segregate into coexisting lipid domains of different fluidity, a liquid-ordered (Lo) and a liquiddisordered (Ld) phase. Probing the structural and dynamical properties of these fluid domains has received a lot of attention, as it is presumably linked to the formation of lipid nanodomains ("rafts") in real cells (13,14).The structure and function of membrane proteins is intimately connected with their lipid environment (15, 16). Because of the heterogeneity of the cell membrane, proteins partition between different lipid domains, are recruited to specific locations, and form functional complexes (17)(18)(19). This lateral organization is very important for various cellular processes, such as membrane fusion (20, 21), protein trafficking (22), and signal transduction (23-25). Although lipids and integral membrane proteins are well studied by themselves, the molecular properties that determine the specific interactions between them remain poorly understood. Interactions important for protein sorting and self-assembly are (specific) protein-protein and protein-lipid forces, and indirect lipid-mediated forces. The latter category includes, for instance, forces due to entropic confinement of lipid chains and forces arising from the mismatch between the hydrophobic parts of the protein and the bi...

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Section: Discussionsupporting

confidence: 80%

Lipid packing drives the segregation of transmembrane helices into disordered lipid domains in model membranes

Schäfer

Jong

Holt

et al. 2011

Proc. Natl. Acad. Sci. U.S.A.

227

265

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“…H-Ras and N-Ras) bear both raft-preferring (palmitate) and raft-avoiding (prenyl) lipidations. It has been proposed that this combination may confer affinity to the interface between raft and non-raft domains (Weise, Triola et al 2009), with a potential role for these proteins as line-active modifiers of domain separation (Trabelsi, Zhang et al 2008).…”

Section: Y R I S T O Y L a T I O Nmentioning

confidence: 99%

Structural determinants of protein partitioning into ordered membrane domains and lipid rafts

Lorent

Levental

2015

Chemistry and Physics of Lipids

146

151

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“…Once these peptides have been inserted in membranes, which requires their central region to be hydrophobic enough, their amphipathic imbalance makes them two-dimensional equivalents of surfactants, for which the appropriate name linactant has recently been proposed. [95,96] In a process that is closely analogous to the formation of inverted micelles, these linactants can then aggregate to form pores, in which all their hydrophilic strips point toward the opening of the pore. [97] This event relies on a cooperative action of several peptides, thus providing (at least) a partial explanation for the experimentally observed strong sigmoidal (essentially threshold-like) dependence of antimicrobial activity as a function of peptide-lipid ratio.…”

Section: Pore-formation By Amphipathic Peptidesmentioning

confidence: 99%

Mesoscopic Membrane Physics: Concepts, Simulations, and Selected Applications

Deserno

2009

Macromol. Rapid Commun.

117

104

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The window of a few tens to a few hundred nanometers in length scale is a booming field in lipid membrane research, owing largely to two reasons. First, many exciting biophysical and cell biological processes take place within it. Second, experimental techniques manage to zoom in on this sub-optical scale, while computer simulations zoom out to system sizes previously unattainable, and both will be meeting soon. This paper reviews a selection of questions and concepts in this field and demonstrates that they can often be favorably addressed with highly simplified simulation models. Among the topics discussed are membrane adhesion to substrates, mixed lipid bilayers, lipid curvature coupling, pore formation by antimicrobial peptides, composition-driven protein aggregation, and curvature driven vesiculation.

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Linactants: Surfactant Analogues in Two Dimensions

Cited by 74 publications

References 11 publications

Lipid packing drives the segregation of transmembrane helices into disordered lipid domains in model membranes

Lipid packing drives the segregation of transmembrane helices into disordered lipid domains in model membranes

Structural determinants of protein partitioning into ordered membrane domains and lipid rafts

Mesoscopic Membrane Physics: Concepts, Simulations, and Selected Applications

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