Phosphatidylserine Asymmetry Promotes the Membrane Insertion of a Transmembrane Helix

摘要: Abstract The plasma membrane (PM) contains an asymmetric distribution of lipids between the inner and outer bilayer leaflets. A lipid special interest in eukaryotic membranes is negatively charged phosphatidylserine (PS). In healthy cells, PS actively sequestered to leaflet PM, but redistributes when cell damaged or at onset apoptosis. However, influence asymmetry on protein structure folding are poorly understood. pH low insertion peptide (pHLIP) adsorbs surface a neutral pH, it inserts into acidic pH. We have previously observed that symmetric vesicles, affects pHLIP by lowering midpoint insertion. Here, we studied effect interaction pHLIP. developed modified protocol create vesicles containing employed Annexin V labeled with Alexa Fluor 568 fluorophore as new probe quantify asymmetry. was promoted PS, which causes charge difference Our results indicate can modulate formation α-helix membrane. corollary model studies using bilayers mimic PM may fail capture important aspects protein-membrane interactions.