Difference in lipid packing sensitivity of exchangeable apolipoproteins apoA-I and apoA-II: An important determinant for their distinctive role in lipid metabolism. - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Biochimica et Biophysica Acta:Biomembranes Année : 2012

Difference in lipid packing sensitivity of exchangeable apolipoproteins apoA-I and apoA-II: An important determinant for their distinctive role in lipid metabolism.

Gérard Le Caër
Anne Renault
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Véronique Vié
Sylvie Beaufils

Résumé

Exchangeable apolipoproteins A-I and A-II play distinct roles in reverse cholesterol transport. ApoA-I interacts with phospholipids and cholesterol of the cell membrane to make high density lipoprotein particles whereas apolipoprotein A-II interacts with high density lipoprotein particles to release apolipoprotein A-I. The two proteins show a high activity at the aqueous solution/lipid interface and are characterized by a high content of amphipathic α-helices built upon repetition of the same structural motif. We set out to investigate to what extent the number of α-helix repeats of this structural motif modulates the affinity of the protein for lipids and the sensitivity to lipid packing. To this aim we have compared the insertion of apolipoproteins A-I and A-II in phospholipid monolayers formed on a Langmuir trough in conditions where lipid packing, surface pressure and charge were controlled. We also used atomic force microscopy to obtain high resolution topographic images of the surface at a resolution of several nanometers and performed statistical image analysis to calculate the spatial distribution and geometrical shape of apolipoproteins A-I and A-II clusters. Our data indicate that apolipoprotein A-I is sensitive to packing of zwitterionic lipids but insensitive to the packing of negatively charged lipids. Interestingly, apolipoprotein A-II proved to be insensitive to the packing of zwitterionic lipids. The different sensitivity to lipid packing provides clues as to why apolipoprotein A-II barely forms nascent high density lipoprotein particles while apolipoprotein A-I promotes their formation. We conclude that the different interfacial behaviors of apolipoprotein A-I and apolipoprotein A-II in lipidic monolayers are important determinants of their distinctive roles in lipid metabolism.

Dates et versions

hal-00732810 , version 1 (17-09-2012)

Identifiants

Citer

Lionel Chièze, Victor Martin Bolanos-Garcia, Gérard Le Caër, Anne Renault, Véronique Vié, et al.. Difference in lipid packing sensitivity of exchangeable apolipoproteins apoA-I and apoA-II: An important determinant for their distinctive role in lipid metabolism.. Biochimica et Biophysica Acta:Biomembranes, 2012, 1818 (11), pp.2732-41. ⟨10.1016/j.bbamem.2012.05.016⟩. ⟨hal-00732810⟩
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