Optical Control of Lipid Rafts with Photoswitchable Ceramides.
Ceramide is a pro-apoptotic sphingolipid with unique physical characteristics. Often viewed as a second messenger, its generation can modulate the structure of lipid rafts. We prepared three photoswitchable ceramides, ACes, which contain an azobenzene photoswitch allowing for optical control over the N-acyl chain. Using combined atomic force and confocal fluorescence microscopy, we demonstrate that the ACes enable reversible switching of lipid domains in raft-mimicking supported lipid bilayers (SLBs). In the trans-configuration, the ACes localize into the liquid-ordered (Lo) phase. Photoisomerization to the cis-form triggers a fluidification of the Lodomains, as liquid-disordered (Ld) "lakes" are formed within the rafts. Photoisomerization back to the trans-state with blue light stimulates a rigidification inside the Ldphase, as the formation of small Lodomains. These changes can be repeated over multiple cycles, enabling a dynamic spatiotemporal control of the lipid raft structure with light.
Department of Chemistry and Center for Integrated Protein Science, Ludwig Maximilians University Munich , Butenandtstraße 5-13, 81377 Munich, Germany.
James Allen
JA
Frank
Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry , Am Klopferspitz 18, 82152 Martinsried, Germany.
Henri G
HG
Franquelim
Department of Cellular and Molecular Biophysics, Max Planck Institute of Biochemistry , Am Klopferspitz 18, 82152 Martinsried, Germany.
Petra
P
Schwille
Department of Chemistry and Center for Integrated Protein Science, Ludwig Maximilians University Munich , Butenandtstraße 5-13, 81377 Munich, Germany.
Dirk
D
Trauner
D002518:Ceramides / Q000737:chemistry / Q000378:metabolism*; D007536:Isomerism; D008027:Light; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D021962:Membrane Microdomains / Q000528:radiation effects*; D055620:Optical Phenomena
D002518:Ceramides; D008051:Lipid Bilayers