Activation of dynamin II by POPC in giant unilamellar vesicles: a two-photon fluorescence microscopy study.
The interaction of dynamin II with giant unilamellar vesicles was studied using two-photon fluorescence microscopy. Dynamin II, labeled with fluorescein, was injected into a microscope chamber containing giant unilamellar vesicles, which were composed of either pure 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) or a mixture of POPC and phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). Binding of the fluorescent dynamin II to giant unilamellar vesicles, in the presence and absence of PI(4,5)P2, was directly observed using two-photon fluorescence microscopy. This binding was also visualized using the fluorescent N-methylanthraniloyl guanosine 5'-[gamma-thio]triphosphate analogue. The membrane probe 6-dodecanoyl-2-dimethylamine-naphthalene was used to monitor the physical state of the lipid in the giant unilamellar vesicles in the absence and presence of dynamin. A surprising finding was the fact that dynamin II bound to vesicles in the absence of PI(4,5)P2. Activation of the GTPase activity of dynamin II by pure POPC was then shown.
Bagatolli
L A
LA
Grupo de Biofisica, Dpto. de Química Biológica, Fac. de Ciencias Químicas, UNC, Pabellón Argentina, Ciudad Universitaria, 5000, Córdoba, Argentina.
Binns
D D
DD
Jameson
D M
DM
Albanesi
J P
JP
D034285:Dynamin II / Q000737:chemistry / Q000378:metabolism*; D008856:Microscopy, Fluorescence / Q000379:methods*; D010712:Phosphatidic Acids / Q000737:chemistry*; D017785:Photons
C103238:1-palmitoyl-2-oleoyl-glycero-3-phosphatidic acid; D010712:Phosphatidic Acids; D034285:Dynamin II