1: Biophys J  1994 Aug;67(2):922-8 

Transformation of actin-encapsulating liposomes induced by cytochalasin D.

Miyata H, Kinosita K Jr.

Department of Physics, Faculty of Science and Technology, Keio University,
Yokohama, Japan.

Liposomes encapsulating actin filaments were prepared by swelling at 0 degrees C
lipid film consisting of a mixture of dimyristoyl phosphatidylcholine and
cardiolipin (equal amounts by weight) in 100 microM rabbit skeletal muscle actin
and 0.5 mM CaCl2 followed by polymerization of actin at 30 degrees C. Liposomes
initially assumed either disk or dumbbell shape, but when cytochalasin D was
added to the medium surrounding the liposomes, they were found to become spindle
shaped. Liposomes containing bovine serum albumin that were given cytochalasin D
and actin-containing liposomes that were given dimethylformamide, the solvent
for cytochalasin D, did not transform. These results indicated
actin-cytochalasin interaction is involved in the transformation process.
Falling-ball viscometry and sedimentation analysis of actin solution indicated
that cytochalasin cleaved actin filaments and caused depolymerization. The
observation of polarized fluorescence of encapsulated actin labeled with
acrylodan indicated that the actin filaments in the transformed liposomes
aligned along the long axis of the liposomes. Because the actin filaments in the
disk- or dumbbell-shaped liposomes formed bundles running along the liposome
contour, the transformation was likely to be accompanied by the change in the
actin filament arrangement in the liposomes, which was induced by
actin-cytochalasin interaction.

PMID: 7948706 [PubMed - indexed for MEDLINE]