Morphological changes in liposomes caused by polymerization of encapsulated actin and spontaneous formation of actin bundles

Hidetake Miyata, Hirokazu Hotani

Research output: Contribution to journalArticlepeer-review

90 Citations (Scopus)

Abstract

Spherical giant liposomes that had encapsulated skeletal-muscle G-actin were made by swelling a dried lipid mixture of dimyristoyl phosphatidylcholine/cardiolipin, 1:1 (wt/wt), in a solution of G-actin/CaCl2 at 0°C. Polymerization of the encapsulated G-actin into actin filaments was achieved by raising the temperature to 30°C. We observed the subsequent shape changes of the liposomes by dark-field and differential interference-contrast light microscopy. After ≈40 min, which was required for completion of actin polymerization, two shapes of liposome were evident: dumbbell and disk. Elongation of the dumbbell-shaped liposomes was concomitant with actin polymerization. Polarization microscopy showed that actin filaments formed thick bundles in the liposomes and that these filaments lay contiguous to the periphery of the liposome. Localization of actin filaments in the liposomes was confirmed by observation of rhodamine phalloidin-conjugated actin filaments by fluorescence microscopy. Both dumbbell-and disk-shaped liposomes were rigid and kept their shapes as far as actin filaments were stabilized. In contrast, liposomes containing bovine serum albumin were fragile, and their shapes continually fluctuated from Brownian motion, indicating that the actin bundles served as mechanical support for the liposome shapes.

Original languageEnglish
Pages (from-to)11547-11551
Number of pages5
JournalProceedings of the National Academy of Sciences of the United States of America
Volume89
Issue number23
DOIs
Publication statusPublished - 1992 Dec 1
Externally publishedYes

Keywords

  • Cytoskeleton

ASJC Scopus subject areas

  • General

Fingerprint Dive into the research topics of 'Morphological changes in liposomes caused by polymerization of encapsulated actin and spontaneous formation of actin bundles'. Together they form a unique fingerprint.

Cite this