Reconstruction of active regular motion in amoeba extract: dynamic cooperation between sol and gel states.
Amoeboid locomotion is one of the typical modes of biological cell migration. Cytoplasmic sol-gel conversion of an actomyosin system is thought to play an important role in locomotion. However, the mechanisms underlying sol-gel conversion, including trigger, signal, and regulating factors, remain unclear. We developed a novel model system in which an actomyosin fraction moves like an amoeba in a cytoplasmic extract. Rheological study of this model system revealed that the actomyosin fraction exhibits shear banding: the sol-gel state of actomyosin can be regulated by shear rate or mechanical force. Furthermore, study of the living cell indicated that the shear-banding property also causes sol-gel conversion with the same order of magnitude as that of shear rate. Our results suggest that the inherent sol-gel transition property plays an essential role in the self-regulation of autonomous translational motion in amoeba.
Department of Life Science, Graduate School of Life Science, University of Hyogo, Harima Science Park City, Hyogo, Japan.
Yukinori
Y
Nishigami
Masatoshi
M
Ichikawa
Toshiya
T
Kazama
Ryo
R
Kobayashi
Teruo
T
Shimmen
Kenichi
K
Yoshikawa
Seiji
S
Sonobe
D000656:Amoeba / Q000502:physiology* / Q000648:ultrastructure; D008124:Locomotion / Q000502:physiology; D046529:Microscopy, Electron, Transmission