TY - JOUR
T1 - Liposomal internal viscosity affects the fate of membrane deformation induced by hypertonic treatment
AU - Fujiwara, Kei
AU - Yanagisawa, Miho
N1 - Funding Information:
We thank Prof. Shigeyuki Komura and Prof. Ryuichi Okamoto (Tokyo Metropolitan University), and Prof. Ken-ichi Yoshikawa (Doshisha University) for helpful discussions, and Mr Keisuke Kanagawa for assistance of FCS data collection. We also thank our daughter, Honoka Fujiwara, for sleeping during our paper writing. This work was supported by JSPS KAKENHI Grant Number JP15KT0081, JP15H00826 for K. F., and JP15H05463, JP16H00796 for M. F.
PY - 2017
Y1 - 2017
N2 - Artificial lipid membranes have been utilized to understand the physical mechanisms of the deformation patterns of live cells. However, typical artificial membrane systems contain only dilute components compared to those in the cytoplasm of live cells. By using giant unilamellar liposomes containing dense protein solutions similar to those in live cells, we here reveal that viscosity derived from internal crowding affects the deformation patterns of lipid membranes. After hypertonic treatment, liposome deformation patterns transitioned from budding to tubing when the initial internal macromolecular concentrations were increased. Remarkably, instead of observing different transition concentrations between two species of macromolecules, the viscosity at the transition concentration was found to be similar. Further analyses clearly demonstrated that the internal viscosity affects the deformation patterns of lipid membranes induced by hypertonic treatment. These results indicate that the viscosity of the cytoplasm is a key factor in determining cell deformation, and suggest the association of a process involving dynamic instability, such as a viscous fingering phenomenon, during the determination of deformation patterns by hypertonic treatment.
AB - Artificial lipid membranes have been utilized to understand the physical mechanisms of the deformation patterns of live cells. However, typical artificial membrane systems contain only dilute components compared to those in the cytoplasm of live cells. By using giant unilamellar liposomes containing dense protein solutions similar to those in live cells, we here reveal that viscosity derived from internal crowding affects the deformation patterns of lipid membranes. After hypertonic treatment, liposome deformation patterns transitioned from budding to tubing when the initial internal macromolecular concentrations were increased. Remarkably, instead of observing different transition concentrations between two species of macromolecules, the viscosity at the transition concentration was found to be similar. Further analyses clearly demonstrated that the internal viscosity affects the deformation patterns of lipid membranes induced by hypertonic treatment. These results indicate that the viscosity of the cytoplasm is a key factor in determining cell deformation, and suggest the association of a process involving dynamic instability, such as a viscous fingering phenomenon, during the determination of deformation patterns by hypertonic treatment.
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U2 - 10.1039/c7sm01421j
DO - 10.1039/c7sm01421j
M3 - Article
C2 - 29184957
AN - SCOPUS:85038363952
VL - 13
SP - 9192
EP - 9198
JO - Soft Matter
JF - Soft Matter
SN - 1744-683X
IS - 48
ER -