title: Myosin in hepatocytes is essential for bile canalicular contraction.
abstract: Active dynamic contraction of bile canaliculi has been observed in cultured doublet hepatocytes using time-lapse cinephotomicrography. This contractile movement plays an important role in normal bile formation. The mechanism of bile canalicular contraction has been proved to involve the Ca(2+)-calmodulin system and pericanalicular actin filaments. However, the role of myosin in this system is still unknown. In this study, using the newly synthesized myosin light-chain kinase inhibitor ML-9, we found that the treatment of cultured doublet hepatocytes with ML-9 inhibited canalicular contraction. This inhibitory effect suggests that myosin is involved in this complex cellular function and that the integrity of the actin-myosin system, as well as the Ca(2+)-calmodulin system is essential for normal bile canalicular contraction.
authors.affiliation: Department of Gastroenterology, Juntendo University School of Medicine, Tokyo, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Watanabe
authors.forename: A
authors.initials: A
authors.lastname: Miyazaki
authors.forename: M
authors.initials: M
authors.lastname: Hirose
authors.forename: M
authors.initials: M
authors.lastname: Takeuchi
authors.forename: H
authors.initials: H
authors.lastname: Ohide
authors.forename: T
authors.initials: T
authors.lastname: Kitamura
authors.forename: T
authors.initials: T
authors.lastname: Ueno
authors.forename: E
authors.initials: E
authors.lastname: Kominami
authors.forename: N
authors.initials: N
authors.lastname: Sato
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001381:Azepines; D001648:Bile Canaliculi / Q000502:physiology*; D002478:Cells, Cultured; D008099:Liver / Q000166:cytology / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D009219:Myosin-Light-Chain Kinase / Q000037:antagonists & inhibitors; D009218:Myosins / Q000378:metabolism / Q000502:physiology*; D013194:Staining and Labeling; D014743:Videotape Recording
chemical_list: D000199:Actins; D001381:Azepines; C056218:ML 9; D009219:Myosin-Light-Chain Kinase; D009218:Myosins