Implication of phosphorylation of the myosin II regulatory light chain in insulin-stimulated GLUT4 translocation in 3T3-F442A adipocytes.
- Author:
Young Ok CHOI
1
;
Hee Jeong RYU
;
Hye Rim KIM
;
Young Sook SONG
;
Cheonghwan KIM
;
Wan LEE
;
Han CHOE
;
Chae Hun LEEM
;
Yeon Jin JANG
Author Information
1. Department of Physiology University of Ulsan College of Medicine, Seoul 138-736, Korea. yjjang@amc.seoul.kr
- Publication Type:Original Article ; Research Support, Non-U.S. Gov't
- Keywords:
calcium signaling;
glucose transporter type 4;
insulin;
myosin type II;
myosin-light-chain kinase;
phosphorylation
- MeSH:
Protein Transport/drug effects;
Phosphorylation;
Naphthalenes/pharmacology;
Myosin-Light-Chain Kinase/antagonists & inhibitors/*metabolism;
Myosin Type II/*metabolism;
Mice;
Insulin/*pharmacology;
Glucose Transporter Type 4/*metabolism;
Enzyme Inhibitors/pharmacology;
Dose-Response Relationship, Drug;
Calmodulin/antagonists & inhibitors/physiology;
Azepines/pharmacology;
Animals;
Adipocytes/cytology/*drug effects/metabolism;
3T3 Cells
- From:Experimental & Molecular Medicine
2006;38(2):180-189
- CountryRepublic of Korea
- Language:English
-
Abstract:
In adipocytes, insulin stimulates glucose transport primarily by promoting the translocation of GLUT4 to the plasma membrane. Requirements for Ca2+/ calmodulin during insulin-stimulated GLUT4 translocation have been demonstrated; however, the mechanism of action of Ca2+ in this process is unknown. Recently, myosin II, whose function in non-muscle cells is primarily regulated by phosphorylation of its regulatory light chain by the Ca2+/calmodulin-dependent myosin light chain kinase (MLCK), was implicated in insulin-stimulated GLUT4 translocation. The present studies in 3T3- F442A adipocytes demonstrate the novel finding that insulin significantly increases phosphorylation of the myosin II RLC in a Ca2+-dependent manner. In addition, ML-7, a selective inhibitor of MLCK, as well as inhibitors of myosin II, such as blebbistatin and 2,3-butanedione monoxime, block insulin- stimulated GLUT4 translocation and subsequent glucose transport. Our studies suggest that MLCK may be a regulatory target of Ca2+/calmodulin and may play an important role in insulin-stimulated glucose transport in adipocytes.
