Premium
Insulin stimulates spreading of skeletal muscle cells involving the activation of focal adhesion kinase, phosphatidylinositol 3‐kinase and extracellular signal regulated kinases
Author(s) -
Goel Hira Lal,
Dey Chinmoy Sankar
Publication year - 2002
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.10161
Subject(s) - focal adhesion , paxillin , microbiology and biotechnology , insulin receptor , ptk2 , phosphatidylinositol , tyrosine kinase , kinase , map kinase kinase kinase , cyclin dependent kinase 9 , integrin linked kinase , biology , insulin , chemistry , mitogen activated protein kinase kinase , signal transduction , cyclin dependent kinase 2 , endocrinology , mapk/erk pathway , protein kinase a , insulin resistance
Insulin plays an important role in muscle cell survival and proliferation. However, there is no report showing the role of insulin in spreading of muscle cells. In the present report, we showed that insulin enhances muscle cell spreading concomitant with enhanced tyrosine phosphorylation of focal adhesion kinase (FAK) and paxillin. Moreover, insulin can stimulate the cell spreading even in presence of integrin α5 blockers although to a lesser extent as compared to control. Cell adhesion was not dependent on insulin and serum, and decreased in presence of integrin blockers. We found direct association of FAK with affinity purified insulin receptors using in vitro kinase assay. The increase in FAK tyrosine phosphorylation was associated with increase in its kinase activity and further supported by increased phosphotyrosine accumulation on focal adhesions and increased membrane localization of FAK after stimulation by insulin. Moreover, insulin‐mediated muscle cell spreading was dependent upon phosphatidylinositol 3‐kinase (PI 3‐kinase) activity. PI 3‐kinase activity was found to be associated with FAK and the FAK associated PI 3‐kinase activity enhanced when cells were plated in presence of insulin. We also observed activation of MAP kinases, i.e., ERK‐1/‐2 during insulin mediated muscle cell spreading. In conclusion, FAK, PI 3‐kinase, and MAP kinase are important components of pathway(s) that regulate insulin stimulated muscle cell spreading. © 2002 Wiley‐Liss, Inc.