Abstract
Insulin-like growth factor-I (IGF-I) regulates muscle differentiation through phosphatidylinositol 3-kinase (PI 3-kinase). Also it was recently reported that PI 3-kinase is involved in the activation of phospholipase C-γ1 (PLC-γ1). We investigated whether PLC-γ1 therefore plays a role in IGF-I-induced muscle differentiation using H9c2 rat cardiac myoblasts as a model. IGF-I was able to activate PLC-γ1 via both PI 3-kinase-dependent and tyrosine phosphorylation-dependent mechanisms in this model. However, PI 3-kinase appeared to play a more important role than tyrosine phosphorylation in IGF-I activation of PLC-γ1. In addition, PLC-γ1 activation was independent of Akt/protein kinase B (Akt/PKB). Importantly, PLC-γ1 was involved in IGF-I-induced muscle differentiation in parallel with Akt/PKB. Taken together, these results suggest that IGF-I regulation of muscle differentiation is dependent on the activation of PLC-γ1 and Akt/PKB, both of which are downstream mediators of PI 3-kinase.
| Original language | English |
|---|---|
| Pages (from-to) | 816-822 |
| Number of pages | 7 |
| Journal | Biochemical and Biophysical Research Communications |
| Volume | 282 |
| Issue number | 3 |
| DOIs | |
| State | Published - 2001 |
Bibliographical note
Funding Information:We are very grateful to Dr. Julian Downward at the Imperial Cancer Research Fund Laboratory, United Kingdom, and Dr. Masato Kasuga at Kobe University, Japan, for providing us with vectors encoding a constitutively active (p110*) and a dominant negative (Δp85) form of PI3-kinase. Dr. Feng Hong is a recipient of fellowship provided by Korea United Pharmaceutical Inc.