Insulin, Insulin-like Growth Factor-I, and Platelet-Derived Growth Factor Activate Extracellular Signal-Regulated Kinase by Distinct Pathways in Muscle Cells

2001 ◽  
Vol 288 (1) ◽  
pp. 205-211 ◽  
Author(s):  
Theodoros Tsakiridis ◽  
Evangelia Tsiani ◽  
Poli Lekas ◽  
Arik Bergman ◽  
Vera Cherepanov ◽  
...  
Keyword(s):  
Growth Factor ◽  
Muscle Cells ◽  
Platelet Derived Growth Factor ◽  
Insulin Like Growth Factor ◽  
Extracellular Signal Regulated Kinase ◽  
Factor I ◽  
Extracellular Signal ◽  
Growth Factor I

scholarly journals Phosphorylation of Nuclear Phospholipase C β1 by Extracellular Signal-Regulated Kinase Mediates the Mitogenic Action of Insulin-Like Growth Factor I

2001 ◽  
Vol 21 (9) ◽  
pp. 2981-2990 ◽  
Author(s):  
Aimin Xu ◽  
Pann-Ghill Suh ◽  
Nelly Marmy-Conus ◽  
Richard B. Pearson ◽  
Oh Yong Seok ◽  
...  
Keyword(s):  
Growth Factor ◽  
Phospholipase C ◽  
Critical Role ◽  
Insulin Like Growth Factor ◽  
Extracellular Signal Regulated Kinase ◽  
Factor I ◽  
Extracellular Signal ◽  
Mitogenic Action ◽  
Igf I ◽  
Growth Factor I

ABSTRACT It is well established that a phosphoinositide (PI) cycle which is operationally distinct from the classical plasma membrane PI cycle exists within the nucleus, where it is involved in both cell proliferation and differentiation. However, little is known about the regulation of the nuclear PI cycle. Here, we report that nucleus-localized phospholipase C (PLC) β1, the key enzyme for the initiation of this cycle, is a physiological target of extracellular signal-regulated kinase (ERK). Stimulation of Swiss 3T3 cells with insulin-like growth factor I (IGF-I) caused rapid nuclear translocation of activated ERK and concurrently induced phosphorylation of nuclear PLC β1, which was completely blocked by the MEK inhibitor PD 98059. Coimmunoprecipitation detected a specific association between the activated ERK and PLC β1 within the nucleus. In vitro studies revealed that recombinant PLC β1 could be efficiently phosphorylated by activated mitogen-activated protein kinase but not by PKA. The ERK phosphorylation site was mapped to serine 982, which lies within a PSSP motif located in the characteristic carboxy-terminal tail of PLC β1. In cells overexpressing a PLC β1 mutant in which serine 982 is replaced by glycine (S982G), IGF-I failed to activate the nuclear PI cycle, and its mitogenic effect was also markedly attenuated. Expression of S982G was found to inhibit ERK-mediated phosphorylation of endogenous PLC β1. This result suggests that ERK-evoked phosphorylation of PLC β1 at serine 982 plays a critical role in the activation of the nuclear PI cycle and is also crucial to the mitogenic action of IGF-I.

Growth advantage of human leiomyoma cells compared to normal smooth-muscle cells due to enhanced sensitivity toward insulin-like growth factor I

1994 ◽  
Vol 59 (3) ◽  
pp. 427-434 ◽  
Author(s):  
Leo T. M. Van Der Ven ◽  
Ton Gloudemans ◽  
Paul J. M. Roholl ◽  
Sylvia C. Van Buul-Offers ◽  
Bellinda A. Bladergroen ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Growth Factor ◽  
Smooth Muscle Cells ◽  
Muscle Cells ◽  
Insulin Like Growth Factor ◽  
Factor I ◽  
Enhanced Sensitivity ◽  
Growth Factor I
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