The Platelet-Activating Factor Receptor Activates the Extracellular Signal-Regulated Kinase Mitogen-Activated Protein Kinase and Induces Proliferation of Epidermal Cells through an Epidermal Growth Factor-Receptor-Dependent Pathway

2002 ◽  
Vol 300 (3) ◽  
pp. 1026-1035 ◽  
Author(s):  
Silvio A. Marques ◽  
Lady C. Dy ◽  
Michael D. Southall ◽  
Quiaofang Yi ◽  
Eva Smietana ◽  
...  
1994 ◽  
Vol 14 (11) ◽  
pp. 7527-7534
Author(s):  
E R Eldredge ◽  
G M Korf ◽  
T A Christensen ◽  
D C Connolly ◽  
M J Getz ◽  
...  

The intrinsic tyrosine kinase activity of the epidermal growth factor receptor (EGFR) has been shown to be responsible for many of the pleiotropic intracellular effects resulting from ligand stimulation [W.S. Chen, C.S. Lazar, M. Poenie, R.Y. Tsien, G.N. Gill, and M.G. Rosenfeld, Nature (London) 328:820-823, 1987; A.M. Honegger, D. Szapary, A. Schmidt, R. Lyall, E. Van Obberghen, T.J. Dull, A. Ulrich, and J. Schlessinger, Mol. Cell. Biol. 7:4568-4571, 1987]. Recently, however, it has been shown that addition of ligand to cells expressing kinase-defective EGFR mutants can result in the phosphorylation of mitogen-activated protein kinase (R. Campos-González and J.R. Glenney, Jr., J. Biol. Chem. 267:14535-14538, 1992; E. Selva, D.L. Raden, and R.J. Davis, J. Biol. Chem. 268:2250-2254, 1993), as well as stimulation of DNA synthesis (K.J. Coker, J.V. Staros, and C.A. Guyer, Proc. Natl. Acad. Sci. USA 91:6967-6971, 1994). Moreover, mitogen-activated protein kinase has been shown to phosphorylate the transcription factor p62TCF in vitro, leading to enhanced ternary complex formation between p62TCF, p67SRF, and the c-fos serum response element (SRE) [H. Gille, A.D. Sharrocks, and P.E. Shaw, Nature (London) 358:414-417, 1992]. On the basis of these observations, we have investigated the possibility that the intrinsic tyrosine kinase activity of the EGFR may not be necessary for transcriptional activation mediated via p62TCF. Here, we demonstrate that a kinase-defective EGFR mutant can signal ligand-induced expression of c-fos protein and that a significant component of this induction appears to be mediated at the transcriptional level. Investigation of transcriptional activation mediated by the c-fos SRE shows that this response is impaired by mutations in the SRE which eliminate binding of p62(TCF). These data indicate that information inherent in the structure of the EGFR can be accessed by ligand stimulation independent of the receptor's catalytic kinase function.


2000 ◽  
Vol 350 (3) ◽  
pp. 655-661 ◽  
Author(s):  
Peter J. MANNON ◽  
Jennifer M. MELE

The G-protein-coupled peptide YY (PYY)/neuropeptide Y Y1 receptor (Y1R) subtype is highly expressed in the proliferative zone of human colonic crypt epithelial cells but biochemical and biological support for growth effects have been lacking. Using a model gut epithelial cell system, we have stably expressed the human Y1R in IEC-6 cells and show that the Y1R does couple to mitogen-activated protein kinase (MAPK) phosphorylation and cell growth. This pathway uses pertussis-toxin-sensitive G-proteins and βγ subunits, inhibited by co-transfected α-transducin. The Src-family tyrosine kinase inhibitor PP1, as well as specific inhibition of the epidermal growth factor receptor tyrosine kinase (EGFR TK) by PD153035, also blocks PYY stimulation of MAPK. This pathway further requires protein kinase C with EGFR TK inhibition blocking PYY-induced protein kinase Cε (PKCε) translocation to the cell membrane. Finally, we show that PYY stimulates growth in Y1R-expressing gut epithelial cells that is dependent on EGFR TK activity. These results demonstrate a novel pathway involving Gi/Go protein, EGFR and PKC to activate MAPK. Further, they support a role for PYY and the Y1R in regulating growth in human colonic epithelium.


Sign in / Sign up

Export Citation Format

Share Document