scholarly journals Late Endosomal Traffic of the Epidermal Growth Factor Receptor Ensures Spatial and Temporal Fidelity of Mitogen-activated Protein Kinase Signaling

2007 ◽  
Vol 18 (12) ◽  
pp. 4698-4710 ◽  
Author(s):  
N. Taub ◽  
D. Teis ◽  
H. L. Ebner ◽  
M. W. Hess ◽  
L. A. Huber

Mitogen-activated protein kinase (MAPK) signaling is regulated by assembling distinct scaffold complexes at the plasma membrane and on endosomes. Thus, spatial resolution might be critical to determine signaling specificity. Therefore, we investigated whether epidermal growth factor receptor (EGFR) traffic through the endosomal system provides spatial information for MAPK signaling. To mislocalize late endosomes to the cell periphery we used the dynein subunit p50 dynamitin. The peripheral translocation of late endosomes resulted in a prolonged EGFR activation on late endosomes and a slow down in EGFR degradation. Continuous EGFR signaling from late endosomes caused sustained extracellular signal-regulated kinase and p38 signaling and resulted in hyperactivation of nuclear targets, such as Elk-1. In contrast, clustering late endosomes in the perinuclear region by expression of dominant active Rab7 delayed the entry of the EGFR into late endosomes, which caused a delay in EGFR degradation and a sustained MAPK signaling. Surprisingly, the activation of nuclear targets was reduced. Thus, we conclude that appropriate trafficking of the activated EGFR through endosomes controls the spatial and temporal regulation of MAPK signaling.

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.


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