Synergistic induction of mitogen-activated protein kinase phosphatase-1 by thrombin and epidermal growth factor requires vascular endothelial growth factor receptor-2.
OBJECTIVE
To determine the molecular mechanism underlying the synergistic response of mitogen-activated protein kinase phosphatase-1 (MKP-1), which is induced by thrombin and epidermal growth factor (EGF).


RESULTS
MKP-1 induction by thrombin (approximately 6-fold) was synergistically increased (approximately 18-fold) by cotreatment with EGF in cultured endothelial cells. EGF alone did not induce MKP-1 substantially (<2-fold). The synergistic induction of MKP-1 was not mediated by matrix metalloproteinases. The EGF receptor kinase inhibitor AG1478 blocked approximately 70% of MKP-1 induction by thrombin plus EGF (from 18- to 6-fold) but not the response to thrombin alone. An extracellular signal-regulated kinase (ERK)-dependent protease-activated receptor-1 (PAR-1) signal was required for the thrombin alone effect; an ERK-independent PAR-1 signal was necessary for the approximately 12-fold MKP-1 induction by thrombin plus EGF. VEGF induction of MKP-1 was also approximately 12-fold and c-Jun N-terminal kinase (JNK) dependent. Inhibitors of extracellular signal-regulated kinase and JNK activation blocked thrombin plus EGF-induced MKP-1 completely. Furthermore, VEGF receptor 2 depletion blocked the synergistic response without affecting the induction of MKP-1 by thrombin alone.


CONCLUSIONS
We have identified a novel signaling interaction between protease-activated receptor-1 and EGF receptor that is mediated by VEGF receptor 2 and results in synergistic MKP-1 induction.
Chandrasekharan
Unni M
UM
Department of Cell Biology, Cleveland Clinic Lerner Research Institute, Cleveland, Ohio 44195, USA.
Waitkus
Matthew
M
Kinney
Corttrell M
CM
Walters-Stewart
Alicia
A
DiCorleto
Paul E
PE
D000818:Animals; D001483:Base Sequence; D002465:Cell Movement / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004357:Drug Synergism; D054638:Dual Specificity Phosphatase 1 / Q000096:biosynthesis* / Q000235:genetics; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism; D004790:Enzyme Induction / Q000187:drug effects; D004815:Epidermal Growth Factor / Q000008:administration & dosage*; D066246:ErbB Receptors / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000008:administration & dosage; D006801:Humans; D007700:Kinetics; D051379:Mice; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D044463:Receptor, PAR-1 / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D013917:Thrombin / Q000008:administration & dosage*; D015533:Transcriptional Activation / Q000187:drug effects; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism*
D018841:HSP90 Heat-Shock Proteins; D012333:RNA, Messenger; D044463:Receptor, PAR-1; C547760:TRAP-1 protein, mouse; C092306:TRAP1 protein, human; D004815:Epidermal Growth Factor; C512478:EGFR protein, human; C541485:EGFR protein, mouse; D066246:ErbB Receptors; D040301:Vascular Endothelial Growth Factor Receptor-2; C517019:DUSP1 protein, human; D054638:Dual Specificity Phosphatase 1; C517020:Dusp1 protein, mouse; D013917:Thrombin