Antagonistic effect of EGF on FAK phosphorylation/dephosphorylation in a cell.
Focal adhesion kinase (FAK) plays a key role in the crosstalk of growth factor- and cell adhesion-mediated signaling pathway. In this study, we found that the quantitative change of phosphorylated FAK was bell-shaped time-dependently by EGF stimulation in immortalized human keratinocyte (HaCaT). EGF enhanced FAK phosphorylation and cell spreading in adhering HaCaT cells with low-phosphorylated FAK. On the other hand, spread HaCaT cells having high-phosphorylated FAK changed to round shapes with FAK dephosphorylation 15 min after EGF stimulation. Pharmacological agents, U0126 and PD98059 (mitogen-activated protein kinases (MAPK) kinases (MEK) inhibitors), and AG1478 (an EGF receptor kinase inhibitor) blocked the cell rounding and FAK dephosphorylation. In addition, the EGFR-MAPK signaling pathway had an influence on cell migration by regulating FAK dephosphorylation of keratinocytes in response of EGF, since the MEK inhibitors and AG1478 suppressed EGF-induced cell migration. However, FAK phosphorylation and HaCaT cell spreading were inhibited only by the antagonist of EGF-EGFR binding but not by the MEK inhibitors and AG1478. Taken together, we suggest that EGF is antagonistically involved in both FAK phosphorylation and dephosphorylation with different mechanisms in a cell.
Kim
Sang-Heon
SH
Biomaterial Research Center, Division of Life Sciences, Korea Institute of Science and Technology, Seoul, Korea. skimbrc@kist.re.kr
Kim
Soo Hyun
SH
D002448:Cell Adhesion / Q000502:physiology; D002460:Cell Line; D002465:Cell Movement / Q000502:physiology; D004815:Epidermal Growth Factor / Q000502:physiology*; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D006801:Humans; D015603:Keratinocytes / Q000166:cytology / Q000201:enzymology* / Q000378:metabolism; D010766:Phosphorylation
D004815:Epidermal Growth Factor; D051416:Focal Adhesion Protein-Tyrosine Kinases