Oxidative stressors such as
hydrogen peroxide control the activation of many interconnected signaling systems and are implicated in
neurodegenerative disease etiology. Application of
hydrogen peroxide to PC12 cells activated multiple
tyrosine kinases (c-Src,
epidermal growth factor receptor (EGFR), and Pyk2) and the
serine-threonine kinase ERK1/2.
Peroxide-induced ERK1/2 activation was sensitive to intracellular
calcium chelation and EGFR and
c-Src kinase inhibition. Acute application and removal of
peroxide allowed ERK1/2 activity levels to rapidly subside to basal serum-deprived levels. Using this protocol, we demonstrated that ERK1/2 activation tachyphylaxis developed upon repeated
peroxide exposures. This tachyphylaxis was independent of c-Src/Pyk2
tyrosine phosphorylation but was associated with a progressive reduction of
peroxide-induced EGFR
tyrosine phosphorylation, EGFR interaction with
growth factor receptor binding protein 2, and a redistribution of EGFR from the plasma membrane to the cytoplasm. Our data indicates that components of
peroxide-induced ERK1/2 cascades are differentially affected by repeated exposures, indicating that oxidative signaling may be contextually variable.