J. Elbenna et al., ACTIVATION OF P38 IN STIMULATED HUMAN NEUTROPHILS - PHOSPHORYLATION OF THE OXIDASE COMPONENT P47(PHOX) BY P38 AND ERK BUT NOT BY JNK, Archives of biochemistry and biophysics, 334(2), 1996, pp. 395-400
Incubation of human neutrophils with FMLP, a chemotactic peptide, or P
MA, a stimulator of protein kinase C, resulted in the activation of p3
8, a proline-directed kinase. Previous studies had shown that extracel
lular signal-regulated kinase (ERK), another proline-directed kinase,
was activated with similar kinetics in neutrophils stimulated with FML
P and PMA (1, 2). Because one possible target for these proline-direct
ed kinases is p47(phox), a component of the respiratory burst oxidase,
we examined the phosphorylation of this protein by p38 and ERK, as we
ll as JNK, another proline-directed kinase present in neutrophils. We
found that both p38 and ERK phosphorylated p47(phox) at the same site
and at similar rates, but that p47(phox) was not a substrate for JNK.
These data show that p38, like ERK, can be activated in neutrophils ex
posed to an appropriate stimulus, and that some but not all proline-di
rected kinases are able to participate in the phosphorylation of a pro
tein essential for normal neutrophil function. (C) 1996 Academic Press
, Inc.