M. Asahi et al., CYCLIC AMP-ELEVATING AGENTS NEGATIVELY REGULATE THE ACTIVATION OF P72(SYK) IN N-FORMYL-METHIONYL-LEUCYL-PHENYLALANINE RECEPTOR SIGNALING, Biochemical and biophysical research communications, 212(3), 1995, pp. 887-893
Here we investigated the involvement of the non-receptor protein-tyros
ine kinase p72(syk) in formyl methionyl-leucyl-phenylalanine (fMLP) re
ceptor signaling. The activity of p72(syk) began to rise from 15 s and
reached to maximum within 2-5 min after 5 mu M fMLP stimulation in po
rcine polymorphonuclear neutrophils (PMNs). Cyclic AMP (cAMP)-elevatin
g agents, prostaglandin E(2) (PGE(2)) and forskolin, or dibutyryl cAMP
partially suppressed p72(Syk) activities stimulated by fMLP in PMNs.
Pretreatment with an inhibitor of cAMP-dependent protein kinase abolis
hed the suppression of the fMLP-induced p72(Syk) activation by these c
AMP-elevating agents. It was also observed that cAMP-dependent protein
kinase phosphorylates p72(Syk) on serine residues in vitro. These res
ults indicate a possibility that cAMP-dependent protein kinase negativ
ely regulates the activation of p72(syk) in fMLP-receptor signaling. (
C) 1995 Academic Press, Inc.