Lh. Lin et al., INHIBITION OF PROTEIN KINASE-C-MEDIATED AND CASEIN KINASE-II-MEDIATEDPHOSPHORYLATION OF GAP-43 BY S100-BETA, Molecular brain research, 25(3-4), 1994, pp. 297-304
The effect of the glial-derived protein, S100 beta, on the in vitro ph
osphorylation of the growth-associated protein GAP-43 was investigated
. S100 beta inhibited in a dose dependent manner the phosphorylation o
f GAP-43 by protein kinase C (PKC) or by casein kinase II (CKII). S100
beta appeared to slow down the rate and the degree to which GAP-43 ca
n be phosphorylated by either kinase. The specificity of the inhibitio
n was demonstrated by the observation that the phosphorylation of two
other CKII substrates, casein and a selective peptide substrate, was n
ot inhibited by S100 beta. The marked inhibitory effect of S100 beta r
equired the presence of calcium in the phosphorylation reactions. In a
ddition, S100 beta inhibition of GAP-43 phosphorylation was seen with
GAP-43 purified under a variety of conditions that alter acylation, su
ggesting that the acylation state of GAP-43 does not affect the abilit
y of S100 beta to modulate CKII- or PKC-mediated phosphoryation of GAP
-43.