Phosphorylation and activation of cGMP-dependent protein kinase by Src.
Using information obtained from experiments with peptide substrates of v-Src, a motif within the cGMP-binding domain of cGMP-dependent protein kinase (cGK) was identified as a potential phosphorylation site for v-Src. Here we show that the purified Ialpha isozyme of cGK is phosphorylated stoichiometrically and in a time-dependent manner by purified Src in vitro. The kinase activity of cGK is elevated approximately 4-fold (relative to autophosphorylated cGK) or 10-fold (relative to unphosphorylated cGK) upon tyrosine phosphorylation by Src. Phosphorylation of cGK by v-Src produces modest effects on the cGMP-binding properties and dissociation rates of cGK, and reduces the kact for cGMP. We hypothesize that the mechanism of activation may involve coupling of the cGMP binding domain to the catalytic domain.
LaFevre-Bernt
M
M
Department of Physiology and Biophysics, School of Medicine, State University of New York at Stony Brook, Stony Brook, NY 11794, USA.
Corbin
J D
JD
Francis
S H
SH
Miller
W T
WT
D006152:Cyclic GMP / Q000378:metabolism; D017869:Cyclic GMP-Dependent Protein Kinases / Q000378:metabolism*; D004789:Enzyme Activation; D015688:Oncogene Protein pp60(v-src) / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011994:Recombinant Proteins / Q000378:metabolism
D011994:Recombinant Proteins; D015688:Oncogene Protein pp60(v-src); D017869:Cyclic GMP-Dependent Protein Kinases; D006152:Cyclic GMP