Open AccessDiastereomers of adenosine 3′,5′‐monothionophosphate (cAMP[S] antagonize the activation of cGMP‐dependent protein kinase
Author(s) -
HOFMANN Franz,
GENSHEIMER HansPeter,
LANDGRAF Wolfgang,
HULLIN Roger,
JASTORFF Bernd
Publication year - 1985
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1111/j.1432-1033.1985.tb08991.x
Subject(s) - autophosphorylation , protein kinase a , adenosine , pde10a , cgmp dependent protein kinase , phosphorylation , kinase , biochemistry , phosphodiesterase 3 , creb1 , chemistry , microbiology and biotechnology , biology , cyclin dependent kinase 2 , enzyme , creb , phosphodiesterase , transcription factor , gene
cGMP‐dependent protein kinase contains four cGMP‐binding sites which are homologeous to the four cAMP‐binding sites of cAMP‐dependent protein kinase. The interaction of the diastereomers of adenosine 3′,5′‐thionophosphate, (P S )‐cAMP[S] and (P R )‐cAMP[S], with cGMP‐dependent protein kinase has been studied. 1. Autophosphorylation of cGMP‐dependent protein kinase is stimulated by cAMP and (P S )‐cAMP[S] with apparent K A values of 7 μM and 94 μM, respectively. 2. cAMP‐stimulated autophosphorylation is inhibited competitively by (P R )‐cAMP[S] with a K i value of 15 μM. 3. The phosphorylation of the peptide substrate (Leu‐Arg‐Arg‐Ala‐Ser‐Leu‐Gly) is stimulated by cGMP (approx. K A 1 μM) and cAMP (approx. K A 98 μM) but neither by the (P R ) nor (P S ) stereomer of cAMP[S]. 4. (P R )‐cAMP[S] and (P S )‐cAMP[S] inhibit competitively cAMP‐ or cGMP‐stimulated phosphorylation of the peptide substrate with K i values of 52 μM and 73 μM, respectively. 5. (P S )‐cAMP[S] stimulates the phosphorylation of the peptide substrate by an autophosphorylated enzyme. 6. Binding of [ 3 H]cGMP to cGMP‐dependent protein kinase is inhibited by (P S )‐cAMP[S] and (P R )‐cAMP[S] with IC 50 values of 200 μM and 15 μM, respectively. 7. These results show that both diasteromers of cAMP[S] bind to cGMP‐dependent protein kinase. (P R )‐cAMP[S] has properties of a pure antagonist whereas (P S )‐cAMP[S] has properties of a partial agonist. The results provide further evidence that autophosphorylation of the enzyme affects the interaction between the cGMP‐binding sites and the catalytic center of the enzyme by facilitating the activation of the phosphotransferase reaction.