Inhibition of 5'-chloro-5'-deoxyadenosine on phosphoinositide and protein phosphorylation in swine platelets.
OBJECTIVE
To study the effects of adenosine on the phosphorylation of phosphoinositides and proteins in platelets.


METHODS
In the presence of Mg2+ and/or Ca2+, swine thrombocytic membranes were incubated with [gamma-32P]ATP at 30 degrees C for 3 min and the incorporations of 32P into phospholipids or proteins were measured.


RESULTS
5'-Chloro-5'-deoxyadenosine decreased the formation of phosphatidylinositol 4-phosphate and phosphatidylinositol 4, 5-bisphosphate [IC50 71 and 75 (95% confidence limits 60-85 and 62-90) mumol.L-1, respectively], behaving as a competitive inhibitor to ATP, and inhibited the phosphorylation of pleckstrin (the major protein kinase C substrate) and myosin light chain [IC50 75 and 82 (95% confidence limits 62-90 and 66-102) mumol.L-1, respectively].


CONCLUSIONS
Adenosine affects the phosphoinositide signaling pathway in platelets, which helps to clarify the inhibition of adenosine on platelet activation.
Ding
K H
KH
Department of Biochemistry, Guangdong Medical College, Zhanjiang, China.
Liang
N C
NC
D000818:Animals; D001792:Blood Platelets / Q000378:metabolism*; D001798:Blood Proteins / Q000378:metabolism*; D017338:Cladribine / Q000494:pharmacology*; D018994:Myosin Light Chains; D009218:Myosins / Q000378:metabolism; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates / Q000096:biosynthesis*; D010750:Phosphoproteins; D010766:Phosphorylation / Q000187:drug effects; D013552:Swine
D001798:Blood Proteins; D018994:Myosin Light Chains; D019269:Phosphatidylinositol 4,5-Diphosphate; D018129:Phosphatidylinositol Phosphates; D010750:Phosphoproteins; C076659:myosin light chain I; C037178:phosphatidylinositol 4-phosphate; C039077:platelet protein P47; D017338:Cladribine; C044739:5'-chloro-5'-deoxyadenosine; D009218:Myosins