Effect of cyclic AMP on human blood platelets: induction of pseudopod formation and protein phosphorylation.
A variety of techniques, including immunofluorescence, electron microscopy and biochemical analysis, were used to examine shape changes and cytoskeletal reorganization of human blood platelets during treatment with N6,O2-dibutyryl adenosine 3',5'-cyclic monophosphoric acid (dbcAMP), and agent known to elevate the intracellular level of cyclic AMP (cAMP). Cytochemical analysis shows that the unstimulated platelets have a discoid shape with no obvious membrane projections. Platelets treated with dbcAMP produce pseudopod-like structures containing cytoskeletal proteins such as actin and microtubules. Biochemical analysis reveals that a 125,000 dalton phosphoprotein (P-125) is preferentially recruited into cytoskeletal fractions of platelets treated with dbcAMP. This protein, which is one of the substrates for cAMP-dependent kinase(s) and/or is closely associated with the cytoskeleton, may play an important role in regulating the shape changes and cytoskeletal reorganization that occur during the early stages of platelet activation.
Maurer
D R
DR
Department of Anatomy and Cell Biology, School of Medicine, University of Miami, Florida 33101.
Majercik
M H
MH
Bourguignon
L Y
LY
D001792:Blood Platelets / Q000032:analysis / Q000187:drug effects* / Q000648:ultrastructure; D001798:Blood Proteins / Q000032:analysis / Q000378:metabolism*; D003994:Bucladesine / Q000494:pharmacology*; D003598:Cytoskeletal Proteins / Q000032:analysis; D006801:Humans; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D010750:Phosphoproteins / Q000378:metabolism*; D010766:Phosphorylation; D011554:Pseudopodia / Q000648:ultrastructure*
D001798:Blood Proteins; D003598:Cytoskeletal Proteins; D010750:Phosphoproteins; D003994:Bucladesine