Direct evidence for the interaction of the nucleotide affinity analog
5'-p-fluorosulfonylbenzoyl adenosine with a platelet ADP receptor
WR Figures, LM Scearce, P DeFeo, G Stewart, F Zhou, J Chen, J Daniel, RF Colman and RW Colman
Previous reports have indicated that the nucleotide affinity analog 5'-
p-fluorosulfonylbenzoyl adenosine (FSBA) at concentrations between 40 and
100 mumol/L and at times greater than 20 minutes covalently modifies a
single protein component on the external platelet membrane surface and that
adenosine diphosphate (ADP) protects against this reaction. That this
protein is an ADP receptor linked to platelet activation is shown by FSBA
inhibition of ADP-mediated platelet shape change, aggregation, and
fibrinogen receptor exposure. In this report, further evidence for the
interaction of FSBA with the ADP receptor on platelets is provided by the
observation that FSBA at high concentrations (100 to 500 mumol/L) behaves
as a weak agonist to produce platelet shape change within one minute as
detected by spectroscopic assay and scanning electron microscopy with
concomitant phosphorylation of the light chain of platelet myosin. The
specificity of FSBA as an agonist is demonstrated by inhibition of
FSBA-induced shape change by ATP and the covalent incorporation of SBA as
well as the failure of 5'-fluorosulfonylbenozoyl guanosine (FSBG) to cause
shape change. In contrast, incubation of platelets with low concentrations
of [3H]-FSBA (40 mol/L) is not associated with stimulation of platelet
shape change or myosin light chain phosphorylation.
Volume 70,
Issue 3,
pp. 796-803,
09/01/1987
Copyright © 1987 by The American Society of Hematology
