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Receptor‐regulated formation of GTP[γS] with subsequent persistent G s ‐protein activation in membranes of human platelets
Author(s) -
Wieland Thomas,
Jakobs Karl H.
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)80219-4
Subject(s) - gtp' , adenylate kinase , stimulation , chemistry , creatine , creatine kinase , g protein , membrane , guanosine triphosphate , agonist , cyclase , receptor , biochemistry , platelet , endocrinology , medicine , biology , enzyme
Preincubation of human platelet membranes with the ATP analog ATP[γS] led to persistent adenylate cyclase activation. This stimulation was increased by copreincubation with PGE 1 and obliterated by removing endogenous GDP by the NTP‐regenerating system, creatine phosphate plus creatine kinase. PGE 1 partially reversed the action of the regenerating system. Control formation of GTP[γS] from ATP[γS] and GDP in platelet membranes was apparently not stimulated by PGE 1 . In contrast, in the presence of creatine phosphate plus creatine kinase, which prevented formation of GTP[γS], PGE 1 stimulated formation of this GTP analog, by partially reversing the action of the NTP‐regenerating system. The data indicate that GTP[γS] can be formed by a membrane‐associated nucleoside diphosphokinase from ATP[γS] and GDP, resulting in persistent G s ‐protein activation, and that this process can be stimulated by an agonist‐activated receptor.