Photoaffinity labeling of integrin alpha IIb beta 3 (glycoprotein IIb-IIIa) on intact platelets with 8-azido-[gamma-32P]ATP. |
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| Authors: | P Mayinger M Gawaz |
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| Institution: | Medizinische Klinik I, Klinikum Grosshadern, Ludwig-Maximilians Universit?t München, Germany. |
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| Abstract: | The fibrinogen receptor GPIIb-IIIa plays a crucial role in platelet aggregation. Here we show that the adenine nucleotide, 8-azido-ATP, inhibits ADP-induced conformational change of the platelet fibrinogen receptor GPIIb-IIIa (integrin alpha IIb beta 3). Photoaffinity labeling of intact platelets with 8-azido-gamma-32P]ATP exclusively modifies two plasma-membrane glycoproteins which are identical with both subunits of GPIIb-IIIa. The presence of adenine-nucleotide-binding sites on GPIIb-IIIa implies that the platelet fibrinogen receptor is directly regulated by extracellular adenine nucleotides. |
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