The G-protein subunits regulate platelet function. Academic Article uri icon


  • AIMS: G-protein coupled receptors (GPCRs) tightly regulate platelet function by interacting with various physiological agonists. An essential mediator of GPCR signaling is the G protein heterotrimers, in which the subunits are central players in downstream signaling. Herein, we investigated the role of G subunits in platelet function, hemostasis and thrombogenesis. METHODS: To achieve this goal, platelets from both mice and humans were employed in the context of a small molecule inhibitor of G, namely gallein. We used an aggregometer to examine aggregation and dense granules secretion. We also used flow cytometry for P-selectin and PAC1 to determine the impact of inhibiting G on -granule secretion and IIb3 activation. Clot retraction and the platelet spreading assay were used to examine G role in outside-in platelet signaling, whereas Western blot was employed to examine its role in Akt activation. Finally, we used the bleeding time assay and the FeCl3-induced carotid-artery injury thrombosis model to determine G contribution to in vivo platelet function. RESULTS: We observed that gallein inhibits platelet aggregation and secretion in response to agonist stimulation, in both mouse and human platelets. Furthermore, gallein also exerted inhibitory effects on integrin IIb3 activation, clot retraction, platelet spreading and Akt activation/phosphorylation. Finally, gallein's inhibitory effects manifested in vivo, as documented by its ability to modulate physiological hemostasis and delay thrombus formation. CONCLUSION: Our findings demonstrate, for the first time, that G subunits directly regulate GPCR-dependent platelet function, in vitro and in vivo. Moreover, these data highlight G as a novel therapeutic target for managing thrombotic disorders.

published proceedings

  • Life Sci

altmetric score

  • 1.25

author list (cited authors)

  • Alarabi, A. B., Karim, Z. A., Hinojos, V., Lozano, P. A., Hernandez, K. R., Montes Ramirez, J. E., ... Alshbool, F. Z.

citation count

  • 1

complete list of authors

  • Alarabi, Ahmed B||Karim, Zubair A||Hinojos, Victoria||Lozano, Patricia A||Hernandez, Keziah R||Montes Ramirez, Jean E||Ali, Hamdy EA||Khasawneh, Fadi T||Alshbool, Fatima Z

publication date

  • January 2020