Thromb Haemost 2025; 125(08): 779-790
DOI: 10.1055/a-2442-9031
Cellular Haemostasis and Platelets

Distinct Role of GRK3 in Platelet Activation by Desensitization of G Protein-Coupled Receptors

Preeti K. Chaudhary
1   Laboratory of Veterinary Pathology and Platelet Signaling, College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea
,
Sanggu Kim
1   Laboratory of Veterinary Pathology and Platelet Signaling, College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea
,
Satya P. Kunapuli
2   Sol Sherry Thrombosis Research Center and Department of Cardiovascular Sciences, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania, United States
,
Soochong Kim
1   Laboratory of Veterinary Pathology and Platelet Signaling, College of Veterinary Medicine, Chungbuk National University, Cheongju, Republic of Korea
› Author Affiliations

Funding This research was funded by the Chungbuk National University BK21 program (2024), the National Research Foundation (NRF) of Korea (NRF-2022R1A2C1003638), and the Basic Research Laboratory Program (2022R1A4A1025557) through the NRF of Korea funded by the Ministry of Science and ICT.


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Abstract

Background

Many platelet agonists mediate their cellular effects through G protein-coupled receptors (GPCRs) to induce platelet activation, and GPCR kinases (GRKs) have been demonstrated to have crucial roles in most GPCR functions in other cell types. Here, we investigated the functional role of GRK3 and the molecular basis for the regulation of GPCR desensitization by GRK3 in platelets.

Methods

We used mice lacking GRK3 as well as β-arrestin2, which has been shown to be important in GPCR function in platelets.

Results

Platelet aggregation and dense granule secretion induced by 2-MeSADP, U46619, thrombin, and AYPGKF were significantly potentiated in both GRK3 −/− and β-arrestin2 −/− platelets compared with wild-type (WT) platelets, whereas non-GPCR agonist collagen-induced platelet aggregation and secretion were not affected. We have previously shown that GRK6 is not involved in the regulation of Gq-coupled 5HT2A and Gz-coupled α2A adrenergic receptors. Interestingly, in contrast to GRK6, platelet aggregation induced by costimulation of serotonin and epinephrine, which activate 5-HT2A and α2A adrenergic receptors, respectively, was significantly potentiated in GRK3 −/− platelets, suggesting that GRK3 is involved in general GPCR regulation. In addition, platelet aggregation in response to the second challenge of adenosine diphosphate was restored in GRK3 −/− platelets, whereas restimulation of the agonist failed to induce aggregation in WT platelets, confirming that GRK3 contributes to general GPCR desensitization. Furthermore, 2-MeSADP- and AYPGKF-induced AKT and ERK phosphorylation were significantly potentiated in GRK3 −/− platelets. Finally, GRK3 −/− mice showed shorter tail bleeding times compared with WT, indicating that GRK3 −/− mice is more susceptible to hemostasis.

Conclusion

GRK3 plays a crucial role in the regulation of platelet activation through general GPCR desensitization in platelets.

Authors' Contribution

Conceptualization, P.K.C. and S.K. (Soochong Kim); methodology, P.K.C. and S.K. (Sanggu Kim); validation, S.P.K. and S.K. (Soochong Kim); investigation, P.K.C. and S.K. (Soochong Kim); writing—original draft, P.K.C.; writing—review and editing, P.K.C., S.K. (Sanggu Kim), S.P.K., and S.K. (Soochong Kim); supervision, S.K. (Soochong Kim). All the authors have read and agreed to the published version of the manuscript.




Publication History

Received: 03 June 2024

Accepted: 16 October 2024

Accepted Manuscript online:
17 October 2024

Article published online:
11 November 2024

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