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Bye et al Science Signaling accepted 2 Jan 2020.pdf (2.57 MB)

Ca2+ waves coordinate purinergic receptor–evoked integrin activation and polarization

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journal contribution
posted on 2020-02-04, 15:23 authored by Alexander Bye, Jonathan Gibbins, Martyn Mahaut-Smith
Cells sense extracellular nucleotides through the P2Y class of purinergic G protein–coupled receptors (GPCRs), which stimulate integrin activation through signaling events, including intracellular Ca2+ mobilization. We investigated the relationship between P2Y-stimulated repetitive Ca2+ waves and fibrinogen binding to the platelet integrin αIIbβ3 (GPIIb/IIIa) through confocal fluorescence imaging of primary rat megakaryocytes. Costimulation of the receptors P2Y1 and P2Y12 generated a series of Ca2+ transients that each induced a rapid, discrete increase in fibrinogen binding. The peak and net increase of individual fibrinogen binding events correlated with the Ca2+ transient amplitude and frequency, respectively. Using BAPTA loading and selective receptor antagonists, we found that Ca2+ mobilization downstream of P2Y1 was essential for ADP-evoked fibrinogen binding, whereas P2Y12 and the kinase PI3K were also required for αIIbβ3 activation and enhanced the number of Ca2+ transients. ADP-evoked fibrinogen binding was initially uniform over the cell periphery but subsequently redistributed with a polarity that correlated with the direction of the Ca2+ waves. Polarization of αIIbβ3 may be mediated by the actin cytoskeleton, because surface-bound fibrinogen is highly immobile, and its motility was enhanced by cytoskeletal disruption. In conclusion, spatial and temporal patterns of Ca2+ increase enable fine control of αIIbβ3 activation after cellular stimulation. P2Y1-stimulated Ca2+ transients coupled to αIIbβ3 activation only in the context of P2Y12 coactivation, thereby providing an additional temporal mechanism of synergy between these Gq- and Gi-coupled GPCRs.

History

Citation

Science Signaling 21 Jan 2020: Vol. 13, Issue 615, eaav7354

Author affiliation

Department of Molecular and Cell Biology

Version

  • AM (Accepted Manuscript)

Published in

Science Signaling

Volume

13

Issue

615

Pagination

eaav7354

Publisher

American Association for the Advancement of Science

issn

1945-0877

eissn

1937-9145

Acceptance date

2020-01-02

Copyright date

2020

Publisher version

https://stke.sciencemag.org/content/13/615/eaav7354

Language

en

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