The proline-rich tyrosine kinase Pyk2 regulates platelet integrin aIIbß3 outside-in signaling
Background: The proline-rich tyrosine kinase Pyk2 is a focal adhesion kinase expressed in blood platelets, and is activated downstream of G-protein coupled receptors as well as integrin a2ß1. Objective: In this study we have investigated the involvement of Pyk2 in integrin aIIbß3 outside-in signalin...
| Main Authors: | , , , , , , , , , |
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| Format: | Journal Article |
| Published: |
2013
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| Online Access: | http://hdl.handle.net/20.500.11937/17871 |
| _version_ | 1848749582813495296 |
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| author | Cipolla, L. Consonni, A. Guidetti, G. Canobbio, I. Okigaki, M. Falasca, Marco Ciraolo, E. Hirsch, E. Balduini, C. Torti, M. |
| author_facet | Cipolla, L. Consonni, A. Guidetti, G. Canobbio, I. Okigaki, M. Falasca, Marco Ciraolo, E. Hirsch, E. Balduini, C. Torti, M. |
| author_sort | Cipolla, L. |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | Background: The proline-rich tyrosine kinase Pyk2 is a focal adhesion kinase expressed in blood platelets, and is activated downstream of G-protein coupled receptors as well as integrin a2ß1. Objective: In this study we have investigated the involvement of Pyk2 in integrin aIIbß3 outside-in signaling in human and murine platelets. Methods: We analyzed the stimulation of intracellular signaling pathways in platelets from Pyk2 knockout mice adherent to immobilized fibrinogen. Results: Pyk2 was rapidly phosphorylated and activated in human and murine platelets adherent to fibrinogen through integrin aIIbß3. Activation of Pyk2 was Src-dependent, but did not require phospholipase C?2 activity. Platelets from Pyk2 knockout mice showed a defective ability to adhere and spread on fibrinogen, in association with a dramatic reduction of phosphatidylinositol 3-kinase (PI3K) activation and Akt phosphorylation. Pharmacological and genetic analysis demonstrated that integrin aIIbß3 engagement selectively stimulated the ß-isoform of PI3K (PI3Kß), and that, as for Pyk2, PI3Kß activation required Src family kinases activity, but not phospholipase C?2. In fibrinogen-adherent platelets, both Pyk2 and PI3Kß were necessary for stimulation of the small GTPase Rap1b, a regulator of cell adhesion and spreading. Integrin aIIbß3 engagement triggered the association of the PI3Kß regulatory subunit p85 with the adaptor protein c-Cbl, which was mediated by the p85 SH3 domain, and was independent of c-Cbl tyrosine phosphorylation. However, p85-associated c-Cbl was tyrosine phosphorylated by activated Pyk2 in fibrinogen adherent platelets. Conclusions: These results identify a novel pathway of integrin aIIbß3 outside-in signaling and recognize the tyrosine kinase Pyk2 as a major regulator of platelet adhesion and spreading on fibrinogen. © 2012 International Society on Thrombosis and Haemostasis. |
| first_indexed | 2025-11-14T07:23:14Z |
| format | Journal Article |
| id | curtin-20.500.11937-17871 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:23:14Z |
| publishDate | 2013 |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-178712017-09-13T15:42:21Z The proline-rich tyrosine kinase Pyk2 regulates platelet integrin aIIbß3 outside-in signaling Cipolla, L. Consonni, A. Guidetti, G. Canobbio, I. Okigaki, M. Falasca, Marco Ciraolo, E. Hirsch, E. Balduini, C. Torti, M. Background: The proline-rich tyrosine kinase Pyk2 is a focal adhesion kinase expressed in blood platelets, and is activated downstream of G-protein coupled receptors as well as integrin a2ß1. Objective: In this study we have investigated the involvement of Pyk2 in integrin aIIbß3 outside-in signaling in human and murine platelets. Methods: We analyzed the stimulation of intracellular signaling pathways in platelets from Pyk2 knockout mice adherent to immobilized fibrinogen. Results: Pyk2 was rapidly phosphorylated and activated in human and murine platelets adherent to fibrinogen through integrin aIIbß3. Activation of Pyk2 was Src-dependent, but did not require phospholipase C?2 activity. Platelets from Pyk2 knockout mice showed a defective ability to adhere and spread on fibrinogen, in association with a dramatic reduction of phosphatidylinositol 3-kinase (PI3K) activation and Akt phosphorylation. Pharmacological and genetic analysis demonstrated that integrin aIIbß3 engagement selectively stimulated the ß-isoform of PI3K (PI3Kß), and that, as for Pyk2, PI3Kß activation required Src family kinases activity, but not phospholipase C?2. In fibrinogen-adherent platelets, both Pyk2 and PI3Kß were necessary for stimulation of the small GTPase Rap1b, a regulator of cell adhesion and spreading. Integrin aIIbß3 engagement triggered the association of the PI3Kß regulatory subunit p85 with the adaptor protein c-Cbl, which was mediated by the p85 SH3 domain, and was independent of c-Cbl tyrosine phosphorylation. However, p85-associated c-Cbl was tyrosine phosphorylated by activated Pyk2 in fibrinogen adherent platelets. Conclusions: These results identify a novel pathway of integrin aIIbß3 outside-in signaling and recognize the tyrosine kinase Pyk2 as a major regulator of platelet adhesion and spreading on fibrinogen. © 2012 International Society on Thrombosis and Haemostasis. 2013 Journal Article http://hdl.handle.net/20.500.11937/17871 10.1111/jth.12099 unknown |
| spellingShingle | Cipolla, L. Consonni, A. Guidetti, G. Canobbio, I. Okigaki, M. Falasca, Marco Ciraolo, E. Hirsch, E. Balduini, C. Torti, M. The proline-rich tyrosine kinase Pyk2 regulates platelet integrin aIIbß3 outside-in signaling |
| title | The proline-rich tyrosine kinase Pyk2 regulates platelet integrin aIIbß3 outside-in signaling |
| title_full | The proline-rich tyrosine kinase Pyk2 regulates platelet integrin aIIbß3 outside-in signaling |
| title_fullStr | The proline-rich tyrosine kinase Pyk2 regulates platelet integrin aIIbß3 outside-in signaling |
| title_full_unstemmed | The proline-rich tyrosine kinase Pyk2 regulates platelet integrin aIIbß3 outside-in signaling |
| title_short | The proline-rich tyrosine kinase Pyk2 regulates platelet integrin aIIbß3 outside-in signaling |
| title_sort | proline-rich tyrosine kinase pyk2 regulates platelet integrin aiibß3 outside-in signaling |
| url | http://hdl.handle.net/20.500.11937/17871 |