Abstract
Abstract 27: Dok-1 Negatively Regulates Integrin aIIbß3 Outside-in Signaling and Inhibits Thrombosis
Arteriosclerosis, thrombosis, and vascular biology, Vol.33(suppl_1)
05/2013
DOI: 10.1161/atvb.33.suppl_1.A27
Abstract
Background
Platelet agonists activate integrin αIIbβ3 to allow the binding of soluble fibrinogen (a process known as inside-out signaling). Subsequent platelet aggregation leads to αIIbβ3 outside-in signaling, which results in tyrosine phosphorylation of β3 and other proteins, cytoskeletal reorganization, and platelet spreading. It has been reported that the adapter protein Dok-1 binds to the cytoplasmic tail of β3 and inhibits αIIbβ3 activation, but the specific role of Dok-1 in regulating inside-out or outside-in platelet signaling remains undefined.
Methods
We assessed the effects of Dok-1 on platelet signaling and thrombosis in Dok-1 null (Dok-1-/-) mice. Inside-out signaling was assessed by measuring αIIbβ3 activation (using the JON/A antibody) and fibrinogen binding by flow cytometry after stimulation of platelets with thrombin, ADP, and/or the thromboxane A2 receptor agonist
U46619.
Outside-in signaling was examined by measuring platelet spreading and clot retraction. Tail-transection bleeding time and susceptibility to thrombotic occlusion of the carotid artery in response to photochemical injury (rose bengal) were also measured.
Results
No significant differences in JON/A or fibrinogen binding were detected between wild-type (Dok-1+/+) and Dok-1-/- platelets, suggesting that Dok-1 does not regulate inside-out signaling. In contrast, Dok-1-/- platelets exhibited increased clot retraction and enhanced spreading on fibrinogen upon thrombin stimulation compared to Dok-1+/+ platelets (P<0.05), suggesting that Dok-1 negatively regulates outside-in signaling. Compared with Dok-1+/+ mice, Dok-1-/- mice had shorter bleeding times (181±168 vs. 379±193 seconds; P<0.001) and Dok-1-/- mice had shorter times to stable occlusion times of the carotid artery after photochemical injury compared with Dok-1+/+ mice (16.4±6.1 vs. 25.0±8.1 minutes; P<0.05).
Conclusions
The adaptor protein Dok-1 functions to negatively regulate integrin αIIbβ3 outside-in signaling. Deficiency of Dok-1 results in a prothrombotic phenotype, with shorten bleeding times and enhanced arterial thrombosis.
Details
- Title: Subtitle
- Abstract 27: Dok-1 Negatively Regulates Integrin aIIbß3 Outside-in Signaling and Inhibits Thrombosis
- Creators
- Masaru Niki - University of IowaHong Jin - University of IowaAnil K Chauhan - University of IowaSteven R Lentz - University of Iowa
- Resource Type
- Abstract
- Publication Details
- Arteriosclerosis, thrombosis, and vascular biology, Vol.33(suppl_1)
- DOI
- 10.1161/atvb.33.suppl_1.A27
- ISSN
- 1079-5642
- eISSN
- 1524-4636
- Language
- English
- Date published
- 05/2013
- Academic Unit
- Hematology, Oncology, and Blood & Marrow Transplantation; Internal Medicine
- Record Identifier
- 9984361733502771
Metrics
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