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Dok-2 adaptor protein regulates the shear-dependent adhesive function of platelet integrin ?IIb?3 in mice.


ABSTRACT: The Dok proteins are a family of adaptor molecules that have a well defined role in regulating cellular migration, immune responses, and tumor progression. Previous studies have demonstrated that Doks-1 to 3 are expressed in platelets and that Dok-2 is tyrosine-phosphorylated downstream of integrin ?IIb?3, raising the possibility that it participates in integrin ?IIb?3 outside-in signaling. We demonstrate that Dok-2 in platelets is primarily phosphorylated by Lyn kinase. Moreover, deficiency of Dok-2 leads to dysregulated integrin ?IIb?3-dependent cytosolic calcium flux and phosphatidylinositol(3,4)P2 accumulation. Although agonist-induced integrin ?IIb?3 affinity regulation was unaltered in Dok-2(-/-) platelets, Dok-2 deficiency was associated with a shear-dependent increase in integrin ?IIb?3 adhesive function, resulting in enhanced platelet-fibrinogen and platelet-platelet adhesive interactions under flow. This increase in adhesion was restricted to discoid platelets and involved the shear-dependent regulation of membrane tethers. Dok-2 deficiency was associated with an increased rate of platelet aggregate formation on thrombogenic surfaces, leading to accelerated thrombus growth in vivo. Overall, this study defines an important role for Dok-2 in regulating biomechanical adhesive function of discoid platelets. Moreover, they define a previously unrecognized prothrombotic mechanism that is not detected by conventional platelet function assays.

SUBMITTER: Hughan SC 

PROVIDER: S-EPMC3931064 | biostudies-literature | 2014 Feb

REPOSITORIES: biostudies-literature

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Dok-2 adaptor protein regulates the shear-dependent adhesive function of platelet integrin αIIbβ3 in mice.

Hughan Sascha C SC   Spring Christopher M CM   Schoenwaelder Simone M SM   Sturgeon Sharelle S   Alwis Imala I   Yuan Yuping Y   McFadyen James D JD   Westein Erik E   Goddard Duncan D   Ono Akiko A   Yamanashi Yuji Y   Nesbitt Warwick S WS   Jackson Shaun P SP  

The Journal of biological chemistry 20140102 8


The Dok proteins are a family of adaptor molecules that have a well defined role in regulating cellular migration, immune responses, and tumor progression. Previous studies have demonstrated that Doks-1 to 3 are expressed in platelets and that Dok-2 is tyrosine-phosphorylated downstream of integrin αIIbβ3, raising the possibility that it participates in integrin αIIbβ3 outside-in signaling. We demonstrate that Dok-2 in platelets is primarily phosphorylated by Lyn kinase. Moreover, deficiency of  ...[more]

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