| First Author | Naik MU | Year | 2012 |
| Journal | Blood | Volume | 119 |
| Issue | 14 | Pages | 3352-60 |
| PubMed ID | 22271446 | Mgi Jnum | J:183816 |
| Mgi Id | MGI:5319296 | Doi | 10.1182/blood-2011-12-397398 |
| Citation | Naik MU, et al. (2012) JAM-A protects from thrombosis by suppressing integrin alphaIIbbeta3-dependent outside-in signaling in platelets. Blood 119(14):3352-60 |
| abstractText | Mounting evidence suggests that agonist-initiated signaling in platelets is closely regulated to avoid excessive responses to injury. A variety of physiologic agonists induce a cascade of signaling events termed as inside-out signaling that culminate in exposure of high-affinity binding sites on integrin alpha(IIb)beta(3). Once platelet activation has occurred, integrin alpha(IIb)beta(3) stabilizes thrombus formation by providing agonist-independent "outside-in" signals mediated in part by contractile signaling. Junctional adhesion molecule A (JAM-A), a member of the cortical thymocyte marker of the Xenopus (CTX) family, was initially identified as a receptor for a platelet stimulatory mAb. Here we show that JAM-A in resting platelets functions as an endogenous inhibitor of platelet function. Genetic ablation of Jam-A in mice enhances thrombotic function of platelets in vivo. The absence of Jam-A results in increase in platelet aggregation ex vivo. This gain of function is not because of enhanced inside-out signaling because granular secretion, Thromboxane A2 (TxA2) generation, as well as fibrinogen receptor activation, are normal in the absence of Jam-A. Interestingly, integrin outside-in signaling such as platelet spreading and clot retraction is augmented in Jam-A-deficient platelets. We conclude that JAM-A normally limits platelet accumulation by inhibiting integrin outside-in signaling thus preventing premature platelet activation. |
