| First Author | Zhou J | Year | 2022 |
| Journal | Blood | Volume | 139 |
| Issue | 13 | Pages | 2050-2065 |
| PubMed ID | 34752599 | Mgi Jnum | J:335385 |
| Mgi Id | MGI:7432440 | Doi | 10.1182/blood.2021012055 |
| Citation | Zhou J, et al. (2022) A novel role for endoplasmic reticulum protein 46 (ERp46) in platelet function and arterial thrombosis in mice. Blood 139(13):2050-2065 |
| abstractText | Although several members of protein disulfide isomerase (PDI) family support thrombosis, other PDI family members with the CXYC motif remain uninvestigated. ERp46 has 3 CGHC redox-active sites and a radically different molecular architecture than other PDIs. Expression of ERp46 on the platelet surface increased with thrombin stimulation. An anti-ERp46 antibody inhibited platelet aggregation, adenosine triphosphate (ATP) release, and alphaIIbbeta3 activation. ERp46 protein potentiated alphaIIbbeta3 activation, platelet aggregation, and ATP release, whereas inactive ERp46 inhibited these processes. ERp46 knockout mice had prolonged tail-bleeding times and decreased platelet accumulation in thrombosis models that was rescued by infusion of ERp46. ERp46-deficient platelets had decreased alphaIIbbeta3 activation, platelet aggregation, ATP release, and P-selectin expression. The defects were reversed by wild-type ERp46 and partially reversed by ERp46 containing any of the 3 active sites. Platelet aggregation stimulated by an alphaIIbbeta3-activating peptide was inhibited by the anti-ERp46 antibody and was decreased in ERp46-deficient platelets. ERp46 bound tightly to alphaIIbbeta3 by surface plasmon resonance but poorly to platelets lacking alphaIIbbeta3 and physically associated with alphaIIbbeta3 upon platelet activation. ERp46 mediated clot retraction and platelet spreading. ERp46 more strongly reduced disulfide bonds in the beta3 subunit than other PDIs and in contrast to PDI, generated thiols in beta3 independently of fibrinogen. ERp46 cleaved the Cys473-Cys503 disulfide bond in beta3, implicating a target for ERp46. Finally, ERp46-deficient platelets have decreased thiols in beta3, implying that ERp46 cleaves disulfide bonds in platelets. In conclusion, ERp46 is critical for platelet function and thrombosis and facilitates alphaIIbbeta3 activation by targeting disulfide bonds. |
