Platelet activation results in the relocation of the thiol isomerase enzyme ERp57 to the platelet surface where it binds to the β₃ integrin subunit. The absence of ERp57 protein, or inhibition of its activity, results in diminished platelet activation, aggregation, and recruitment into a growing thrombus. Because integrin α_IIbβ₃ activation, which is necessary for fibrinogen binding, is associated with disulfide rearrangement, this suggests ERp57 may contribute to its activation or stabilization in a conformation that is able to bind to fibrinogen.