Binding of Anti-GRP78 Autoantibodies to Cell Surface GRP78 Increases Tissue Factor Procoagulant Activity via the Release of Calcium from Endoplasmic Reticulum Stores*

The increased risk of venous thromboembolism in cancer patients has been attributed to enhanced tissue factor (TF) procoagulant activity (PCA) on the surface of cancer cells. Recent studies have shown that TF PCA can be modulated by GRP78, an endoplasmic reticulum (ER)-resident molecular chaperone. In this study, we investigated the role of cell surface GRP78 in modulating TF PCA in several human cancer cell lines. Although both GRP78 and TF …