Enhancement of protein S anticoagulant function by beta2-glycoprotein I, a major target antigen of antiphospholipid antibodies: beta2-glycoprotein I interferes with binding of protein S to its serum inhibitor, C4b-binding protein - Merrill, JT; Zhang, HW; Shen, C; Butman, BT; Jeffries, EP; Lahita, RG; Myone, BL (Thromb Haemost, 1999)