The multisubunit leucine-rich glycoprotein (GP) Ib-IX-V complex mediates von Willebrand factor-dependent platelet adhesion at sites of blood-vessel injury. Molecular defects of this receptor are reported to cause the Bernard-Soulier haemorrhagic disorder. To gain insight into the mechanisms controlling expression of normal and defective receptors, we performed pulse-chase metabolic studies and ...

Extracellular Ca2+ is required for platelet aggregation and secretion in response to ADP or epinephrine. Recently, we reported that the platelet surface contains two classes of high affinity binding sites for extracellular Ca2+. To identify these sites and clarify their role in platelet function, we have now (a) studied platelets congenitally deficient in surface membrane glycoproteins and (b) ...

Bernard-Soulier syndrome (B-Ss) is a rare congenital bleeding disorder caused by abnormal giant platelets, thrombocytopenia, and defective glycoprotein (GP) Ib-V-IX, the adhesion receptor for von Willebrand factor (vWF). This report describes the molecular defect in two related individuals with well-established B-Ss whose platelets exhibit decreased GPIb-IX and normal GPV on their surfaces. The...

We investigated the molecular genetic and biosynthetic badeletion of the last two bases of the codon for Tyr492 (TAT). This mutation causes a frameshift that alters the GP Iba sis of Bernard-Soulier syndrome in a severely affected white woman. Flow cytometric analysis showed a severe defiamino acid sequence, beginning within its transmembrane region. The mutant polypeptide contains 81 novel ami...

Regulation of thrombopoiesis: effects of the degree of thrombocytopenia on megakaryocyte ploidy and platelet volume. Blood 1987;70:177-85. 29. Stenberg PE, Levin J. Ultrastructural analysis of acute immune thrombocytopenia in mice: dissociation between alterations in megakaryocytes and platelets. Cazenave J-P, et al. Intrinsic impaired proplatelet formation and microtubule coil assembly of mega...