Glycoprotein Ib (GPIb), also known as CD42, is a component of the GPIb-V-IX complex on

platelets Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby ini ...

. The GPIb-V-IX complex binds

von Willebrand factor Von Willebrand factor (VWF) () is a blood glycoprotein involved in hemostasis, specifically, platelet adhesion. It is deficient and/or defective in von Willebrand disease and is involved in many other diseases, including thrombotic thrombocytopen ...

, allowing

platelet adhesion Platelets, also called thrombocytes (from Greek θρόμβος, "clot" and κύτος, "cell"), are a component of blood whose function (along with the coagulation factors) is to react to bleeding from blood vessel injury by clumping, thereby ini ...

and

platelet plug The platelet plug, also known as the hemostatic plug or platelet thrombus, is an aggregation of platelets formed during early stages of hemostasis in response to one or more injuries to blood vessel walls. After platelets are recruited and begin to ...

formation at sites of vascular injury. It is deficient in the

Bernard–Soulier syndrome Bernard–Soulier syndrome (BSS) is a rare autosomal recessive bleeding disorder that is caused by a deficiency of the ''glycoprotein Ib-IX-V complex'' (GPIb-IX-V), the receptor for von Willebrand factor. The incidence of BSS is estimated to be ...

. A

gain-of-function mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mitos ...

causes platelet-type

von Willebrand disease Von Willebrand disease (VWD) is the most common hereditary blood-clotting disorder in humans. An acquired form can sometimes result from other medical conditions. It arises from a deficiency in the quality or quantity of von Willebrand factor ( ...

.McPherson & Pincus: ''Henry's Clinical Diagnosis and Management by Laboratory Methods'', 21st ed., pp. 760–2 (W. B. Saunders, 2006). Autoantibodies against Ib/IX can be produced in

immune thrombocytopenic purpura Immune thrombocytopenic purpura (ITP), also known as idiopathic thrombocytopenic purpura or immune thrombocytopenia, is a type of thrombocytopenic purpura defined as an isolated low platelet count with a normal bone marrow in the absence of othe ...

. Components include

GP1BA Platelet glycoprotein Ib alpha chain also known as glycoprotein Ib (platelet), alpha polypeptide or CD42b (Cluster of Differentiation 42b), is a protein that in humans is encoded by the ''GP1BA'' gene. Function Glycoprotein Ib (GP Ib) is a pla ...

and

GP1BB Glycoprotein Ib (platelet), beta polypeptide (GP1BB) also known as CD42c (Cluster of Differentiation 42c), is a protein that in humans is encoded by the GP1BB gene. Function Platelet glycoprotein Ib (GPIb) is a heterodimeric transmembrane prote ...

. It complexes with

Glycoprotein IX Glycoprotein IX (platelet) (GP9) also known as CD42a (Cluster of Differentiation 42a), is a human gene. Platelet glycoprotein IX (GP9) is a small membrane glycoprotein found on the surface of human platelets. It forms a 1-to-1 noncovalent complex ...

References

External links

* Glycoproteins {{protein-stub