Characterization of the gene encoding mouse platelet glycoprotein Ibβ

Platelet glycoprotein (GP) Ib/IX/V complex is a major receptor for von Willebrand factor (vWF), which mediates platelet adhesion and aggregation under high shear stress conditions. It is composed of GPIbα, GPIbβ, GPIX, and GPV. All subunits for the human receptor have been cloned and characterized. However, the function of GPIbβ is still elusive. To obtain further information of GPIbβ, we have determined the genomic sequence of mouse GPIbβ (1466 bp). The deduced amino acid sequence (206aa) was 88% identical to the human GPIbβ protein. All cysteine residues, putative N- linked glycosylation site (Asn41), and putative phosphorylation site (Ser166) were conserved. The promoter region contained putative GATA and ets binding motif implicated in megakaryocytic expression. Mouse GPIbβ also contained a leucine-rich glycoprotein (LRG) sequence of 24 amino acids same as human GPIbβ.