G Protein and Integrin αIIbβ3 Bidirectional Signal Transduction

Integrin is a family of cell surface receptors,involving in cell-extracellular matrix,cell-cell adhesion and cell migration. Integrin αⅡbβ3( GPⅡb-Ⅲa),the most abundant membrane glycoprotein in platelets exclusively expressed in megakaryocyte / platelet lineage,mediates platelet adhesion,spread and aggregation. Heterologous trimer G protein and small G protein Rap1 are implicated in integrin αⅡbβ3 inside-out signaling and the small G proteins( Rho A,Rac,etc.) and Gα13 in outside-in signaling highlighting a critical role of G proteins in integrin α Ⅱ bβ3 bidirectional signaling. This review summarizes the domain structure,classification and molecular activities of G proteins and provides a current overview of the roles of G proteins in integrin αⅡbβ3 bidirectional signal transduction.