Plasma Growth Arrest-Specific Protein 6 (Gas6) as a Biomarker of Renal Diseases

Abstract

Gas6 (growth arrest-specific 6) is a unique protein belonging to the family of plasma vitamin K-dependent proteins and a ligand for the tyrosine kinase family (Tyro3, Axl, Mer). Gas6 bears a great structural resemblance to the anticoagulant protein S. Interestingly, in spite of the presence of a g-carboxyglutamic acid domain in its structure, Gas6 has not been discored to show any function in the coagulation cascade. Gas6 has been reported to participate in cell proliferation, apoptosis, chemotaxis, leukocyte migration, sequestration, platelet aggregation, vascular homeostasis, and inflammation. In addition, it plays a role in the activation of various kinds of cells, including platelets and endothelial and vascular smooth-muscle cells (VSMC). After it was demonstrated that Gas6 induces proliferation of VSMC and serum-starved NIH 3T3 (mouse embryonic fibroblast cell lines) fibroblasts, mitogenic effects of Gas6 were found in cultured mesangial cells. As a result, it has been reported to take part in various pathophysiological processes, for instance, atherosclerosis, renal diseases, cancer, and thrombosis. The main subject of the present review is the role Gas6 plays in renal diseases.