Gas6 is a novel growth factor for kidney mesangial cells, and is posttranslationally activated by C-carboxylation in the presence of vitamin K. In diabetic nephropathy, streptozotocin-treated Gas6 knockout mice exhibit less pronounced glomerular hypertrophy and glycoxidized low-density lipoprotein increase in mouse mesangial cells [7], [9]. This evidence concerns the gene GAS6 and diabetic kidney disease.