Maianu et al. (2001) examined the subcellular localization of both GLUT4 and IRAP in adipocytes isolated from healthy controls and type 2 diabetics and found that despite no detectable difference in IRAP protein expression between groups, IRAP and GLUT4 trafficking in diabetic patients appeared to be altered with redistribution to high-density microsomes and plasma membrane fractions in basal cells and impaired translocation following insulin stimulation. This results in impaired insulin action and a decrease in insulin-responsive vesicular trafficking (Maianu et al., 2001). This evidence concerns the gene LNPEP and type 2 diabetes mellitus.