Still further, an IR-interacting membrane glycoprotein, PC-1 (also called ENPP-1), has been implicated in insulin resistance and type 2 diabetes [17]–[21]; PC-1 seems to impair IR tyrosine kinase activity through a direct interaction of PC-1 with IR that does not affect insulin binding [22]–[23]. This evidence concerns the gene ENPP1 and type 2 diabetes mellitus.