The Q allele variant (GLN121) of membrane glycoprotein PC-1 interacts with the insulin receptor and inhibits insulin signaling more effectively than the common K allele variant (LYS121). - Costanzo,BV.; Trischitta,V.; DiPaola,R.; Spampinato,D.; Pizzuti,A.; Vigneri,R.; Frittitta,L. (Diabetes, 2001)