Translation of insulin granule proteins are regulated by PDI and PABP

Abstract

Glucose mediated insulin biosynthesis is tightly regulated and shared between insulin granule proteins such as its processing enzymes, prohormone convertases, PC1/3 and PC2. However, the molecular players involved in the co-ordinated translation remain elusive. The trans-acting factors like PABP (Poly A Binding Protein) and PDI (Protein Disulphide Isomerize) binds to a conserved sequence in the 5′UTR of insulin mRNA and regulates its translation. Here, we demonstrate that 5′UTR of PC1/3 and PC2 also associate with PDI and PABP. We show that a’ and RRM 3–4 domains of PDI and PABP respectively, are necessary for RNA binding activity to the 5′UTRs of insulin and its processing enzymes.