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.
KEYWORDS: Insulin granule proteins, PABP, PDI, Prohormone convertases