Isolation and characterization of insect PC2-like prohormone convertase cDNA

Endoproteolytic processing of large precursor molecules at basic amino acid residues plays an important role in the maturation of many hormones, neuropeptides and other regulatory proteins. Enzymes performing these reactions are designated as prohormone or proprotein convertases and belong to the subtilisin family of serine proteases. The screening of a larval cDNA library of the sheep blowfly Lucilia cuprina resulted in the isolation of two cDNAs encoding a PC2-like prohormone convertase. The predicted 675 amino acid preproprotein (LcuPC2) exhibits its highest identity to invertebrate and vertebrate prohormone convertase 2 homologues, and a noticeably lower identity to the so far known insect furin-like prohormone convertases of Drosophila melanogaster and Aedes aegypti. In Northern blot experiments a signal at 2.5 kb could be detected.