38th Annual Meeting of the Society for Invertebrate Pathology

Cadherin-like proteins from Bombyx mori, Manduca sexta, Pectinophora gossypiella, and Heliothis virescens have been, directly or indirectly, demonstrated to function as receptors for Cry1A toxins. The objective of this work was to test the putative role of the cadherin protein from Lymantria dispar (LdCad) as receptor for Cry1A toxins.
Two approaches were followed to characterize Cry1A-LdCad interactions. First, truncated LdCad proteins containing regions predicted to be involved in toxin binding were expressed in Escherichia coli. Cry1A toxin binding to these LdCad truncated peptides was tested using ligand blotting, dot blotting and affinity chromatography. In a second approach, full length LdCad was expressed in S2 and High Five insect cell cultures. Expressed LdCad was detected on the surface of the transfected cells by immunocytochemistry. Binding of Cry1A toxins to cells expressing LdCad was tested using dot blotting and fluorescence microscopy. Fluorescence assisted cell sorting (FACS) was used to test cytotoxicity of Cry1A toxins against cells expressing LdCad. In these assays, all Cry1A toxins (but not Cry1Fa) killed cells expressing LdCad, with Cry1Ac being the most active toxin. These results are evidence for a functional Cry1A receptor role for LdCad