The Cry1Ie1 delta-endotoxin is an insecticidal protein produced by Bacillus thuringiensis. The protein has insecticidal activity against lepidopteran pests, but not coleopteran insects. Once trypsin activated, the N-terminus of the protein can bind receptors on the brush border membrane vesicles and peritrophic matrix, which is then followed by oligomerization, membrane insertion, and pore-formation. The newly formed channel causes an influx of water, cell swelling and eventual lysis, leading to the destruction of the larval midgut epithelium and death of susceptible larvae. Research indicates that this protein interacts with receptor proteins are different from those that crystal protein Cry1Ab interacts with.