Insecticidal protein Mpp75Aa1.1 is a member of the ETX_MTX family of beta-pore forming proteins with insecticidal activity against Coleoptera. The protein interacts with putative membrane-associated binding partners on the midgut apical microvilli. The protein has a similar mode of action to Cry proteins (from Bacillus thuringiensis), in which the protein is ingested and proteolytically activated, before binding a receptor and oligomerizing in the membrane to form a pore, resulting in cell death. The cellular damage results in death of the insect. The protein differs from Bt toxins as it forms beta-barrel pores instead of alpha-helical transmembrane pores. The protein consists: Domain I, receptor binding region; and Domain II and III, involved in pore formation.