Alpha-glucosidase 1 (Cqm1) (Cqm1)

The alpha-glucosidase-like GPI-anchored Bin receptor, primarily known as Cqm1 or Cpm1, is a membrane-bound enzyme located in the midgut of mosquito larvae, particularly Culex species (Darboux et al., 2001, J. Biol. Chem.). While its physiological role involves the hydrolysis of maltose into glucose, it serves as the primary target for the binary toxin (Bin) produced by the bacterium Lysinibacillus sphaericus (Ferreira et al., 2010, Insect Biochem. Mol. Biol.). The toxin consists of two subunits, BinA and BinB; BinB specifically recognizes and binds to this GPI-anchored receptor, allowing the toxic BinA subunit to internalize or form pores, ultimately causing midgut epithelial damage and larval death (Opota et al., 2008, Cell. Microbiol.). This interaction is a cornerstone of biological mosquito control programs aimed at reducing the transmission of diseases like West Nile virus and lymphatic filariasis. Resistance to these bio-insecticides often arises from mutations in the gene encoding this receptor, which can lead to the loss of the GPI anchor or altered binding affinity (Silva-Filha et al., 2004, Appl. Environ. Microbiol.). Because the receptor is highly specific to certain mosquito species, the Bin toxin is considered an environmentally friendly alternative to chemical pesticides.

Other names

Cpm1Maltase 1Bin receptorAlpha-glucosidase-like GPI-anchored proteinLysinibacillus sphaericus binary toxin receptor

The BinB component of the Lysinibacillus sphaericus binary toxin binds to the GPI-anchored alpha-glucosidase receptor on the larval midgut epithelium, facilitating the action of the BinA toxin which leads to pore formation, cell lysis, and death of the mosquito larva.