title: A GPI-anchored alkaline phosphatase is a functional midgut receptor of Cry11Aa toxin in Aedes aegypti larvae.
abstract: A 65 kDa GPI (glycosylphosphatidyl-inositol)-anchored ALP (alkaline phosphatase) was characterized as a functional receptor of the Bacillus thuringiensis subsp. israelensis Cry11Aa toxin in Aedes aegypti midgut cells. Two (a 100 kDa and a 65 kDa) GPI-anchored proteins that bound Cry11Aa toxin were preferentially extracted after treatment of BBMV (brush boder membrane vesicles) from Ae. aegypti midgut epithelia with phospholipase C. The 65 kDa protein was further purified by toxin affinity chromatography. The 65 kDa protein showed ALP activity. The peptide-displaying phages (P1.BBMV and P8.BBMV) that bound to the 65 kDa GPI-ALP (GPI-anchored ALP) and competed with the Cry11Aa toxin to bind to BBMV were isolated by selecting BBMV-binding peptide-phages by biopanning. GPI-ALP was shown to be preferentially distributed in Ae. aegypti in the posterior part of the midgut and in the caeca, by using P1.BBMV binding to fixed midgut tissue sections to determine the location of GPI-ALP. Cry11Aa binds to the same regions of the midgut and competed with P1.BBMV and P8.BBMV to bind to BBMV. The importance of this interaction was demonstrated by the in vivo attenuation of Cry11Aa toxicity in the presence of these phages. Our results shows that GPI-ALP is an important receptor molecule involved in Cry11Aa interaction with midgut cells and toxicity to Ae. aegypti larvae.
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. postal 510-3, Cuernavaca 62250, Morelos, Mexico.
authors.forename: Luisa E
authors.initials: LE
authors.lastname: Fernandez
authors.forename: Karlygash G
authors.initials: KG
authors.lastname: Aimanova
authors.forename: Sarjeet S
authors.initials: SS
authors.lastname: Gill
authors.forename: Alejandra
authors.initials: A
authors.lastname: Bravo
authors.forename: Mario
authors.initials: M
authors.lastname: Soberón
mesh_terms: D000330:Aedes / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D000469:Alkaline Phosphatase / Q000378:metabolism*; D000818:Animals; D001413:Bacillus thuringiensis; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D001427:Bacterial Toxins / Q000378:metabolism*; D018826:CD13 Antigens / Q000378:metabolism; D004731:Endotoxins / Q000378:metabolism*; D041981:Gastrointestinal Tract / Q000166:cytology / Q000201:enzymology; D017261:Glycosylphosphatidylinositols / Q000378:metabolism*; D006460:Hemolysin Proteins; D007814:Larva / Q000201:enzymology / Q000378:metabolism*; D008871:Microvilli / Q000201:enzymology
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D017261:Glycosylphosphatidylinositols; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D000469:Alkaline Phosphatase; D018826:CD13 Antigens