title: AgCad2 cadherin in Anopheles gambiae larvae is a putative receptor of Cry11Ba toxin of Bacillus thuringiensis subsp. jegathesan.
abstract: In an effort to study the mode of action of Cry11Ba, we identified toxin binding proteins in Anopheles gambiae larval midgut and investigated their receptor roles. Previously, an aminopeptidase (AgAPN2) and an alkaline phosphatase (AgALP1) were identified as receptors for Cry11Ba toxin in A. gambiae. However, an A. gambiae cadherin (AgCad1) that bound Cry11Ba with low affinity (K(d) = 766 nM) did not support a receptor role of AgCad1 for Cry11Ba. Here, we studied a second A. gambiae cadherin (AgCad2) that shares 14% identity to AgCad1. Immunohistochemical study showed that the protein is localized on A. gambiae larval midgut apical membranes. Its cDNA was cloned and the protein was analyzed as a transmembrane protein containing 14 cadherin repeats. An Escherichia coli expressed CR14MPED fragment of AgCad2 bound Cry11Ba with high affinity (K(d) = 11.8 nM), blocked Cry11Ba binding to A. gambiae brush border vesicles and reduced Cry11Ba toxicity in bioassays. Its binding to Cry11Ba could be completely competed off by AgCad1, but only partially competed by AgALP1. The results are evidence that AgCad2 may function as a receptor for Cry11Ba in A. gambiae larvae.
authors.affiliation: Department of Entomology, University of Georgia, Athens, GA 30602-2603, USA.
authors.forename: Gang
authors.initials: G
authors.lastname: Hua
authors.forename: Qi
authors.initials: Q
authors.lastname: Zhang
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: Amir M
authors.initials: AM
authors.lastname: Abdullah
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Linser
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Adang
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000852:Anopheles / Q000737:chemistry / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D001413:Bacillus thuringiensis / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015820:Cadherins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004731:Endotoxins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007413:Intestinal Mucosa / Q000378:metabolism; D007422:Intestines / Q000737:chemistry; D007700:Kinetics; D007814:Larva / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D008969:Molecular Sequence Data; D011485:Protein Binding; D021381:Protein Transport
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D015820:Cadherins; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis