Proteomic identification of Bacillus thuringiensis subsp. israelensis toxin Cry4Ba binding proteins in midgut membranes from Aedes (Stegomyia) aegypti Linnaeus (Diptera, Culicidae) larvae.
Novel Bacillus thuringiensis subsp. israelensis (Bti) Cry4Ba toxin-binding proteins have been identified in gut brush border membranes of the Aedes (Stegomyia) aegypti mosquito larvae by combining 2-dimensional gel electrophoresis (2DE) and ligand blotting followed by protein identification using mass spectrometry and database searching. Three alkaline phosphatase isoforms and aminopeptidase were identified. Other Cry4Ba binding proteins identified include the putative lipid raft proteins flotillin and prohibitin, V-ATPase B subunit and actin. These identified proteins might play important roles in mediating the toxicity of Cry4Ba due to their location in the gut brush border membrane. Cadherin-type protein was not identified, although previously, we identified a midgut cadherin AgCad1 as a putative Cry4Ba receptor in Anopheles gambiae mosquito larvae [Hua, G., Zhang, R., Abdullah, M.A., Adang, M.J., 2008. Anopheles gambiae cadherin AgCad1 binds the Cry4Ba toxin of Bacillus thuringiensis israelensis and a fragment of AgCad1 synergizes toxicity. Biochemistry 47, 5101-5110]. Other identified proteins in this study that might have lesser roles include mitochondrial proteins such as ATP synthase subunits, mitochondrial processing peptidase and porin; which are likely contaminants from mitochondria and are not brush border membrane components. Trypsin-like serine protease was also identified as a protein that binds Cry4Ba. Identification of these toxin-binding proteins will lead to a better understanding of the mode of action of this toxin in mosquito.
Bayyareddy
Krishnareddy
K
Department of Entomology, University of Georgia, Athens, GA 30602-2603, USA.
Andacht
Tracy M
TM
Abdullah
Mohd Amir
MA
Adang
Michael J
MJ
D000330:Aedes / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D002462:Cell Membrane / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D004064:Digestive System / Q000737:chemistry / Q000378:metabolism; D015180:Electrophoresis, Gel, Two-Dimensional; D004731:Endotoxins / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000378:metabolism*; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D007814:Larva / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D008970:Molecular Weight; D011485:Protein Binding; D040901:Proteomics
D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis