Aedes aegypti alkaline phosphatase ALP1 is a functional receptor of Bacillus thuringiensis Cry4Ba and Cry11Aa toxins

• Published in: Insect biochemistry and molecular biology Vol. 42; no. 9; pp. 683 - 689
• Main Authors: Jiménez, Alan I, Reyes, Esmeralda Z, Cancino-Rodezno, Angeles, Bedoya-Pérez, Leidy P, Caballero-Flores, Gustavo G, Muriel-Millan, Luis F, Likitvivatanavong, Supaporn, Gill, Sarjeet S, Bravo, Alejandra, Soberón, Mario
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.09.2012
• Subjects: Aedes - enzymology; Aedes - genetics; Aedes aegypti; Alkaline phosphatase; Alkaline Phosphatase - genetics; Alkaline Phosphatase - metabolism; Animals; Bacillus thuringiensis; Bacterial Proteins - metabolism; Cry toxins; digestive system; Endotoxins - metabolism; Gene Silencing; Hemolysin Proteins - metabolism; Insect Proteins - genetics; Insect Proteins - metabolism; Insecticides - metabolism; Larva; larvae; mutants; protein synthesis; proteins; quantitative polymerase chain reaction; Receptors; RNA interference; RNA silencing; toxicity; toxins; Western blotting; Alkaline phosphatase; Cry toxins; Receptors; Aedes aegypti; RNA silencing; Bacillus thuringiensis
• ISSN: 0965-1748; 1879-0240
• DOI: 10.1016/j.ibmb.2012.06.001

Bacillus thuringiensis subs. israelensis produces at least three Cry toxins (Cry4Aa, Cry4Ba, and Cry11Aa) that are active against Aedes aegypti larvae. Previous work characterized a GPI-anchored alkaline phosphatase (ALP1) as a Cry11Aa binding molecule from the gut of A. aegypti larvae. We show here that Cry4Ba binds ALP1, and that the binding and toxicity of Cry4Ba mutants located in loop 2 of domain II is correlated. Also, we analyzed the contribution of ALP1 toward the toxicity of Cry4Ba and Cry11Aa toxins by silencing the expression of this protein though RNAi. Efficient silencing of ALP1 was demonstrated by real-time quantitative PCR (qPCR) and Western blot. ALP1 silenced larvae showed tolerance to both Cry4Ba and Cry11Aa although the silenced larvae were more tolerant to Cry11Aa in comparison to Cry4Ba. Our results demonstrate that ALP1 is a functional receptor that plays an important role in the toxicity of the Cry4Ba and Cry11Aa proteins.