An ADAM metalloprotease is a Cry3Aa Bacillus thuringiensis toxin receptor

Ochoa-Campuzano, Camila; Real, M. Dolores; Martínez‐Ramírez, Amparo C.; Bravo, Alejandra; Rausell, Carolina

doi:10.1016/j.bbrc.2007.07.197

Cited by 55 publications

(50 citation statements)

References 25 publications

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“…Saturable binding to specific receptors has been shown amply with Cry1 proteins (reviewed in reference 37) and more limitedly with the coleopteran-active Cry3A (6,30,34,41) and the dipteran-specific Cry4 and Cry11 class proteins (1,11,31,35). In contrast, an early study of the mode of action of Cry2Aa proposed a unique mode of action for this protein in that binding was nonsaturable (13).…”

Section: Homologous-competition Assays Withmentioning

confidence: 99%

Specific Binding of Bacillus thuringiensis Cry2A Insecticidal Proteins to a Common Site in the Midgut of Helicoverpa Species

Hernández‐Rodríguez

Vliet

Bautsoens

et al. 2008

Appl Environ Microbiol

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For a long time, it has been assumed that the mode of action of Cry2A toxins was unique and different from that of other three-domain Cry toxins due to their apparent nonspecific and unsaturable binding to an unlimited number of receptors. However, based on the homology of the tertiary structure among three-domain Cry toxins, similar modes of action for all of them are expected. To confirm this hypothesis, binding assays were carried out with 125 I-labeled Cry2Ab. Saturation assays showed that Cry2Ab binds in a specific and saturable manner to brush border membrane vesicles (BBMVs) of Helicoverpa armigera. Homologous-competition assays with125 I-Cry2Ab demonstrated that this toxin binds with high affinity to binding sites in H. armigera and Helicoverpa zea midgut. Heterologous-competition assays showed a common binding site for three toxins belonging to the Cry2A family (Cry2Aa, Cry2Ab, and Cry2Ae), which is not shared by Cry1Ac. Estimation of K d (dissociation constant) values revealed that Cry2Ab had around 35-fold less affinity than Cry1Ac for BBMV binding sites in both insect species. Only minor differences were found regarding R t (concentration of binding sites) values. This study questions previous interpretations from other authors performing binding assays with Cry2A toxins and establishes the basis for the mode of action of Cry2A toxins.

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Section: Homologous-competition Assays Withmentioning

confidence: 99%

Specific Binding of Bacillus thuringiensis Cry2A Insecticidal Proteins to a Common Site in the Midgut of Helicoverpa Species

Hernández‐Rodríguez

Vliet

Bautsoens

et al. 2008

Appl Environ Microbiol

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“…Activated Cry3A toxin binds to brush border membrane vesicles with a K d (dissociation constant) of ϳ37 nM (19) and recognizes a 144-kDa binding protein in brush border membrane vesicles prepared from the yellow mealworm Tenebrio molitor (Coleoptera: Tenebrionidae) (2). Recently, Ochoa-Campuzano et al (20) identified an ADAM metalloprotease as a receptor for Cry3Aa toxin in CPB larvae.…”

mentioning

confidence: 99%

Enhancement ofBacillus thuringiensisCry3Aa and Cry3Bb Toxicities to Coleopteran Larvae by a Toxin-Binding Fragment of an Insect Cadherin

Park¹,

Abdullah

Taylor

et al. 2009

Appl Environ Microbiol

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The Cry3Aa and Cry3Bb insecticidal proteins of Bacillus thuringiensis are used in biopesticides and transgenic crops to control larvae of leaf-feeding beetles and rootworms. Cadherins localized in the midgut epithelium are identified as receptors for Cry toxins in lepidopteran and dipteran larvae. Previously, we discovered that a peptide of a toxin-binding cadherin expressed in Escherichia coli functions as a synergist for Cry1A toxicity against lepidopteran larvae and Cry4 toxicity against dipteran larvae. Here we report that the fragment containing the three most C-terminal cadherin repeats (CR) from the cadherin of the western corn rootworm binds toxin and enhances Cry3 toxicity to larvae of naturally susceptible species. The cadherin fragment (CR8 to CR10 [CR8-10]) of western corn rootworm Diabrotica virgifera virgifera was expressed in E. coli as an inclusion body. By an enzyme-linked immunosorbent microplate assay, we demonstrated that the CR8-10 peptide binds ␣-chymotrypsin-treated Cry3Aa and Cry3Bb toxins at high affinity (11.8 nM and 1.4 nM, respectively). Coleopteran larvae ingesting CR8-10 inclusions had increased susceptibility to Cry3Aa or Cry3Bb toxin. The Cry3 toxin-enhancing effect of CR8-10 was demonstrated for Colorado potato beetle Leptinotarsa decemlineata, southern corn rootworm Diabrotica undecimpunctata howardi, and western corn rootworm. The extent of Cry3 toxin enhancement, which ranged from 3-to 13-fold, may have practical applications for insect control. Cry3-containing biopesticides that include a cadherin fragment could be more efficacious. And Bt corn (i.e., corn treated with B. thuringiensis to make it resistant to pests) coexpressing Cry3Bb and CR8-10 could increase the functional dose level of the insect toxic activity, reducing the overall resistance risk.

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“…In mosquito larvae, homologous APN, CAD-like, and alkaline phosphatase proteins have been described as Cry11 and Cry4 receptor proteins (6), and in Coleoptera a cadherin-like protein has been demonstrated to act as a Cry3Aa receptor (7). In coleopteran insects, other molecules, such as an ADAM-like metalloprotease (8) and alkaline phosphatase (9), have been proposed as putative Cry receptors. The best characterized Cry receptors, APN and CAD-like proteins, have been unequivocally involved in a Bt mode of action by gene silencing, resulting in a reduced sensitivity to toxin (10,11).…”

mentioning

confidence: 99%

Sodium Solute Symporter and Cadherin Proteins Act as Bacillus thuringiensis Cry3Ba Toxin Functional Receptors in Tribolium castaneum

Contreras

Schoppmeier

Real

et al. 2013

Journal of Biological Chemistry

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Background: Interaction with insect midgut receptors is required for Bacillus thuringienesis (Bt) toxicity. Results: RNAi knockdown of E-cadherin and sodium solute symporter (SSS) genes dramatically decreases Tribolium castaneum (Tc) larval susceptibility to Cry3Ba. A SSS fragment enhances Cry3Ba toxicity. Conclusion: E-cadherin and SSS but not aminopeptidase N are Cry3Ba receptors in Tc. Significance: For the first time, SSS was demonstrated as a Bt functional receptor.

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An ADAM metalloprotease is a Cry3Aa Bacillus thuringiensis toxin receptor

Cited by 55 publications

References 25 publications

Specific Binding of Bacillus thuringiensis Cry2A Insecticidal Proteins to a Common Site in the Midgut of Helicoverpa Species

Specific Binding of Bacillus thuringiensis Cry2A Insecticidal Proteins to a Common Site in the Midgut of Helicoverpa Species

Enhancement ofBacillus thuringiensisCry3Aa and Cry3Bb Toxicities to Coleopteran Larvae by a Toxin-Binding Fragment of an Insect Cadherin

Sodium Solute Symporter and Cadherin Proteins Act as Bacillus thuringiensis Cry3Ba Toxin Functional Receptors in Tribolium castaneum

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