Cadherin-like midgut receptor (Bt-R)

Cadherin-like midgut receptors are large transmembrane glycoproteins located on the brush border membrane of insect midgut epithelial cells (Vadlamani et al., 2012, Journal of Biological Chemistry). They are members of the cadherin superfamily, typically containing multiple extracellular cadherin (EC) repeats that mediate protein-protein interactions and cell-cell adhesion (Gahan et al., 2001, Science). These receptors are the primary targets for Cry toxins derived from the bacterium Bacillus thuringiensis, which are widely used in genetically modified crops and organic farming to control agricultural pests (Pigott and Ellar, 2007, Microbiology and Molecular Biology Reviews). The interaction between the toxin and the receptor is a critical step in the toxin's mode of action, leading to toxin oligomerization, membrane perforation, cell lysis, and the eventual death of the insect (Bravo et al., 2004, Biochimica et Biophysica Acta). Mutations or down-regulation of these receptors are major mechanisms by which insects develop resistance to Bt-based insecticidal strategies, making them a focal point for resistance management research (Soberón et al., 2007, Science). Their high specificity to certain insect orders makes them ideal targets for narrow-spectrum biopesticides that minimize ecological impact on non-target organisms.

Other names

Bt-R1Cadherin-like proteinCry toxin receptorMidgut cadherinCADCadherin-like protein 1

Cry toxins bind to the extracellular cadherin repeats of the receptor, which facilitates proteolytic activation and the formation of a pre-pore oligomer that subsequently inserts into the midgut epithelial membrane to create lethal ion channels (Bravo et al., 2004, Biochimica et Biophysica Acta).