You are here: Home
/ Publication Information
Title: Bacillus thuringiensis pore-forming toxins trigger massive shedding of GPI-anchored aminopeptidase N from gypsy moth midgut epithelial cells
Author: Valaitis, Algimantas P.;
Source: Insect Biochemistry and Molecular Biology. 38: 611-618.
Publication Series: Scientific Journal (JRNL)
Description: The insecticidal Cry proteins produced by Bacillus thuringiensis strains are pore-forming toxins (PFTs) that bind to the midgut brush border membrane and cause extensive damage to the midgut epithelial cells of susceptible insect larvae. Force-feeding B. thuringiensis PFTs to Lymantria dispar larvae elicited rapid and massive shedding of a glycosylphosphatidylinositol (GPI)-anchored aminopeptidase N (APN) from midgut epithelial cells into the luminal fluid, and depletion of the membrane-anchored enzyme on the midgut epithelial cells. The amount of APN released into the luminal fluid of intoxicated larvae was dose- and time-dependent, and directly related to insecticidal potency of the PFTs. The induction of toxin-induced shedding of APN was inhibited by cyclic AMP and MAPK kinase (MEK) inhibitors PD98059 and U0126, indicating that signal transduction in the MEK/ERK pathway is involved in the regulation of the shedding process. APN released from epithelial cells appears to be generated by the action of a phosphatidylinositol-specific phospholipase C (PI-PLC) cleavage of the GPI anchor based upon detection of a cross-reacting determinant (CRD) on the protein shed into the luminal fluid. Alkaline phosphatase was also released from the gut epithelial cells, supporting the conclusion that other GPI-anchored proteins are released as a consequence of the activation PI-PLC. These observations are the basis of a novel and highly sensitive tool for evaluating the insecticidal activity of new Cry proteins obtained though discovery or protein engineering.
Keywords: Bacillus thuringiensis, pore-forming toxins, aminopeptidase N, shedding, signal transduction
- We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
- This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.
- This publication may be available in hard copy. Check the Northern Research Station web site to request a printed copy of this publication.
- Our on-line publications are scanned and captured using Adobe Acrobat. During the capture process some typographical errors may occur. Please contact Sharon Hobrla, firstname.lastname@example.org if you notice any errors which make this publication unusable.
XML: View XML
Valaitis, Algimantas P. 2008. Bacillus thuringiensis pore-forming toxins trigger massive shedding of GPI-anchored aminopeptidase N from gypsy moth midgut epithelial cells. Insect Biochemistry and Molecular Biology. 38: 611-618.
Get the latest version of the Adobe Acrobat reader or Acrobat Reader for Windows with Search and Accessibility