Abstract
Aegerolysins ostreolysin A (OlyA) and pleurotolysin A (PlyA), and pleurotolysin B (PlyB) with the membrane-attack-complex/perforin domain are proteins from the mushroom genus Pleurotus. Upon binding to sphingomyelin/cholesterol-enriched membranes, OlyA and PlyA can recruit PlyB to form multimeric bi-component transmembrane pores. Recently, Pleurotus aegerolysins OlyA, PlyA2 and erylysin A (EryA) were demonstrated to preferentially bind to artificial lipid membranes containing 50 mol% ceramide phosphoethanolamine (CPE), the main sphingolipid in invertebrate cell membranes. In this study, we demonstrate that OlyA6, PlyA2 and EryA bind to insect cells and to artificial lipid membranes with physiologically relevant CPE concentrations. Moreover, these aegerolysins permeabilize these membranes when combined with PlyB. These aegerolysin/PlyB complexes show selective toxicity toward western corn rootworm larvae and adults and Colorado potato beetle larvae. These data strongly suggest that these aegerolysin/PlyB complexes recognize CPE as their receptor molecule in the insect midgut. This mode of binding is different from those described for similar aegerolysin-based bacterial complexes, or other Bacillus thuringiensis Cry toxins, which have protein receptors. Targeting of Pleurotus aegerolysins to CPE and formation of transmembrane pores in concert with PlyB suggest the use of aegerolysin/PlyB complexes as novel biopesticides for the control of western corn rootworm and Colorado potato beetle.
Highlights
Western corn rootworm (WCR; Diabrotica v. virgifera LeConte; Coleoptera, Chrysomelidae) is an important pest on maize in the USA1,2 and Europe[3], and it was reported to cause annual economic losses of over 1 billion dollars in the USA4,5
ostreolysin A (OlyA), OlyA6, and pleurotolysin A (PlyA) were shown to combine with pleurotolysin B (PlyB), a 59-kDa protein partner with a MACPF domain that is produced by P. ostreatus[27,30,38], while erylysin A (EryA) acts in concert with another MACPF-protein, erylysin B (EryB), which shares 96% amino acid sequence identity with PlyB39
We confirmed that while OlyA6 and pleurotolysin A2 (PlyA2) bind to sphingomyelin/cholesterol multilamellar vesicles, EryA was recovered in the supernatant after centrifugation of these vesicles, which suggested no association of EryA with these lipid membranes[33]
Summary
Western corn rootworm (WCR; Diabrotica v. virgifera LeConte; Coleoptera, Chrysomelidae) is an important pest on maize in the USA1,2 and Europe[3], and it was reported to cause annual economic losses of over 1 billion dollars in the USA4,5. The search for alternative biopesticides and approaches is of extreme importance, such as the development of efficient attract-and-kill strategies These efforts very recently resulted in the discovery of novel proteinaceous toxins that are specific for WCR and some other coleoptera. The dissociation constants of OlyA and PlyA2 binding to equimolar CPE/cholesterol and sphingomyelin/cholesterol lipid vesicles were reported to be 10−8 M and >10−5 M, respectively[33,37], which suggests that the interactions of these aegerolysins with CPE-containing membrane systems is at least 1000-fold stronger This discovery led to the use of Pleurotus aegerolysins as useful molecular markers of CPE distribution in insect tissues, and for detection of the bloodstream form of Trypanosoma brucei[33]. The membrane-disrupting potential of these aegerolysin/PlyB complexes has, not been tested on CPE-containing membranes
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
