Entomotoxic and nematotoxic lectins and protease inhibitors from fungal fruiting bodies

Abstract

Fruiting bodies or sporocarps of dikaryotic (ascomycetous and basidiomycetous) fungi, commonly referred to as mushrooms, are often rich in entomotoxic and nematotoxic proteins that include lectins and protease inhibitors. These protein toxins are thought to act as effectors of an innate defense system of mushrooms against animal predators including fungivorous insects and nematodes. In this review, we summarize current knowledge about the structures, target molecules, and regulation of the biosynthesis of the best characterized representatives of these fungal defense proteins, including galectins, beta-trefoil-type lectins, actinoporin-type lectins, beta-propeller-type lectins and beta-trefoil-type chimerolectins, as well as mycospin and mycocypin families of protease inhibitors. We also present an overview of the phylogenetic distribution of these proteins among a selection of fungal genomes and draw some conclusions about their evolution and physiological function. Finally, we present an outlook for future research directions in this field and their potential applications in medicine and crop protection.

Functional studies of aegerolysin and MACPF‐like proteins in Aspergillus niger

“…mites and insect larvae). Many of the observed characteristics for aegerolysin proteins in A. niger resemble those described for secondary metabolites and lectins in fungi who act as defence molecules in organisms that produce them (Calvo et al ., ; Mylonakis et al ., ; Künzler, ; Sabotič et al ., ). Therefore, this leads us to believe that the main role(s) of aegerolysins in A. niger are linked to the defence/protection of the fungus during the sensitive period of its development, rather than to growth and development of the fungus.…”

Comparative Study of Lectin Domains in Model Species: New Insights into Evolutionary Dynamics

“…Although lectins from plants and other species have been an important topic of research for years, most studies dealt with the identification and expansion of a particular lectin family in one species, or specifically focused on one type of lectin motif and its distribution in the plant kingdom [27,28,29,30,31,32,33,34,35,36]. To date, there have only been a few publications that report on the distribution of multiple lectin motifs across plant species.…”

Fungal lectin MpL enables entry of protein drugs into cancer cells and their subcellular targeting

“…MpL differs from other fungal entomotoxic and nematotoxic β-galactoside-binding lectins, which were shown to have negative effects on the proliferation of mammalian cell lines [6]. Treatment of human cell lines showed that, even at fairly high concentrations, MpL has no effect on cell viability/proliferation, but is rapidly internalized and accumulated within certain subcellular compartments.…”

“…The first discovered and the most extensively investigated are lectins from plants, however, in recent years fungal lectins have been gaining more attention [4,5]. Fungal lectins differ from their counterparts from other species in their unique structures and binding specificities [6]. They have shown to be very stable proteins, resistant to changes in pH and temperature as well as to proteolytic digestion, which strengthens their potential for application in biotechnology and medicine.…”

“…MpL is structurally similar to the B subunit of ricin, a lectin from the castor bean Ricinus communis, a canonical member of the β-trefoil-type lectins [8,9]. Fungal β-trefoil type lectins exhibit remarkable diversity in their binding partners, which include carbohydrates and proteins [6,10,11]. MpL is active as a dimer and possesses a strong carbohydrate binding domain specific for terminal N-acetyllactosamine and other β-galactosides on α-repeat and a putative carbohydrate binding domain with unknown specificity on γ-repeat [7].…”