Fungal aegerolysin-like proteins: distribution, activities, and applications

Abstract

The aegerolysin protein family (from aegerolysin of the mushroom Agrocybe aegerita) comprises proteins of ∼15-20 kDa from various eukaryotic and bacterial taxa. Aegerolysins are inconsistently distributed among fungal species, and variable numbers of homologs have been reported for species within the same genus. As such noncore proteins, without a member of a protein family in each of the sequenced fungi, they can give insight into different species-specific processes. Some aegerolysins have been reported to be hemolytically active against mammalian erythrocytes. However, some function as bi-component proteins that have membrane activity in concert with another protein that contains a membrane attack complex/perforin domain. The function of most of aegerolysins is unknown, although some have been suggested to have a role in development of the organism. Potential biotechnological applications of aegerolysins are already evident, despite the limited scientific knowledge available at present. Some mushroom aegerolysins, for example, can be used as markers to detect and label specific membrane lipids. Others can be used as biomarkers of fungal exposure, where their genes can serve as targets for detection of fungi and their progression during infectious diseases. Antibodies against aegerolysins can also be raised as immuno-diagnostic tools. Aegerolysins have been shown to serve as a species determination tool for fungal phytopathogen isolates in terms of some closely related species, where commonly used internal transcribed spacer barcoding has failed. Moreover, strong promoters that regulate aegerolysin genes can promote secretion of heterologous proteins from fungi and have been successfully applied in simultaneous multi-gene expression techniques.

An Alcaligenes strain emulates Bacillus thuringiensis producing a binary protein that kills corn rootworm through a mechanism similar to Cry34Ab1/Cry35Ab1

“…We were unable to detect any relationship between the sequences of the two molecules or between AfIP-1B and any other sequence in the Protein Data Bank 31 using sequence or profile alignment methods 18, 32 . Interestingly, some of the members of the aegerolysin family, to which AfIP-1A appears to belong, have binary interacting partners that belong to the Membrane Attack Complex Perforin (MACPF) family 33 . However, we were unable to identify any significant relationship between AfIP-1B and the MACPF family using current sequence/profile alignment methods.…”

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

“…The aegerolysin protein family (PF06355; InterPro IPR009413) is currently composed of more than 350 low-molecular-weight (15-20 kDa), acidic, β-structured proteins that have been found in several eukaryotic and bacterial taxa, and are particularly abundant in fungi (Berne et al, 2009;Novak et al, 2015;Butala et al, 2017). The exact biological role of these proteins in fungi is still not clear.…”

“…The fungal genus Aspergillus is of critical importance to humankind because these species are a source of many industrial applications, while also being important pathogens of humans, animals and crops, potent carcinogenic contaminants of food, and an important genetic model (de Vries et al, 2017). To date, over 30 predicted aegerolysin proteins have been found in 18 Aspergillus species, but only a few have been described so far (Novak et al, 2015). The first ever reported aegerolysin protein, Asphemolysin (AspHS), was isolated from the filamentous fungus Aspergillus fumigatus, the main causative agent of invasive aspergillosis in immunocompromised patients (Sakaguchi et al, 1975).…”

Functional characterization of the AGL1 aegerolysin in the mycoparasitic fungus Trichoderma atroviride reveals a role in conidiation and antagonism

“…The aim of this study was to characterize the biological function of an aegerolysin protein in the fungus Trichoderma atroviride, used for biological control of plant pathogenic fungi in agriculture, with emphasis on its role in asexual development and interactions with other fungi. Aegerolysin (Pfam 06355, InterPro IPR009413) is a family of lipid-binding proteins that are found in both prokaryotes and eukaryotes (Novak et al 2015;Butala et al 2017). Aegerolysin family proteins are typically small (15-20 kDa) with low isoelectric point, a predicted β-structure and are shown to be active in a broad pH range from 3.5 to 10.5 (Novak et al 2015;Butala et al 2017).…”

“…Aegerolysin (Pfam 06355, InterPro IPR009413) is a family of lipid-binding proteins that are found in both prokaryotes and eukaryotes (Novak et al 2015;Butala et al 2017). Aegerolysin family proteins are typically small (15-20 kDa) with low isoelectric point, a predicted β-structure and are shown to be active in a broad pH range from 3.5 to 10.5 (Novak et al 2015;Butala et al 2017). In fungi, aegerolysins are reported from many species with varying lifestyles and ecological niches; however, functional characterization is only reported from a few species.…”