ShK-Domain-Containing Protein from a Parasitic Nematode Modulates Drosophila melanogaster Immunity

Abstract

A key component to understanding host–parasite interactions is the molecular crosstalk between host and parasite. Excreted/secreted products (ESPs) released by parasitic nematodes play an important role in parasitism. They can directly damage host tissue and modulate host defense. Steinernema carpocapsae, a well-studied parasite of insects releases approximately 500 venom proteins as part of the infection process. Though the identity of these proteins is known, few have been studied in detail. One protein family present in the ESPs released by these nematodes is the ShK family. We studied the most abundant ShK-domain-containing protein in S. carpocapsae ESPs, Sc-ShK-1, to investigate its effects in a fruit fly model. We found that Sc-ShK-1 is toxic under high stress conditions and negatively affects the health of fruit flies. We have shown that Sc-ShK-1 contributes to host immunomodulation in bacterial co-infections resulting in increased mortality and microbial growth. This study provides an insight on ShK-domain-containing proteins from nematodes and suggests these proteins may play an important role in host–parasite interactions.

Functional Characterization of ShK Domain-Containing Protein in the Plant-Parasitic Nematode Bursaphelenchus xylophilus

“…The ShKT domain-containing proteins in the phylum Nematoda are present in the free-living Caenorhabditis elegans, with ca. 66 secreted ShKT proteins containing multiple copies of the ShK toxin domain [20], in the entomopathogenic nematode Steinernema carpocapsae [21,22], in the plant-parasitic nematodes Radopholus similis [23], Pratylenchus penetrans [24], Meloidogyne javanica [25], Heterodera schachtii [26], and in the animal-parasitic species Toxocara canis [15] and Trichostrongylus colubriformis [27]. In the parasitic and venomous species, the peptides with the ShKT domain have been shown to function as K + channel blockers [15,[28][29][30].…”

“…In the phylum Nematoda, ShK toxins present in the animal-parasitic nematodes Ancyclostoma caninum (AcK1) and Brugia malayi (BmK1) are used as a selective inhibitor of K v channels to treat autoimmune disease [30]. In the entomopathogenic nematode S. carpocapsae, the presence of ShK peptides has been associated with the modulation of the host immunity during infection and their potential to be an insecticidal peptide [21,22]. In the plant-parasitic nematode M. javanica, ShK peptides (MjShKT) are highly secreted into the host cells and inhibit programmed cell death, allowing the nematode to invade and reproduce inside the host tissues [25].…”

Functional Characterization of ShK Domain-Containing Protein in the Plant-Parasitic Nematode <em>Bursaphelenchus xylophilus</em>

“…The ShKT-domain containing proteins on the Phylum Nematoda is present in the free living Caenorhabditis elegans, with ca. 66 secreted ShKT proteins containing multiple copies of the ShK toxin domain [20], in the entomopathogenic nematode Steinernema carpocapsae [21,22], in the plant-parasitic nematodes…”

“…carpocapsae, the presence of ShK peptides has been associated with the modulation of the host immunity during infection and their potential to be an insecticidal peptide [21,22]. In the plantparasitic nematode M. javanica, ShK peptides (MjShKT) are highly secreted into the host cells, inhibit programmed cell death, allowing the nematode to invade and reproduce inside the host tissues [25].…”