Journal News

JBC: Serpins in wasp venom block host immune response

Mariana Figuera-Losada
By Mariana Figuera-Losada
May 1, 2017

In May 1860, a bewildered Charles Darwin wrote a letter to the botanist Asa Gray to say, “I cannot persuade myself that a beneficent and omnipotent God would have designedly created the Ichneumonidae with the express intention of their feeding within the living bodies of caterpillars.”

Darwin was referring to parasitoid wasps. This group of insects is estimated to have up to 600,000 species, according to Gong-yin Ye at the Institute of Insect Science in Zhejiang University in China. The number makes parasitoid wasps the most abundant and diverse group of insects on Earth. The study of some of the molecular mechanisms of the relationship between one of these parasitoid wasps and its host, a butterfly, is the subject of Ye’s recent paper in the Journal of Biological Chemistry. Ye and colleagues described the discovery of a splicing isoform of a serine protease inhibitor found in the venom of the wasp that can inhibit its host’s immunity.

Endoparasitoid wasps lay their eggs inside the body of their hosts, while ectoparasitoid wasps do so on the body surface of their hosts. Eggs hatch and feed on the hosts, killing them.

P. puparum lays its eggs in a butterfly pupa
Courtesy of Gongyin Ye
P. puparum lays its eggs in a butterfly pupa.

Most of the known pest insects that attack crops are preyed upon by parasitoid wasps, which is why they regularly have been deployed to protect crops. Pteromalus puparum is a gregarious endoparasitoid wasp that attacks the pupal stage of several butterfly species, including Pieris rapae, the cabbage white butterfly, which can be a problem in commercial farming of cabbage, broccoli and cauliflower.

Ye explains that to increase the chance of survival of its offspring, these wasps inject venom along with their eggs to suppress host immune defenses. Melanization, one of the processes of host immunity, is a conserved and highly regulated process. It consists of a series of serine protease activation reactions that culminate in the production of prophenoloxidase-activating proteases, which further catalyze the conversion of prophenoloxidase into phenoloxidase. In turn, phenoloxidase oxidizes tyrosine and o-diphenols to quinones, which polymerize to form melanin that can cover the surface of pest invaders and keep them from spreading or hatching and completing development.

In a previous study, using a combination of transcriptomic and proteomic approaches, Ye and colleagues found that the venom of P. puparum contains at least 70 different putative proteins that include proteases, inhibitors, and recognition and binding proteins.

In the JBC paper, Ye and colleagues show that the P. puparum venom blocks melanization by both the host pupae and larvae. By using a number of protein fractionation steps followed by sequence analyses of the isolated proteins, the authors identified a serine protease inhibitor or serpin. They named this inhibitor PpS1V.

Serpins are a family of inhibitors that react with their target protease via a reactive center loop to form an inactive complex. Ye and colleagues found that PpS1V is one of the 16 predicted putative splicing isoforms that differ in their eighth and last exon, which contains the reactive center loop. They found that PpS1V binds and inhibits the activity of a previously unknown host protein, which they called P. rapae prophenoloxidase-activating proteinase 1, which is possibly involved in melanization by the host.

Ye thinks that uncovering the mechanisms by which parasitoid wasps inhibit host immunity will yield potential candidates for novel insecticides. Considering the parasitoid wasps’ diversity, these animals are an untapped source of bioactive compounds for pest control and drug discovery.

Enjoy reading ASBMB Today?

Become a member to receive the print edition four times a year and the digital edition monthly.

Learn more
Mariana Figuera-Losada
Mariana Figuera-Losada

Mariana Figuera-Losada is a research consultant at Montefiore Medical Center.

Get the latest from ASBMB Today

Enter your email address, and we’ll send you a weekly email with recent articles, interviews and more.

Latest in Science

Science highlights or most popular articles

ApoA1 reduce atherosclerotic plaques via cell death pathway
Journal News

ApoA1 reduce atherosclerotic plaques via cell death pathway

Oct. 1, 2025

Researchers show that ApoA1, a key HDL protein, helps reduce plaque and necrotic core formation in atherosclerosis by modulating Bim-driven macrophage death. The findings reveal new insights into how ApoA1 protects against heart disease.

Omega-3 lowers inflammation, blood pressure in obese adults
Journal News

Omega-3 lowers inflammation, blood pressure in obese adults

Oct. 1, 2025

A randomized study shows omega-3 supplements reduce proinflammatory chemokines and lower blood pressure in obese adults, furthering the understanding of how to modulate cardiovascular disease risk.

AI unlocks the hidden grammar of gene regulation
Feature

AI unlocks the hidden grammar of gene regulation

Sept. 30, 2025

Using fruit flies and artificial intelligence, Julia Zeitlinger’s lab is decoding genome patterns — revealing how transcription factors and nucleosomes control gene expression, pushing biology toward faster, more precise discoveries.

Zebrafish model links low omega-3s to eye abnormalities
Journal News

Zebrafish model links low omega-3s to eye abnormalities

Sept. 24, 2025

Researchers at the University of Colorado Anschutz developed a zebrafish model to show that low maternal docosahexaenoic acid can disrupt embryo eye development and immune gene expression, offering a tool to study nutrition in neurodevelopment.

Top reviewers at ASBMB journals
Observance

Top reviewers at ASBMB journals

Sept. 19, 2025

Editors recognize the heavy-lifters and rising stars during Peer Review Week.

Teaching AI to listen
Essay

Teaching AI to listen

Sept. 18, 2025

A computational medicine graduate student reflects on building natural language processing tools that extract meaning from messy clinical notes — transforming how we identify genetic risk while redefining what it means to listen in science.