Biochemical characterization and comparison of aspartylglucosaminidases secreted in venom of the parasitoid wasps Asobara tabida and Leptopilina heterotoma

• Published in: PloS one 2017-07, Vol.12 (7), p.e0181940-e0181940
• Main Authors: Coulette, Quentin, Lemauf, Séverine, Colinet, Dominique, Prévost, Geneviève, Anselme, Caroline, Poirié, Marylène, Gatti, Jean-Luc
• Format: Article
• Language: English
• Subjects: Abundance; Amino Acid Sequence; Animals; Arthropods; Asobara tabida; Asparaginase; Aspartylglucosylaminase - chemistry; Aspartylglucosylaminase - metabolism; Autocatalysis; Biochemistry; Biology and Life Sciences; Brain cancer; Comparative analysis; Degradation; Drosophila; Drosophila melanogaster; Drosophila melanogaster - parasitology; Enzymes; Glycoproteins; Insects; Larvae; Leptopelinae; Leptopilina heterotoma; Leukemia; Life Sciences; Mammals; Medicine and Health Sciences; Models, Molecular; Parasitoids; Phylogeny; Physiological aspects; Physiology; Proteins; Proteomics; Research and Analysis Methods; Residues; Secretion; Sequence Alignment; Venom; Venoms; Verne, Jules (1828-1905); Virulence; Virulence factors; Wasp Venoms - chemistry; Wasp Venoms - metabolism; Wasps; Wasps - chemistry; Wasps - enzymology; Wasps - metabolism
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0181940

Aspartylglucosaminidase (AGA) is a low-abundance intracellular enzyme that plays a key role in the last stage of glycoproteins degradation, and whose deficiency leads to human aspartylglucosaminuria, a lysosomal storage disease. Surprisingly, high amounts of AGA-like proteins are secreted in the venom of two phylogenetically distant hymenopteran parasitoid wasp species, Asobara tabida (Braconidae) and Leptopilina heterotoma (Cynipidae). These venom AGAs have a similar domain organization as mammalian AGAs. They share with them key residues for autocatalysis and activity, and the mature α- and β-subunits also form an (αβ)2 structure in solution. Interestingly, only one of these AGAs subunits (α for AtAGA and β for LhAGA) is glycosylated instead of the two subunits for lysosomal human AGA (hAGA), and these glycosylations are partially resistant to PGNase F treatment. The two venom AGAs are secreted as fully activated enzymes, they have a similar aspartylglucosaminidase activity and are both also efficient asparaginases. Once AGAs are injected into the larvae of the Drosophila melanogaster host, the asparaginase activity may play a role in modulating their physiology. Altogether, our data provide new elements for a better understanding of the secretion and the role of venom AGAs as virulence factors in the parasitoid wasps' success.