A serine proteinase homolog venom protein from an endoparasitoid wasp inhibits melanization of the host hemolymph.
Activation of prophenoloxidase (proPO) in insects is a defense mechanism against intruding microorganisms and parasites. Pattern recognition molecules induce activation of an enzymatic cascade involving serine proteinases, which leads to the conversion of proPO to active phenoloxidase (PO). Phenolic compounds produced by pPO-activation are toxic to invaders. Here, we describe the isolation of a venom protein from the parasitoid, Cotesia rubecula, injected into the host, Pieris rapae, which is homologous to serine proteinase homologs (SPH). The data presented here indicate that the protein interferes with the proteolytic cascade, which under normal circumstances leads to the activation of proPO and melanin formation.
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002080:Butterflies / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D005260:Female; D017353:Gene Deletion; D006458:Hemolymph / Q000187:drug effects / Q000378:metabolism*; D007814:Larva / Q000187:drug effects; D008543:Melanins / Q000037:antagonists & inhibitors*; D008969:Molecular Sequence Data; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors / Q000378:metabolism; D011994:Recombinant Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012697:Serine Endopeptidases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D014862:Wasp Venoms / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism / Q000494:pharmacology*; D014863:Wasps / Q000737:chemistry*
D004791:Enzyme Inhibitors; D008543:Melanins; D011994:Recombinant Proteins; D014862:Wasp Venoms; D014442:Monophenol Monooxygenase; D012697:Serine Endopeptidases