A snake-like serine proteinase (PmSnake) activates prophenoloxidase-activating system in black tiger shrimp Penaeus monodon. (February 2017)

• Record Type: Journal Article
• Authors: Monwan, Warunthorn; Amparyup, Piti; Tassanakajon, Anchalee
• Is Part Of: Developmental and comparative immunology. Volume 67(2017)
• Page Start: 229
• Page End: 238
• Publication Date: 2017-02
• Subjects: Shrimp -- Peneaus monodon -- Prophenoloxidase -- Snake-like serine proteinase; Immunology -- Periodicals; Developmental immunology -- Periodicals; 616.079
• DOI: 10.1016/j.dci.2016.09.016
• Languages: English
• ISSNs: 0145-305X

Abstract

Abstract: Clip domain serine proteinases (ClipSPs) play critical roles in the activation of proteolytic cascade in invertebrate immune systems including the prophenoloxidase (proPO) activating system. In this study, we characterized a snake-like serine protease, namely Pm Snake, from the shrimp Penaeus monodon which has previously been identified based on the subtractive cDNA library of proPO double-stranded RNA (dsRNA)-treated hemocytes. An open reading frame of Pm Snake contains 1068 bp encoding a predicted protein of 355 amino acid residues with a putative signal peptide of 22 amino acids and two conserved domains (N-terminal clip domain and C-terminal trypsin-like serine proteinase domain). Sequence analysis revealed that Pm Snake was closest to the Ae Snake from ant Acromyrmex echinatior (53% similarity), but was quite relatively distant from other shrimp Pm clipSPs. Pm Snake transcript was mainly expressed in shrimp hemocytes and up-regulated after systemic Vibrio harveyi infection indicating that it is an immune-responsive gene. Suppression of Pm Snake expression by dsRNA interference reduced both transcript and protein levels leading to a reduction of the hemolymph phenoloxidase (PO) activity (36%), compared to the control, suggesting that the Pm Snake functions as a clip-SP in shrimp proPO system. Western blot analysis using anti- Pm Snake showed that the Pm Snake was detected in hemocytes but not in cell-free plasma. In vitro PO activity and serine proteinase activity assays showed that adding r Pm Snake into the shrimp hemolymph could increase PO activity as well as serine proteinase activity suggesting that the r Pm Snake activates the proPO system via serine proteinase cascade. Highlights: Shrimp Pm Snake is closely related to insect snake-proteinases. Pm Snake is an immune responsive gene. Pm Snake participates in the proPO system.