PMID:21296155

Citation	Wang, Y, Sumathipala, N, Rayaprolu, S and Jiang, H (2011) Recognition of microbial molecular patterns and stimulation of prophenoloxidase activation by a β-1,3-glucanase-related protein in Manduca sexta larval plasma. Insect Biochem. Mol. Biol. 41:322-31
Abstract	Detection of pathogenic invaders is the essential first step of a successful defense response in multicellular organisms. In this study, we have identified a new member of the β-1,3-glucanase-related protein superfamily from the tobacco hornworm Manduca sexta. This protein, designated microbe binding protein (MBP), is 61% identical in sequence to Bombyx mori Gram-negative bacteria binding protein, but only 34-36% identical to M. sexta β-1,3-glucan recognition protein-1 and 2. Its mRNA levels were strongly up-regulated in hemocytes and fat body of immune challenged larvae, along with an increase in concentration of the plasma protein. We expressed M. sexta MBP in a baculovirus-insect cell system. The purified protein associated with intact bacteria and fungi. It specifically bound to lipoteichoic acid, lipopolysaccharide, diaminopimelic acid-type peptidoglycans (DAP-PGs) from Escherichia coli and Bacillus subtilis, but less so to laminarin or Lys-type PG from Staphylococcus aureus. The complex binding pattern was influenced by other plasma factors and additional microbial surface molecules. After different amounts of MBP had been incubated with larval plasma on ice, a concentration-dependent increase in phenoloxidase (PO) activity occurred in the absence of any microbial elicitor. The activity increase was also observed in the mixture of plasma and a bacterial or fungal cell wall component. The prophenoloxidase (proPO) activation became more prominent when DAP-PGs, Micrococcus luteus Lys-PG, or lipoteichoic acid was included in the mixture of MBP and plasma. Statistic analysis suggested that a synergistic enhancement of proPO activation was caused by an interaction between MBP and these elicitors, but not S. aureus Lys-PG, lipopolysaccharide, curdlan, or laminarin. These data indicate that M. sexta MBP is a component of the surveillance mechanism and, by working together with other pattern recognition molecules and serine proteinases, triggers the proPO activation system.
Links	PubMed PMC3066292 Online version:10.1016/j.ibmb.2011.01.010
Keywords	Amino Acid Sequence; Animals; Base Sequence; Catechol Oxidase/genetics; Catechol Oxidase/metabolism; Enzyme Activation; Enzyme Precursors/genetics; Enzyme Precursors/metabolism; Gene Expression; Glucan 1,3-beta-Glucosidase/genetics; Glucan 1,3-beta-Glucosidase/metabolism; Hemocytes/metabolism; Insect Proteins/genetics; Insect Proteins/metabolism; Isoenzymes/genetics; Isoenzymes/metabolism; Larva/genetics; Larva/immunology; Larva/metabolism; Manduca/genetics; Manduca/immunology; Manduca/metabolism; Micrococcus luteus; Molecular Sequence Data; Phylogeny; Polysaccharides, Bacterial/immunology; Polysaccharides, Bacterial/metabolism; Protein Binding; RNA, Messenger/analysis; RNA, Messenger/biosynthesis; Sequence Alignment; beta-Glucans/metabolism
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
MANSE:G9G7R0	Contributes to	GO:0004503: monophenol monooxygenase activity	ECO:0000314:		F		Beta-1,3-glucanase increases prophenoloxidase activation in manduca sexta larval plasma.	complete

References

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