title: Characterization of a novel Manduca sexta beta-1, 3-glucan recognition protein (βGRP3) with multiple functions.
abstract: Recognition of pathogens by insect pattern recognition receptors is critical to mount effective immune responses. In this study, we reported a new member (βGRP3) of the β-1, 3-glucan recognition protein (βGRP) family from the tobacco hornworm Manduca sexta. Unlike other members of the M. sexta βGRP family proteins, which contain an N-terminal small glucan binding domain and a C-terminal large glucanase-like domain, βGRP3 is 40-45 residues shorter at the N-terminus and lacks the small glucan binding domain. The glucanase-like domain of βGRP3 is most similar to that of M. sexta microbe binding protein (MBP) with 78% identity. βGRP3 transcript was mainly expressed in the fat body, and both its mRNA and protein levels were not induced by microorganisms in larvae. Recombinant βGRP3 purified from Drosophila S2 cells could bind to several Gram-negative and Gram-positive bacteria and yeast, as well as to laminarin (β-1, 3-glucan), mannan, lipopolysaccharide (LPS), lipoteichoic acid (LTA), and meso-diaminopimelic acid (DAP)-type peptidoglycan (PG), but did not bind to Lysine-type PG. Binding of βGRP3 to laminarin could be competed well by free laminarin, mannan, LPS and LTA, but almost not competed by free PGs. Recombinant βGRP3 could agglutinate Bacillus cereus and Escherichia coli in a calcium-dependent manner and showed antibacterial (bacteriostatic) activity against B. cereus, novel functions that have not been reported for the βGRP family proteins before. M. sexta βGRP3 may serve as an immune surveillance receptor with multiple functions.
authors: School of Plant Protection, Anhui Agricultural University, Hefei, Anhui 230036, China; Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Road, Kansas City, MO 64110, USA.
authors: Xiang-Jun
authors: XJ
authors: Rao
authors: Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Road, Kansas City, MO 64110, USA.
authors: Xue
authors: X
authors: Zhong
authors: Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Road, Kansas City, MO 64110, USA; College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
authors: Xin-Yu
authors: XY
authors: Lin
authors: Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Road, Kansas City, MO 64110, USA; College of Animal Sciences, Fujian Agriculture and Forestry University, Fuzhou, Fujian 350002, China.
authors: Xiao-Hong
authors: XH
authors: Huang
authors: Division of Molecular Biology and Biochemistry, School of Biological Sciences, University of Missouri-Kansas City, 5007 Rockhill Road, Kansas City, MO 64110, USA. Electronic address: Yux@umkc.edu.
authors: Xiao-Qiang
authors: XQ
authors: Yu
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001409:Bacillus cereus / Q000378:metabolism; D001483:Base Sequence; D004156:Catechol Oxidase / Q000378:metabolism*; D004792:Enzyme Precursors / Q000378:metabolism*; D004926:Escherichia coli / Q000378:metabolism; D007113:Immunity, Innate; D019476:Insect Proteins / Q000276:immunology / Q000378:metabolism; D007814:Larva / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D008070:Lipopolysaccharides / Q000378:metabolism; D018402:Manduca / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D011485:Protein Binding; D016415:Sequence Alignment; D047071:beta-Glucans / Q000378:metabolism*
chemical_list: D004792:Enzyme Precursors; D019476:Insect Proteins; D008070:Lipopolysaccharides; D047071:beta-Glucans; D004156:Catechol Oxidase
keywords: Agglutination; Antibacterial; Innate immunity; Microbial cell walls; βGRP