Identification and characterization of multiple beta-glucan binding proteins in the Pacific oyster, Crassostrea gigas.
The present study reports on the characterization of two cDNAs coding beta-glucan binding proteins (betaGBPs), designated as Cg-betaGBP-1 and Cg-betaGBP-2, from the Pacific oyster, Crassostrea gigas. Cg-betaGBP-1 consists of 555 amino acid residues and possesses two possible integrin recognition sites. The other protein, Cg-betaGBP-2, is composed of 447 amino acid residues without integrin recognition sites. Domain structures of both Cg-betaGBPs are similar to other invertebrate betaGBPs, but phylogenetic positions and major expression tissues for these proteins are different. Cg-betaGBP-1 is expressed in circulatory hemocytes and Cg-betaGBP-2 in digestive glands. Functional assays using recombinant proteins revealed that Cg-betaGBP-2 enhanced the phenoloxidase (PO) activity of hemocyte suspensions under the presence of laminarin, but Cg-betaGBP-1 did not show this enhancement. It is suggested that Cg-betaGBPs in the Pacific oyster have evolved to obtain different immunological functions. Cg-betaGBP-1 possibly evolved for hemocyte-related functions through integrin, and Cg-betaGBP-2 for the PO activation system.
Itoh
Naoki
N
Aquacultural Biology Laboratory, Graduate School of Agricultural Science, Tohoku University, Tsutsumidori Amamiya-machi, Aoba-ku, Sendai, Miyagi 981-8555, Japan. nitoh@bios.tohoku.ac.jp
Kamitaka
Ryo
R
Takahashi
Keisuke G
KG
Osada
Makoto
M
D000818:Animals; D002352:Carrier Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D049896:Crassostrea / Q000502:physiology*; D004064:Digestive System / Q000276:immunology / Q000378:metabolism*; D019143:Evolution, Molecular; D020869:Gene Expression Profiling; D015971:Gene Expression Regulation, Enzymologic / Q000276:immunology; D005936:Glucans; D006434:Hemocytes / Q000276:immunology / Q000378:metabolism*; D037102:Lectins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D014442:Monophenol Monooxygenase / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D011134:Polysaccharides / Q000378:metabolism; D017434:Protein Structure, Tertiary / Q000235:genetics
D002352:Carrier Proteins; D005936:Glucans; D037102:Lectins; D011134:Polysaccharides; C037937:glucan-binding proteins; C008247:laminaran; D014442:Monophenol Monooxygenase