title: CfLec-3 from scallop: an entrance to non-self recognition mechanism of invertebrate C-type lectin.
abstract: A C-type lectin (CfLec-3) from Chlamys farreri with three carbohydrate-recognition domains (CRDs) was selected to dissect the possible mechanisms of PAMP binding and functional differentiation of invertebrate lectins. CfLec-3 distributed broadly, and its mRNA expression in hemocytes increased significantly after stimulations with LPS, PGN or β-glucan, but not poly(I:C). The recombinant CfLec-3 (rCfLec-3) could bind PAMPs and several microbes. rCfLec-3 mediated hemocytes phagocytosis against Escherichia coli and encapsulation towards agarose beads. Obvious functional differentiation occurred among the three CRDs, as CRD1 exhibited higher activity to bind PAMPs, while CRD2/3 were expert in promoting hemocyte mediated opsonisation. The tertiary structural differences were suspected to be associated with such functional differentiation. PAMP binding abilities of CfLec-3 were determined by Ca(2+)-binding site 2 motif. When Pro in this motif of each CRD was mutated into Ser, their PAMP binding abilities were deprived absolutely. rCRD2 acquired mannan binding capability when its EPD was replaced by EPN, but lost when EPN in rCRD3 was changed into EPD. The Pro in Ca(2+)-binding site 2 was indispensable for PAMPs binding, while Asn was determinant for specific binding to mannan. It shed new insight into PAMPs binding mechanism of invertebrate C-type lectins and their functional differentiation.
authors.affiliation: 1] Key laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China [2] University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Jialong
authors.initials: J
authors.lastname: Yang
authors.affiliation: 1] Key laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China [2] University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Mengmeng
authors.initials: M
authors.lastname: Huang
authors.affiliation: Key laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors.forename: Huan
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Key laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.affiliation: 1] Key laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China [2] University of Chinese Academy of Sciences, Beijing, China.
authors.forename: Leilei
authors.initials: L
authors.lastname: Wang
authors.affiliation: Key laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China.
authors.forename: Limei
authors.initials: L
authors.lastname: Qiu
authors.affiliation: 1] Key laboratory of Experimental Marine Biology, Institute of Oceanology, Chinese Academy of Sciences, Qingdao, China [2] Dalian Ocean University, Dalian 116023, China.
authors.forename: Linsheng
authors.initials: L
authors.lastname: Song
mesh_terms: D000818:Animals; D004926:Escherichia coli / Q000276:immunology*; D005260:Female; D006434:Hemocytes / Q000276:immunology*; D037181:Lectins, C-Type / Q000235:genetics / Q000276:immunology*; D008070:Lipopolysaccharides / Q000276:immunology; D000069452:Pathogen-Associated Molecular Pattern Molecules / Q000276:immunology*; D049897:Pectinidae / Q000378:metabolism; D010457:Peptidoglycan / Q000276:immunology; D010587:Phagocytosis / Q000276:immunology; D011070:Poly I-C / Q000276:immunology; D011485:Protein Binding; D051381:Rats; D017208:Rats, Wistar; D017634:Self Tolerance / Q000276:immunology*; D047071:beta-Glucans / Q000276:immunology
chemical_list: D037181:Lectins, C-Type; D008070:Lipopolysaccharides; D000069452:Pathogen-Associated Molecular Pattern Molecules; D010457:Peptidoglycan; D047071:beta-Glucans; D011070:Poly I-C