title: A female-specific pentraxin, CrOctin, bridges pattern recognition receptors to bacterial phosphoethanolamine.
abstract: Pathogen recognition and binding are crucial functions of innate immunity. It has been observed that the short pentraxin superfamily including C-reactive protein (CRP) and serum amyloid P component are pathogen pattern recognition receptors (PRR) in the plasma. We isolated and characterized a novel and distinctive pentraxin from the plasma of horseshoe crab, Carcinoscorpius rotundicauda, henceforth named CrOctin, which binds to bacteria via phosphoethanolamine (PE), a chemical component present on lipid A and core polysaccharide moieties of bacterial lipopolysaccharide (LPS). Infection enhances the formation of the PRR interactome constituting CrOctin, CRP and galactose-binding protein. In particular, infection increases the affinity of CRP to CrOctin by 1000-fold. Furthermore, we observed that by binding to PE, CrOctin acts as a linker that bridges the PRR interactome to the inner core of LPS. On the other hand, under normal physiological conditions, binding of CrOctin to PE appears to obscure other PRR from interacting directly with PE. Interestingly, the cluster of "CrOctin-interactive PRR" is sex specific. We report, for the first time, the change in PRR protein profiles with a distinctive gender difference during Pseudomonas infection.
authors.affiliation: Department of Biological Sciences, National University of Singapore, Singapore.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.forename: P Miang Lon
authors.initials: PM
authors.lastname: Ng
authors.forename: Bow
authors.initials: B
authors.lastname: Ho
authors.forename: Jeak Ling
authors.initials: JL
authors.lastname: Ding
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002097:C-Reactive Protein / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D004983:Ethanolamines / Q000737:chemistry*; D005260:Female; D006458:Hemolymph / Q000737:chemistry; D006737:Horseshoe Crabs / Q000737:chemistry / Q000276:immunology*; D008070:Lipopolysaccharides / Q000737:chemistry / Q000276:immunology*; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D011485:Protein Binding; D025941:Protein Interaction Mapping; D011550:Pseudomonas aeruginosa / Q000737:chemistry; D051192:Receptors, Pattern Recognition / Q000097:blood / Q000235:genetics / Q000502:physiology*; D019779:Salmonella enterica / Q000737:chemistry; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012727:Sex Characteristics
chemical_list: C526789:CrOctin protein, Carcinoscorpius rotundicauda; D004983:Ethanolamines; D008070:Lipopolysaccharides; D051192:Receptors, Pattern Recognition; C005448:phosphorylethanolamine; D002097:C-Reactive Protein