Cloning and Characterization of the Hakata Antigen, a Member of the Ficolin/Opsonin p35 Lectin Family

• Published in: The Journal of biological chemistry Vol. 273; no. 33; pp. 20721 - 20727
• Main Authors: Sugimoto, Rie, Yae, Yoshiaki, Akaiwa, Mina, Kitajima, Shigetaka, Shibata, Yosaburo, Sato, Hiroyuki, Hirata, Joji, Okochi, Kazuo, Izuhara, Kenji, Hamasaki, Naotaka
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 14.08.1998; American Society for Biochemistry and Molecular Biology
• Subjects: Amino Acid Sequence; Base Sequence; Carrier Proteins - genetics; Carrier Proteins - metabolism; Cell Line; Cloning, Molecular; DNA, Complementary; Ficolins; Glycoproteins - genetics; Glycoproteins - metabolism; Humans; Lectins; Microscopy, Electron; Molecular Sequence Data; Opsonin Proteins - genetics; Opsonin Proteins - metabolism; Sequence Homology, Amino Acid; Transfection
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1074/jbc.273.33.20721

The Hakata antigen is a novel, thermolabile β2-macroglycoprotein that reacts with sera from patients suffering from systemic lupus erythematosus. In this study we present the structure and the function of the Hakata antigen. We have identified cDNA clones encoding the Hakata antigen and analyzed its function. The cDNA included a possible open reading frame of 897 nucleotides, encoding 299 amino acids. The Hakata antigen consisted of a collagen-like domain in the middle section and a fibrinogen-like domain in the COOH terminus, both of which are homologous to human ficolin-1 and opsonin P35, indicating that these three molecules form a distinct family. The molecular mass of the Hakata antigen expressed in transfected cells was 35 kDa under reduced conditions, and it formed ladder bands under nonreducing conditions compatible with the previous result that the Hakata antigen exists in serum as homopolymers. Purified Hakata antigen sustained lectin activity, showing affinity with GalNAc, GlcNAc, d-fucose as mono/oligosaccharide, and lipopolysaccharides from Salmonella typhimurium andSalmonella minnesota. These results suggest that the Hakata antigen, a new member of the ficolin/opsonin P35 family, plays a role in the serum exerting lectin activity under physiological conditions.