title: Galectin-4 binds to sulfated glycosphingolipids and carcinoembryonic antigen in patches on the cell surface of human colon adenocarcinoma cells.
abstract: Galectin-4, a member of the galectin family, is expressed in the epithelium of the alimentary tract. It has two tandemly repeated carbohydrate recognition domains and specifically binds to an SO3- -->3Galbeta1-->3GalNAc pyranoside with high affinity (Ideo, H., Seko, A., Ohkura, T., Matta, K. L., and Yamashita, K. (2002) Glycobiology 12, 199-208). In this study, we found that galectin-4 binds to glycosphingolipids carrying 3-O-sulfated Gal residues, such as SB1a, SM3, SM4s, SB2, SM2a, and GM1, but not to glycosphingolipids with 3-O-sialylated Gal, such as sLc4Cer, snLc4Cer, GM3, GM2, and GM4, using both an enzyme-linked immunosorbent assay and a surface plasmon resonance assay. A confocal immunocytochemical assay showed that galectin-4 was colocalized with SB1a, GM1, and carcinoembryonic antigen (CEA) in the patches on the cell surface of human colon adenocarcinoma CCK-81 and LS174T cells. This localization was distinct from caveolin/VIP21 localization. Furthermore, immobilized galectin-4 promoted adhesion of CCK-81 cells through the sulfated glycosphingolipid, SB1a. CEA also bound to galectin-4 with KD value of 2 x 10(-8) m by surface plasmon resonance and coimmunoprecipitated with galectin-4 in LS174T cell lysates. These findings suggest that SB1a and CEA in the patches on the cell surface of human colon adenocarcinoma cells could be biologically important ligands for galectin-4.
authors.affiliation: Department of Biochemistry, Sasaki Institute, 2-2, Kanda-Surugadai, Chiyoda-ku, Tokyo 101-0062 , Japan.
authors.forename: Hiroko
authors.initials: H
authors.lastname: Ideo
authors.forename: Akira
authors.initials: A
authors.lastname: Seko
authors.forename: Katsuko
authors.initials: K
authors.lastname: Yamashita
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism; D002240:Carbohydrate Sequence; D002241:Carbohydrates / Q000737:chemistry; D002272:Carcinoembryonic Antigen / Q000737:chemistry*; D002448:Cell Adhesion; D045744:Cell Line, Tumor; D003110:Colonic Neoplasms / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D037541:Galectin 4 / Q000737:chemistry / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism; D006017:Glycolipids / Q000737:chemistry; D006028:Glycosphingolipids / Q000737:chemistry*; D006801:Humans; D007150:Immunohistochemistry; D047468:Immunoprecipitation; D007700:Kinetics; D008024:Ligands; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D013455:Sulfur / Q000737:chemistry; D020349:Surface Plasmon Resonance; D013997:Time Factors
chemical_list: D002241:Carbohydrates; D002272:Carcinoembryonic Antigen; D037541:Galectin 4; D006017:Glycolipids; D006028:Glycosphingolipids; D008024:Ligands; D013455:Sulfur; D005982:Glutathione Transferase