title: Carbohydrate-recognition domains of galectin-9 are involved in intermolecular interaction with galectin-9 itself and other members of the galectin family.
abstract: Galectin-9 (Gal-9) is a tandem-repeat-type member of the galectin family associated with diverse biological processes, such as apoptosis, cell aggregation, and eosinophil chemoattraction. Although the detailed sugar-binding specificity of Gal-9 has been elucidated, molecular mechanisms that underlie these functions remain to be investigated. During the course of our binding study by affinity chromatography and surface plasmon resonance (SPR) analysis, we found that human Gal-9 interacts with immobilized Gal-9 in the protein-protein interaction mode. Interestingly, this intermolecular interaction strongly depended on the activity of the carbohydrate recognition domain (CRD), because the addition of potent saccharide inhibitors abolished the binding. The presence of multimers was also confirmed by Ferguson plot analysis of result of polyacrylamide gel electrophoresis and matrix-assisted laser-desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). Moreover, this intermolecular interaction was observed between Gal-9 and other galectin members, such as Gal-3 and Gal-8, but not Gal-1. Because such properties have not been reported yet, they may explain an unidentified mechanism underlying the diverse functions of Gal-9.
authors.affiliation: Department of Functional Glycomics, Life Science Research Center, National Institute of Advanced Industrial Science and Technology, 2217-14 Hayashi-machi, Takamatsu, Kagawa 761-0301, Japan. glycofun@med.kagawa-u.ac.jp
authors.forename: Nobumitsu
authors.initials: N
authors.lastname: Miyanishi
authors.forename: Nozomu
authors.initials: N
authors.lastname: Nishi
authors.forename: Hiroko
authors.initials: H
authors.lastname: Abe
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Kashio
authors.forename: Rika
authors.initials: R
authors.lastname: Shinonaga
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Nakakita
authors.forename: Wataru
authors.initials: W
authors.lastname: Sumiyoshi
authors.forename: Akira
authors.initials: A
authors.lastname: Yamauchi
authors.forename: Takanori
authors.initials: T
authors.lastname: Nakamura
authors.forename: Mitsuomi
authors.initials: M
authors.lastname: Hirashima
authors.forename: Jun
authors.initials: J
authors.lastname: Hirabayashi
mesh_terms: D002846:Chromatography, Affinity; D037161:Galectins / Q000737:chemistry* / Q000302:isolation & purification; D006801:Humans; D007150:Immunohistochemistry; D009844:Oligosaccharides / Q000737:chemistry / Q000302:isolation & purification; D011506:Proteins / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013816:Thermodynamics
chemical_list: D037161:Galectins; C105032:LGALS9 protein, human; D009844:Oligosaccharides; D011506:Proteins