Interactions between galectin-3 and Mac-2-binding protein mediate cell-cell adhesion.
Galectin-3 is a beta-galactoside-specific lectin implicated in diverse processes involved in cellular interactions. Recently, the Mac-2-binding protein, a heavily N-glycosylated secreted protein with a subunit Mr of 97,000, was identified as its ligand. The present study characterizes the interaction between galectin-3 and Mac-2-binding protein in whole cells and measures their relative expression levels. Incubation of A375 cells with affinity-purified Mac-2-binding protein resulted in its binding to galectin-3 on the cell surface in a specific carbohydrate-dependent manner. Mac-2-binding protein also induced homotypic cell aggregation, which was inhibited by lactose or Fab' fragments of an anti-galectin-3 antibody. Northern blotting analysis revealed differences in the transcriptional regulation of galectin-3 and Mac-2-binding protein. These results provide the first direct evidence for a Mac-2-binding protein function and suggest that it may play a role in tumor cell embolization during metastasis through interaction with galectin-3.
Inohara
H
H
Tumor Progression and Metastasis Program, Karmanos Cancer Institute, Wayne State University, Detroit, Michigan 48201, USA.
Akahani
S
S
Koths
K
K
Raz
A
A
D000943:Antigens, Differentiation / Q000235:genetics / Q000378:metabolism*; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D015152:Blotting, Northern; D001943:Breast Neoplasms / Q000473:pathology; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology*; D002449:Cell Aggregation; D018076:DNA, Complementary / Q000235:genetics; D005260:Female; D037502:Galectin 3; D015972:Gene Expression Regulation, Neoplastic; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008545:Melanoma / Q000473:pathology; D009360:Neoplastic Cells, Circulating; D011485:Protein Binding; D016326:Extracellular Matrix Proteins
D000943:Antigens, Differentiation; D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor; D002352:Carrier Proteins; D018076:DNA, Complementary; D037502:Galectin 3; D006023:Glycoproteins; C081856:LGALS3BP protein, human; D016326:Extracellular Matrix Proteins