title: The two endocytic pathways mediated by the carbohydrate recognition domain and regulated by the collagen-like domain of galectin-3 in vascular endothelial cells.
abstract: Galectin-3 plays an important role in endothelial morphogenesis and angiogenesis. We investigated the endocytosis of galectin-3 in human vascular endothelial cells and showed that galectin-3 could associate with and internalized into the cells in a carbohydrate-dependent manner. Our work also revealed that galectin-3 was transported to the early/recycling endosomes and then partitioned into two routes - recycling back to the plasma membrane or targeting to the late endosomes/lysosomes. Various N- and C-terminal truncated forms of galectin-3 were constructed and compared with the full-length protein. These comparisons showed that the carbohydrate-recognition domain of galectin-3 was required for galectin-3 binding and endocytosis. The N-terminal half of the protein, which comprises the N-terminal leader domain and the collagen-like internal repeating domain, could not mediate binding and endocytosis alone. The collagen-like domain, although it was largely irrelevant to galectin-3 trafficking to the early/recycling endosomes, was required for targeting galectin-3 to the late endosomes/lysosomes. In contrast, the leader domain was irrelevant to both binding and intracellular trafficking. The data presented in this study correlate well with different cellular behaviors induced by the full-length and the truncated galectin-3 and provide an alternative way of understanding its angiogenic mechanisms.
authors.affiliation: School of Life Sciences, Northeast Normal University, Changchun, PR China.
authors.forename: Xiaoge
authors.initials: X
authors.lastname: Gao
authors.forename: Dan
authors.initials: D
authors.lastname: Liu
authors.forename: Yuying
authors.initials: Y
authors.lastname: Fan
authors.forename: Xinzhi
authors.initials: X
authors.lastname: Li
authors.forename: Huiting
authors.initials: H
authors.lastname: Xue
authors.forename: Yingyun
authors.initials: Y
authors.lastname: Ma
authors.forename: Yifa
authors.initials: Y
authors.lastname: Zhou
authors.forename: Guihua
authors.initials: G
authors.lastname: Tai
mesh_terms: D000818:Animals; D016466:CHO Cells; D050260:Carbohydrate Metabolism; D002462:Cell Membrane / Q000378:metabolism; D003094:Collagen / Q000737:chemistry*; D006224:Cricetinae; D003412:Cricetulus; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D037502:Galectin 3 / Q000737:chemistry* / Q000378:metabolism*; D061307:Human Umbilical Vein Endothelial Cells / Q000166:cytology* / Q000378:metabolism*; D006801:Humans; D042541:Intracellular Space / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism; D055806:Microvessels / Q000166:cytology; D017434:Protein Structure, Tertiary; D020449:Repetitive Sequences, Amino Acid; D013696:Temperature
chemical_list: D037502:Galectin 3; D003094:Collagen