TY - JOUR
T1 - Complex N-glycans are the major ligands for galectin-1, -3, and -8 on Chinese hamster ovary cells
AU - Patnaik, Santosh Kumar
AU - Potvin, Barry
AU - Carlsson, Susanne
AU - Sturm, David
AU - Leffler, Hakon
AU - Stanley, Pamela
N1 - Funding Information:
The assistance of Subha Sundaram and Yuning Rian is gratefully acknowledged. This work was supported by grant
PY - 2006/4
Y1 - 2006/4
N2 - Galectins are implicated in a large variety of biological functions, many of which depend on their carbohydrate-binding ability. Fifteen members of the family have been identified in vertebrates based on binding to galactose (Gal) that is mediated by one or two, evolutionarily conserved, carbohydrate-recognition domains (CRDs). Variations in glycan structures expressed on glycoconjugates at the cell surface may, therefore, affect galectin binding and functions. To identify roles for different glycans in the binding of the three types of mammalian galectins to cells, we performed fluorescence cytometry at 4deg;C with recombinant rat galectin-1, human galectin-3, and three forms of human galectin-8, to Chinese hamster ovary (CHO) cells and 12 different CHO glycosylation mutants. All galectin species bound to parent CHO cells and binding was inhibited >90% by 0.2 M lactose. Galectin-8 isoforms with either a long or a short inter-CRD linker bound similarly to CHO cells. However, a truncated form of galectin-8 containing only the N-terminal CRD bound only weakly to CHO cells and the C-terminal galectin-8 CRD exhibited extremely low binding. Binding of the galectins to the different CHO glycosylation mutants revealed that complex N-glycans are the major ligands for each galectin except the N-terminal CRD of galectins-8, and also identified some fine differences in glycan recognition. Interestingly, increased binding of galectin-1 at 4deg;C correlated with increased propidium iodide (PI) uptake, whereas galectin-3 or -8 binding did not induce permeability to PI. The CHO glycosylation mutants with various repertoires of cell surface glycans are a useful tool for investigating galectin-cell interactions as they present complex and simple glycans in a natural mixture of multivalent protein and lipid glycoconjugates anchored in a cell membrane.
AB - Galectins are implicated in a large variety of biological functions, many of which depend on their carbohydrate-binding ability. Fifteen members of the family have been identified in vertebrates based on binding to galactose (Gal) that is mediated by one or two, evolutionarily conserved, carbohydrate-recognition domains (CRDs). Variations in glycan structures expressed on glycoconjugates at the cell surface may, therefore, affect galectin binding and functions. To identify roles for different glycans in the binding of the three types of mammalian galectins to cells, we performed fluorescence cytometry at 4deg;C with recombinant rat galectin-1, human galectin-3, and three forms of human galectin-8, to Chinese hamster ovary (CHO) cells and 12 different CHO glycosylation mutants. All galectin species bound to parent CHO cells and binding was inhibited >90% by 0.2 M lactose. Galectin-8 isoforms with either a long or a short inter-CRD linker bound similarly to CHO cells. However, a truncated form of galectin-8 containing only the N-terminal CRD bound only weakly to CHO cells and the C-terminal galectin-8 CRD exhibited extremely low binding. Binding of the galectins to the different CHO glycosylation mutants revealed that complex N-glycans are the major ligands for each galectin except the N-terminal CRD of galectins-8, and also identified some fine differences in glycan recognition. Interestingly, increased binding of galectin-1 at 4deg;C correlated with increased propidium iodide (PI) uptake, whereas galectin-3 or -8 binding did not induce permeability to PI. The CHO glycosylation mutants with various repertoires of cell surface glycans are a useful tool for investigating galectin-cell interactions as they present complex and simple glycans in a natural mixture of multivalent protein and lipid glycoconjugates anchored in a cell membrane.
KW - CHO
KW - Galectin
KW - Glycan recognition
KW - Glycosylation mutants
KW - Lectin
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U2 - 10.1093/glycob/cwj063
DO - 10.1093/glycob/cwj063
M3 - Article
C2 - 16319083
AN - SCOPUS:33645102970
SN - 0959-6658
VL - 16
SP - 305
EP - 317
JO - Glycobiology
JF - Glycobiology
IS - 4
ER -