Selective N-glycan editing on living cell surfaces to probe glycoconjugate function

Area of Science:

• Glycobiology
• Cell Biology
• Biochemistry

Background:

• Cell surface glycosylation is highly heterogeneous, complicating the study of glycan-mediated biological functions.
• Ambiguous conclusions often arise from the complex and varied nature of cellular glycans.

Purpose of the Study:

• To develop a chemoenzymatic approach for selective N-glycan editing on living cells.
• To enable precise investigation of carbohydrate-mediated functions by creating homogeneous glycan structures.
• To correlate specific N-glycan structures with opioid receptor delta 1 (OPRD1) functions.

Main Methods:

• A two-step chemoenzymatic strategy involving a 'delete' step to remove specific N-glycoforms and an 'insert' step to reassemble defined N-glycans.
• Utilizing the Lec4 CHO cell line expression system for glycan remodeling.
• Investigating N-glycan-subtype-selective remodeling and imaging with distinct monosaccharide motifs.

Main Results:

• Successfully demonstrated N-glycan-subtype-selective editing on living cells.
• Achieved homogeneous oligosaccharide structures on glyco-edited cells.
• Correlated specific glycostructures of OPRD1 with receptor dimerization, signaling, and internalization.

Conclusions:

• The developed two-step glycan-editing approach allows for precise control over cell surface N-glycans.
• Homogeneous glycan structures facilitate accurate understanding of carbohydrate-involved biological processes.
• This method provides new insights into the functional roles of OPRD1 glycosylation.