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Carbohydrate recognition by a natural killer cell receptor, Ly-49C
1Terry Fox Laboratory, British Columbia Cancer Agency, Vancouver, Canada.
The Journal of Biological Chemistry
|April 28, 1995
Summary
Natural killer cell receptors, like Ly-49C, can recognize specific carbohydrates. This study shows Ly-49C binds sulfated glycans, indicating a role for carbohydrate recognition in natural killer cell function.
Area of Science:
- Immunology
- Glycobiology
- Cell Biology
Background:
- Ly-49 proteins are type II transmembrane receptors with C-type lectin domains.
- Ly-49A and Ly-49C are expressed on natural killer (NK) cells and bind to MHC class I molecules.
- The precise recognition mechanisms of Ly-49 receptors are not fully elucidated.
Purpose of the Study:
- To investigate the potential for Ly-49C to mediate carbohydrate recognition.
- To identify specific carbohydrate structures recognized by Ly-49C.
- To understand the role of carbohydrate binding in Ly-49C-mediated cellular interactions.
Main Methods:
- Assessed Ly-49C-mediated cell adhesion using various sulfated glycans as inhibitors.
- Utilized antibody 5E6 to confirm direct protein-carbohydrate interactions with Ly-49C.
- Employed enzymatic treatment of target cells to identify key carbohydrate moieties involved in adhesion.
Main Results:
- Sulfated glycans (fucoidan, lambda-carrageenan, dextran sulfate) potently inhibited Ly-49C adhesion.
- Inhibitory polysaccharides also blocked 5E6 antibody binding to Ly-49C, confirming direct interaction.
- Ly-49C adhesion was not sialic acid-dependent but was significantly reduced after fucosidase treatment.
Conclusions:
- Ly-49C exhibits specific carbohydrate recognition capabilities, particularly for sulfated glycans.
- Fucose appears to be a critical component in Ly-49C-mediated cell adhesion.
- These findings highlight a significant role for carbohydrate recognition in the function of natural killer cell receptors.