Binding-site geometry and flexibility in DC-SIGN demonstrated with surface force measurements.

The dendritic cell receptor DC-SIGN mediates pathogen recognition by binding to glycans characteristic of pathogen surfaces, including those found on HIV. Clustering of carbohydrate-binding sites in the receptor tetramer is believed to be critical for targeting of pathogen glycans, but the arrangement of these sites remains poorly understood. Surface force measurements between apposed lipid bilayers displaying the extracellular domain of DC-SIGN and a neoglycolipid bearing an oligosaccharide ligand provide evidence that the receptor is in an extended conformation and that glycan docking is associated with a conformational change that repositions the carbohydrate-recognition domains during ligand binding.

Widely divergent biochemical properties of the complete set of mouse DC-SIGN-related proteins.

The mouse genome sequence has been examined to identify the complete set of proteins related to the human glycanbinding receptor, DC-SIGN. In addition to five SIGNR proteins previously described, a pseudogene, encoding a hypothetical SIGNR6, and a further two expressed proteins, SIGNR7 and SIGNR8, have been identified. The ligand-binding properties of these novel proteins and of the previously described mouse SIGNs have been systematically investigated in order to define the mouse proteins that most resemble human DC-SIGN and DC-SIGNR.

Polymorphisms in human langerin affect stability and sugar binding activity.

Langerhans cells are specialized skin dendritic cells that take up and degrade antigens for presentation to the immune system. Langerin, a cell surface C-type lectin of Langerhans cells, can be internalized and accumulates in Birbeck granules, subdomains of the endosomal recycling compartment that are specific to Langerhans cells. Langerin binds and mediates uptake and degradation of glycoconjugates containing mannose and related sugars.