C-Type Lectin Family: Overview

Abstract

Members of the C-type lectin family of glycan-binding receptors in animals contain modular carbohydrate recognition domains (CRDs) that form a subset of a larger structural class of protein modules designated C-type lectin-like domains. Two broad categories of C-type CRDs bind either mannose and related sugars or galactose and related sugars at the Ca-binding site. Small changes in sequence have resulted in switches in this primary specificity. Additional selectivity for more complex glycans results from secondary binding interactions. In mammals, C-type CRDs recognize either endogenous glycans or sugars on potentially pathogenic microorganisms. Recognition of endogenous sugar tags on cell surfaces can initiate cell adhesion and signaling, while binding to sugars on serum glycoproteins can initiate clearance from serum. C-type CRDs that bind to sugars on the surfaces of pathogens form part of the innate immune system.