Recombinant Human CLEC-1 Protein, CF

CLEC-1 (C-type lectin-like receptor-1) is a type 2 transmembrane protein that belongs to the Dectin-1 family of C-type lectins (1, 2). It consists of a 52 amino acid (aa) cytoplasmic domain, a 21 aa transmembrane segment, and a 207 aa extracellular domain (ECD) (3). The ECD contains a carbohydrate recognition domain (CRD) that includes cysteine residues with conserved spacing (4). In other C-type lectins, these cysteines form intrachain disulfide bonds that stabilize the CRD protein fold (4). CLEC-1 is a nonclassical C-type lectin in that its CRD lacks consensus amino acids which mediate calcium dependent carbohydrate binding in other C-type lectins (2, 3). The cytoplasmic domain contains one tyrosine, multiple serine and threonine, and a cluster of aspartic acid residues. The CLEC-1, CLEC-2, Dectin-1, and LOX-1 genes are located within the NK gene complex that also encodes several receptors involved in regulating NK cell activation (3, 5). CLEC-1 is most highly expressed in activated dendritic cells and at lower levels in endothelial cells and monocytes (3, 5). Within the CRD, human CLEC-1 shares 65% aa sequence identity with mouse and rat CLEC-1 and 26% - 36% with the other human Dectin-1 family lectins CLEC-2, CLEC9A, CLEC12B, Dectin-1, LOX-1, and MICL.