Dectin-1, also known as CLEC7A and the β-glucan receptor, is a 33kD type II transmembrane C-type lectin that participates in the innate immune response to fungal pathogens. Although Dectin-1 structurally resembles other CLEC molecules, it binds its ligands in a calcium-independent manner (1, 2). Mature human Dectin-1 consists of a short N-terminal ITAM-containing cytoplasmic tail, a transmembrane segment, and a C-terminal stalk with carbohydrate recognition domain (CRD) in the extracellular domain (3, 4). Alternate splicing generates one major splice form that lacks the stalk region (3-5). This isoform is expressed on the surface of monocytes, macrophages, myeloid DC, neutrophils, eosinophils, B cells, and CD4+ T cells (6). The CRD selectively binds β-glucan polymers, a major component of yeast and mycobacterial cell walls (5-7). Yeast β-glucan is accessible to Dectin-1 only during the process of cell budding. Dectin-1 does not recognize the filamentous form of yeast (8). Dectin-1 mediates the phagocytosis of zymosan particles and intact yeast (8-10). In the membrane, Dectin-1 colocalizes with TLR2 in the presence of zymosan, and the two receptors cooperate in ligand recognition and the propagation of proinflammatory signaling (9,11-13). Dectin-1 also interacts with tetraspanin CD37. This increases its stability on the cell membrane and inhibits ligand-induced signaling (14). Dectin-1 knockout mice show increased susceptibility to pathogenic infection (15-16). The CRD of human Dectin-1 shares 77%, 60%, and 60% aa sequence identity with that of bovine, mouse and rat Dectin-1, respectively. It shares 29%-39% aa sequence identity with the CRD of other subgroup members, including CLEC-1, CLEC-2, CLEC9A, CLEC12B, LOX-1, and MICL.
Source:Human CD33 signal peptide (Met 1-Ala 16) HHHHHHHHHH Human Dectin-1 (Thr 66-Met 201). A DNA sequence encoding the extracellular domain of human Dectin-1 (amino acid residues 66-201; Accession # NP_072092) was fused to the signal peptide of human CD33 and a 10X histidine tag at the N-terminus. The protein was expressed in a mouse myeloma cell line, NS0.
Molecular Mass:The recombinant human Dectin-1, generated by the removal of the signal peptide region, is a monomeric protein. Based on N-terminal sequencing, the protein begins with the 10X histidine tag and has a calculated molecular mass of approximately 16.8 kD.
Endotoxin Level:< 0.1 EU per 1 μg of the protein as determined by the LAL method.
Activity:Measured by its ability to bind biotinylated laminarin (1, 3-β-glucan) with an estimated KD < 5nM.
Reconstitution:It is recommended that sterile phosphate-buffered saline be added to the vial to prepare a working stock solution of no less than 100ug/ml. The carrier-free protein should be used immediately upon reconstitution to avoid losses in activity due to non-specific binding to the inside surface of the vial. For long term storage as a dilute solution, a carrier protein (e.g. 0.1% HSA or BSA) should be added to the vial.
Storage and Stability:Lyophilized samples are stable for up to twelve months at -20°C. Upon reconstitution, this protein, in the presence of a carrier protein, can be stored under sterile conditions at 2-8°C for one month or at -20°C in a manual defrost freezer for three months without detectable loss of activity. Avoid repeated freeze-thaw cycles.
