Dectin-1, also known as CLEC7A and the β-glucan receptor, is a 43kD type II transmembrane C-type lectin that functions in the innate immune response to fungal pathogens. Although Dectin-1 resembles other CLEC molecules structurally, it binds ligands in a calcium-independent manner (1, 2). Mature mouse Dectin-1 is a 244 aa glycoprotein that consists of a short ITAM-containing cytoplasmic tail, a transmembrane segment, and a stalk and carbohydrate recognition domain (CRD) in the extracellular domain (3). The CRD of mouse Dectin-1 shares 61%, 60%, and 87% aa sequence identity with that of bovine, human, and rat Dectin-1, respectively. It shares 25%-34% aa sequence identity with the CRD of other subgroup members CLEC-1, CLEC-2, CLEC9A, CLEC12B, LOX-1, and MICL. Mouse Dectin-1 is alternately spliced, generating a variant that lacks the stalk region (4). Mouse Dectin-1 is expressed on monocytes, macrophages, and neutrophils, and on some populations of dendritic cells and T cells (5). It is upregulated on macrophages by GM-CSF, IL-4, or IL-13 and downregulated by dexamethasone, IL-10, or LPS (6). The CRD selectively binds β- glucan polymers, a major component of yeast and mycobacterial cell walls (7). Yeast β-glucan is accessible to Dectin-1 only at sites of cell budding, and Dectin-1 does not recognize the filamentous form of yeast (8). Dectin-1 mediates the phagocytosis of zymosan particles and intact yeast (8-10). It 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 interaction with the tetraspanin CD37 increases its stability on the cell membrane and inhibits ligand-induced signaling (14). Genetic knockout of Dectin-1 in mice increases their susceptibility to pathogenic infection (15, 16).
Source:Human CD33 signal peptide, (Met 1-Ala 16), HHHHHHHHHH, Mouse Dectin-1 (Phe 69-Leu 244). A DNA sequence encoding the extracellular domain of mouse Dectin-1 (Phe 69-Leu 244; Genbank Accession # NP_064392) 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:Based on N-terminal sequencing, the recombinant mouse Dectin-1, generated by the removal of the signal peptide, starts at the histidine tag and has a predicted molecular mass of 21.6 kD. As a result of glycosylation the recombinant mouse Dectin-1 migrates as an approximately 27-37kD protein in SDS-PAGE under reducing conditions.
Endotoxin Level:< 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 < 6nM.
Reconstitution:It is recommended that sterile PBS 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.
