Recombinant Cynomolgus Siglec-2/CD22 Fc Chimera Protein, CF

This product is produced by and ships from R&D Systems, Inc., a Bio-Techne brand.

Siglecs are sialic acid specific I‑type lectins that are characterized by an extracellular domain (ECD) with an N‑terminal Ig‑like V-type domain followed by varying numbers of Ig‑like C2-type domains (1, 2). Siglec-2, also known as B cell antigen CD22 or B-lymphocyte cell adhesion molecule (BL-CAM), is a B cell restricted glycoprotein that is expressed in the cytoplasm of progenitor B and pre-B cells and on the surface of mature B cells. In humans, two distinct Siglec-2 cDNAs that arise from differential RNA processing of the same gene have been isolated. The predominant Siglec-2 (Isoform CD22-beta) encodes an 847 amino acid (aa) polypeptide with a hydrophobic signal peptide, an N-terminal Ig-like V-type domain, six Ig-like C2-type domains, a transmembrane region and a cytoplasmic tail with four immunoreceptor tyrosine-based inhibition motifs (ITIMs) (3). The variant Siglec-2 (Isoform CD22-alpha) encodes a 647 aa polypeptide missing two Ig-like C2-type domains and has a truncated (23 aa) cytoplasmic tail (4). Within the ECD, cynomolgus Siglec-2 shares 84%, 55%, and 56% aa sequence identity with human, mouse, and rat Siglec-2, respectively. Siglec-2 is an adhesion molecule that preferentially binds alpha 2,6- linked sialic acid on the same (cis) or adjacent (trans) cells. Interaction of Siglec-2 with trans ligands on opposing cells is found to be favored over the binding of ligands in cis (5). Consistent with a single ligand-binding region, the first two N-terminal Ig-like domains mediated CD22 adhesion with lymphocytes, neutrophils, monocytes, and erythrocytes (6). Besides its role as an adhesion molecule, Siglec-2 is a co-receptor that physically interacts with B cell receptor (BCR) and is rapidly phosphorylated upon BCR ligation. It negatively regulates BCR signals by recruiting tyrosine phosphatase SHP-1 to its ITIMs. Phosphorylated Siglec-2 can also interact with other intracellular effector proteins such as Syk, PLC gamma, PI3 kinase and Grb-2, suggesting it may play a role in positive signaling (7, 8).

Array 10031-SL

• Siglec-2/CD22 Antibodies
• Siglec-2/CD22 Protein
• Siglec-2/CD22 ELISA
• Siglec-2/CD22 Proteins and Enzymes