Human Siglec-2 / CD22 Protein (aa 176-687, His Tag)

SIGLEC-2,SIGLEC2

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Catalog Number	P11958-H08H1
Organism Species	Human
Host	Human Cells
Synonyms	SIGLEC-2,SIGLEC2
Molecular Weight	The recombinant human CD22 consists of 523 amino acids and predictes a molecular mass of 58.5 kDa. In SDS-PAGE under reducing conditions, the apparent molecular mass of the recombinant protein is approximately 90-100 kDa due to glycosylation.
predicted N	Trp 176
SDS-PAGE
Purity	> 90 % as determined by SDS-PAGE
Protein Construction	A DNA sequence encoding the human CD22 (Q32M46) (Trp176-Arg687) was fused with a polyhistidine tag at the C-terminus.
Bio-activity
Research Area	Immunology |Signal Transduction |ITIM/ITAM Immunoreceptors and Related Molecules
Formulation	Lyophilized from sterile PBS, pH 7.4. 1. Normally 5 % - 8 % trehalose, mannitol and 0.01% Tween80 are added as protectants before lyophilization. Specific concentrations are included in the hardcopy of COA.
Background	CD22 is a member of the immunoglobulin superfamily, SIGLEC family of lectins. It is first expressed in the cytoplasm of pro-B and pre-B cells, and on the surface as B cells mature to become IgD+. CD22 serves as an adhesion receptor for sialic acid-bearing ligands expressed on erythrocytes and all leukocyte classes. In addition to its potential role as a mediator of intercellular interactions, signal transduction through CD22 can activate B cells and modulate antigen receptor signaling in vitro. The phenotype of CD22-deficient mice suggests that CD22 is primarily involved in the generation of mature B cells within the bone marrow, blood, and marginal zones of lymphoid tissues. CD22 recruits the tyrosine phosphatase Src homology 2 domain-containing phosphatase 1 (SHP-1) to immunoreceptor tyrosine-based inhibitory motifs (ITIMs) and inhibits B-cell receptor (BCR)-induced Ca2+ signaling on normal B cells. CD22 interacts specifically with ligands carrying alpha2-6-linked sialic acids. As an inhibitory coreceptor of the B-cell receptor (BCR), CD22 plays a critical role in establishing signalling thresholds for B-cell activation. Like other coreceptors, the ability of CD22 to modulate B-cell signalling is critically dependent upon its proximity to the BCR, and this in turn is governed by the binding of its extracellular domain to alpha2,6-linked sialic acid ligands. However, genetic studies in mice reveal that some CD22 functions are regulated by ligand binding, whereas other functions are ligand-independent and may only require expression of an intact CD22 cytoplasmic domain at the B-cell surface. CD19 regulates CD22 phosphorylation by augmenting Lyn kinase activity, while CD22 inhibits CD19 phosphorylation via SHP-1.
Reference	Tedder TF, et al. (1997) CD22, a B lymphocyte-specific adhesion molecule that regulates antigen receptor signaling. Annu Rev Immunol. 15: 481-504. Tedder TF, et al. (2005) CD22: a multifunctional receptor that regulates B lymphocyte survival and signal transduction. Adv Immunol. 88: 1-50. Fujimoto M, et al. (2007) B cell signaling and autoimmune diseases: CD19/CD22 loop as a B cell signaling device to regulate the balance of autoimmunity. J Dermatol Sci. 46(1): 1-9. Walker JA, et al. (2008) CD22: an inhibitory enigma. Immunology. 123(3): 314-25. Nitschke L. (2009) CD22 and Siglec-G: B-cell inhibitory receptors with distinct functions. Immunol Rev. 230(1): 128-43.