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Name :
Human CD22 Protein, ECD (Extracellular Domain), Recombinant

Description :
CD22 is a 130-140 kDa, single-pass type I transmembrane protein belonging to the immunoglobulin superfamily (IgSF) and sialic acid binding Ig-like lectin (SIGLEC) family. CD22 or SIGLEC2 contains 1 Ig-like V-type and 6 Ig-like C2-type domain in the extracellular region that specifically interacts with ligands carrying α2-6-linked sialic acids. Alternate splicing generates an additional isoform that lacks the 3rd and 4th Ig-like domains. CD22 is expressed on B cells and capable of modulating B cell antigen receptor (BCR)-mediated signals, as well as the generation of BCR-independent signals. CD22 is an inhibitory co-receptor of BCR and plays a critical role in establishing signalling thresholds for B-cell activation. CD22 has 3 immunoreceptor tyrosine-based inhibitory motifs (ITIMs) in its cytoplasmic region that recruits the tyrosine phosphatase Src homology 2 domain-containing phosphatase 1 (SHP-1) to ITIMs and inhibits BCR-induced Ca2+ signaling in B cells. Phosphorylation of Tyr822 within one of ITIMs is important for CD22 signal transduction through its association with the kinases Lyn, PI3-Kinase p85α, and SYK. Interaction of CD22 to ligands in trans can regulate B-cell migration as well as the BCR signaling threshold. A more complex role for CD22 has recently been described including a role in a regulatory loop that mediates basal signaling thresholds and Src-family protein tyrosine kinase (PTK) amplification after BCR ligation. CD19 regulates CD22 phosphorylation by augmenting Lyn kinase activity, while CD22 inhibits CD19 phosphorylation via SHP-1.

Gene Symbol :

NCBI Gene ID :

Uniprot Entry :

Construct Details :
The recombinant human CD22 ECD is expressed as a 675 amino acid protein consisting of Asp20 – Thr683 region of CD22 (UniProt accession #P20273) and a C-terminal His-tag. It contains 12 potential sites for N-linked glycosylation.

Source :
Human cells stably expressing human CD22 ECD and growing in chemical-defined media with no animal components or antibiotics

Amino Acid Sequence: :

M.W. :
Calculated molecular mass (kDa): 76.0; Estimated by SDS-PAGE under reducing condition (kDa): 100-110 probably due to glycosylation

Calculated PI :

Calculated Extinction Coefficients :
(M-1 cm-1, at 280nm): 145395

Endotoxin Level :
>90% judged by SDS-PAGE under reducing condition (see the gel image above, labeled as “S” and “M” for marker)

Formulation :
Supplied at 0.5 mg/ml in sterile PBS pH7.4 (carrier & preservative free).

Endotoxin Level :
<0.1 EU per 1 μg of purified recombinant protein determined by the LAL method

Biological Activity :
Immobilized CD22 ECD protein supports the adhesion of human red blood cells. Binds anti-CD22 monoclonal antibodies (SKU#MAB1175, SKU#MAB1195) with high affinity (KD

Molecule Class :
1-Pass Type I Transmembrane

Gene Synonym :
<0.1 EU per 1 μg of purified recombinant protein determined by the LAL method

Gene Family :

Research Area :

Pathway/Disease :
B Cell Development

Species :

CD Antigen :

References :
1. Nature 345:74-77(1990) 2. J. Exp. Med. 173:137-146(1991) 3. Science 269:242-244(1995) 4. Annu. Rev. Immunol. 15:481-504(1997) 5. Immunol Rev. 230: 128-43 (2009)

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