Recombinant Human VSIG4 (aa 20-283) Fc Chimera Protein, CF

• Reactivity: Hu
• Applications: Bioactivity
• Format: Carrier-Free

Recombinant Human VSIG4 (aa 20-283) Fc Chimera Protein, CF Summary

• Details of Functionality: Measured by its binding ability in a functional ELISA. Immobilized Recombinant Human VSIG4 Fc Chimera at 5 µg/mL (100 µL/well) can bind complement component iC3b with an apparent K_d <20 nM.
• Source: Mouse myeloma cell line, NS0-derived human VSIG4 protein
  

  Human VSIG4 (Arg20-Pro283) Accession # Q9Y279	IEGRMD	Human IgG1 (Pro100-Lys330)
  N-terminus		C-terminus

• Accession #: Q9Y279
• N-terminal Sequence: Arg20
• Structure / Form: Disulfide-linked homodimer
• Protein/Peptide Type: Recombinant Proteins
• Gene: VSIG4
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
• Endotoxin Note: <0.10 EU per 1 μg of the protein by the LAL method.

Applications/Dilutions

• Dilutions:
  • Bioactivity
• Theoretical MW: 55.8 kDa (monomer).
  Disclaimer note: The observed molecular weight of the protein may vary from the listed predicted molecular weight due to post translational modifications, post translation cleavages, relative charges, and other experimental factors.
• SDS-PAGE: 60-70 kDa, reducing conditions

Packaging, Storage & Formulations

• Storage: Use a manual defrost freezer and avoid repeated freeze-thaw cycles.
  • 12 months from date of receipt, -20 to -70 °C as supplied.
  • 1 month, 2 to 8 °C under sterile conditions after reconstitution.
  • 3 months, -20 to -70 °C under sterile conditions after reconstitution.
• Buffer: Lyophilized from a 0.2 μm filtered solution in PBS.
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
• Reconstitution Instructions: Reconstitute at 500 μg/mL in PBS.

Notes

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

Alternate Names for Recombinant Human VSIG4 (aa 20-283) Fc Chimera Protein, CF

• CRIg
• Ig superfamily protein
• Protein Z39Ig
• V-set and immunoglobulin domain containing 4
• V-set and immunoglobulin domain-containing protein 4
• VSIG4
• Z39IG
• Z39IGcomplement receptor of the immunoglobulin superfamily

Background

VSIG4 (V-set and immunoglobulin domain containing 4), also known as CRIg and Z39IG, is a 45 kDa, type I transmembrane protein of the B7 family within the Ig superfamily that is expressed only in tissue-resident macrophages (1-4). The gene is located on the X chromosome (2). The human VSIG4 cDNA encodes 399 amino acids (aa) including a 19 aa signal sequence, a 264 aa extracellular domain (ECD) containing a V-type and a C2-type Ig domain, a 21 aa transmembrane domain and a 95 aa cytoplasmic domain (3). The human VSIG4 ECD shares 84% aa identity with canine VSIG4. Within the IgV domain, it shares 90%, 80% and 78% aa identity with bovine, mouse and rat VSIG4, respectively; these animals lack the C2-type domain. Splice isoforms of 321, 305, 272, 201 and 199 aa lack all or part of the cytoplasmic domain, the C2-type Ig domain and/or the transmembrane domain (5). VSIG4 is specifically expressed on macrophages in the thymic medulla, peritoneum, alveoli, synovia, adipose and heart, liver Kupffer cells, placental Hofbauer cells, and atherosclerotic foam cells (1-4, 6-9). It is absent on infiltrating macrophages (8). VSIG4 is a complement receptor that binds C3b and iC3b fragments, internalizes them to recycling endosomes, and is recycled to the cell surface (4, 6). It contributes significantly to innate immunity by binding and phagocytosis of complement-opsonized invading pathogens (4, 8, 10). Binding of either native or recombinant soluble VSIG4 to C3b inhibits complement amplification through the alternative, but not classical, pathway (10, 11). VSIG4 is also a negative regulator of mouse and human T cell activation (2). Although VSIG4 engagement may activate NF kappa B and thus be pro-inflammatory in some cases, many of its activities are important in resolving, rather than initiating, inflammation (1, 2, 7, 10, 11).

1. He, J.Q. et al. (2008) Mol. Immunol. 4041.
2. Vogt, L. et al. (2006) J. Clin. Invest. 116:2817.
3. Langnaese, K. et al. (2000) Biochim. Biophys. Acta 1492:522.
4. Helmy, K. et al. (2006) Cell 124:915.
5. Entrez protein Accession # EAX05393, NP_001093901, CAI42052, CAI4205, EAX05394.
6. Tanaka, M. et al. (2008) Clin. Exp. Immunol. 154:38.
7. Lee, M-Y. et al. (2006) J. Leukoc. Biol. 80:922.
8. Gorgani, N.N. et al. (2008) J. Immunol. 181:7902.
9. Walker, M.G. (2002) Biochim. Biophys. Acta 1574:387.
10. Wiesmann, C. et al. (2006) Nature 444:217.
11. Katschke, K.J. et al. (2007) J. Exp. Med. 204:1319.

Bioinformatics

• Gene Symbol: VSIG4
• Uniprot:
  • Q9Y279()