Recombinant Human VSIG4 Fc Chimera Avi-tag Protein, CF

When Human iC3b is immobilized at 2.5 μg/mL (100 μL/well), the concentration of Biotinylated Recombinant Human VSIG4 Fc Chimera Avi-tag (AVI4646) that produces 50% optimal binding response is found to be approximately 5-40 ng/mL.

2 μg/lane of Biotinylated Recombinant Human VSIG4 Fc Chimera Avi-tag (Catalog # AVI4646) was resolved with SDS-PAGE under reducing (R) and non-reducing (NR) conditions and visualized by Coomassie® Blue staining, showing bands at kDa.

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

Recombinant Human VSIG4 Fc Chimera Avi-tag Protein, CF Summary

• Additional Information: Biotinylated
• Details of Functionality: The biotin to protein ratio is greater than 0.7 as determined by the HABA assay. Measured by its binding ability in a functional ELISA. When Human iC3b is Immobilized at 2.5 μg/mL (100 μL/well), the concentration of Biotinylated Recombinant Human VSIG4 Fc Chimera Avi‑tag (AVI4646) that produces 50% optimal binding response is found to be approximately 5-40 ng/mL.
• Source: Human embryonic kidney cell, HEK293-derived human VSIG4 protein
  

  Human VSIG4 (Arg20-Pro283) Accession # Q9Y279.1	IEGRMD	Human IgG1 (Pro100-Lys330)	Avi-tag

• Accession #: Q9Y279.1
• N-terminal Sequence: Arg20
• Structure / Form: Disulfide-linked homodimer, biotinylated via Avi-tag
• Protein/Peptide Type: Recombinant Proteins
• 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
  • Bioactivity2
• Theoretical MW: 58 kDa.
  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: 65-85 kDa, under 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 with Trehalose.
• Purity: >95%, by SDS-PAGE visualized with Silver Staining and quantitative densitometry by Coomassie® Blue Staining.
• Reconstitution Instructions: Reconstitute at 200 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 Fc Chimera Avi-tag 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

V-set and immunoglobulin domain containing 4 (VSIG4), also known as CRIg and Z39IG, is a type I transmembrane protein of the B7 family and complement receptor of the immunoglobulin superfamily. Human VSIG4 consists of an extracellular domain (ECD) containing a V-type and a C2-type Ig domain, a transmembrane domain and a cytoplasmic domain (3). Interestingly, VISG4 in several animals, including mouse and rat, lack the C2-type Ig domain present in human VSIG4. Within the IgV domain, mature human VSIG4 shares 80% and 78% amino acid identity with mouse and rat VSIG4, respectively. Alternative splicing results in numerous isoforms lacking all or part of the cytoplasmic domain, the C2-type Ig domain and/or the transmembrane domain. 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 (1-8). 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, 5). It contributes significantly to innate immunity by binding and phagocytosis of complement-opsonized invading pathogens (4, 7, 9). Binding of either native or recombinant soluble VSIG4 to C3b inhibits complement amplification through the alternative, but not classical, pathway (9, 10). 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, 6, 9, 10). VSIG4 expression has been implicated in lung cancer development and associated with poor prognosis of high grade glioma (11, 12). Our Avi-tag Biotinylated Recombinant VSIG4 features biotinylation at a single site contained within the Avi-tag, a unique 15 amino acid peptide. Protein orientation will be uniform when bound to streptavidin-coated surface due to the precise control of biotinylation and the rest of the protein is unchanged so there is no interference in the protein's bioactivity.

1. 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. Tanaka, M. et al. (2008) Clin. Exp. Immunol. 154:38.
6. Lee, M-Y. et al. (2006) J. Leukoc. Biol. 80:922.
7. Gorgani, N.N. et al. (2008) J. Immunol. 181:7902.
8. Walker, M.G. (2002) Biochim. Biophys. Acta 1574:387.
9. Wiesmann, C. et al. (2006) Nature 444:217.
10. Katschke, K.J. et al. (2007) J. Exp. Med. 204:1319.

Bioinformatics

• Uniprot:
  • Q9Y279.1()