Recombinant Mouse FCRN Heterodimer Protein, CF

Recombinant Mouse FCRN (Catalog # 9114-FC) has a molecular weight (MW) of 49.4 kDa as analyzed by SEC-MALS, suggesting that this protein is a heterodimer. MW may differ from predicted MW due to post-translational modifications (PTMs) present (i.e. Glycosylation).

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

Recombinant Mouse FCRN Heterodimer Protein, CF Summary

• Additional Information: Analyzed by SEC-MALS. Non-covalently associated with endogenous beta 2-Microglobulin
• Details of Functionality: Measured by its binding ability in a functional ELISA. When Recombinant Mouse FCRN is immobilized at 0.5 μg/mL (100 μL/well), the concentration of human IgG that produces 50% of the optimal binding response is found to be approximately 2-10 μg/mL.
• Source: Mouse myeloma cell line, NS0-derived mouse FCRN protein
  Ser22-Ser301 with a C-terminal 6-His tag
• Accession #: Q6PKB0
• N-terminal Sequence: Ser22 (FcRN) & Ile21 ( beta -2-microglobulin)
• Structure / Form: Non-covalently linked heterodimer with endogenous mouse beta -2-microglobulin from NS0 cells.
• Protein/Peptide Type: Recombinant Proteins
• Gene: Fcgrt
• 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: 32 kDa (mFcRN); 12 kDa (m beta -2-microglobulin).
  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: 41-46 kDa (mFcRN); 9 - 12 kDa (m beta -2-microglobulin)

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 250 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 Mouse FCRN Heterodimer Protein, CF

• alpha-chain
• Fc fragment of IgG, receptor, transporter, alpha
• FCGRT
• FcRn alpha chain
• FCRN
• FCRNimmunoglobulin receptor, intestinal, heavy chain
• IgG Fc fragment receptor transporter alpha chain
• IgG receptor FcRn large subunit p51
• major histocompatibility complex class I-like Fc receptor
• Neonatal Fc receptor
• neonatal Fc-receptor for Ig

Background

The neonatal Fc receptor (FcRN) is an approximately 45 kDa transmembrane glycoprotein with structural homology to MHC class I proteins. It is widely expressed in endothelial and epithelial cells and plays an important role in IgG homeostasis (1, 2). Mature mouse FcRN consists of a 276 amino acid (aa) extracellular domain (ECD) with two N-terminal alpha domains, one a3/immunoglobulin-like domain, a 24 aa transmembrane segment, and a 44 aa cytoplasmic domain (3). Within the ECD, mouse FcRN shares 69% and 91% aa sequence identity with human and rat FcRN, respectively. Mouse FcRN binds with high affinity to IgG from mouse, human, rat, rabbit, guinea pig, bovine, and sheep, while human FcRN binds IgG with significantly lower affinity and is much more restricted in terms of species recognition (4). It does not bind the structurally related chicken IgY (5). FcRN additionally binds to albumin, and both it and IgG are bound at pH 5.0 but not at pH 8.0 (3, 6). FcRN associates noncovalently with beta 2-Microglobulin, and this interaction is important for the intracellular trafficking of FcRN (7-10). FcRN cycles between the plasma membrane and acidified intracellular compartments of endothelial cells and epithelial cells (5, 8). It binds endocytosed IgG and albumin in the low pH vesicles and transports them to the plasma membrane for extracellular release at higher pH. This protects IgG and albumin from lysosomal degradation and helps maintain the circulating levels of both proteins (5, 6). This mechanism is involved in the bidirectional transport of IgG across epithelial and endothelial barriers including neonatal IgG absorption in the intestine and fetal uptake of maternal antibodies through the placenta (5, 8, 11, 12). In the kidney, FcRN recycles albumin to the serum but removes IgG from the glomular basement membrane and promotes its excretion into the urine (13, 14). FcRN is also expressed in neutrophils and myeloid antigen presenting cells (7, 15, 16). It can enhance IgG-mediated phagocytosis and antigen presentation by these cells, but it promotes the degradation of opsonizing IgG rather than returning it to the circulation (15, 16).

1. Stapleton, N.M. et al. (2015) Immunol. Rev. 268:253.
2. Pyzik, M. et al. (2015) J. Immunol. 194:4595.
3. Ahouse, J.J. et al. (1993) J. Immunol. 151:6076.
4. Ober, R.J. et al. (2001) Int. Immunol. 13:1551.
5. Dickinson, B.L. et al. (1999) J. Clin. Invest. 104:903.
6. Chaudhury, C. et al. (2003) J. Exp. Med. 197:315.
7. Simister, N.E. and K.E. Mostov (1989) Nature 337:184.
8. Kobayashi, N. et al. (2002) Am. J. Physiol. Renal Physiol. 282:F358.
9. Praetor, A. and W. Hunziker (2002) J. Cell Sci. 115:2389.
10. Zhu, X. et al. (2001) J. Immunol. 166:3266.
11. Spiekermann, G.M. et al. (2002) J. Exp. Med. 1. Stapleton, N.M. et al. (2015) Immunol. Rev. 268:253.
    
12. Firan, M. et al. (2001) Int. Immunol. 13:993.
    
13. Sarav, M. et al. (2009) J. Am. Soc. Nephrol. 20:1941.
    
14. Akilesh, S. et al. (2008) Proc. Natl. Acad. Sci. 105:967.
    
15. Vidarsson, G. et al. (2006) Blood 108:3573.
16. Qiao, S.-W. et al. (2008) Proc. Natl. Acad. Sci. 105:9337.

Bioinformatics

• Gene Symbol: Fcgrt
• Uniprot:
  • Q6PKB0()