C1q Receptor, gamma (gC1qR, C1qBP, Complement Component 1, Q Subcomponent-binding Protein)

This monoclonal antibody recognizes a cell membrane C1q binding molecule that recognises the globular heads of C1q. It is also present in plasma and the extracellular matrix. The molecule is an unusually acidic, single chain protein with an apparent molecular weight of 33kD. It does not possess a conventional sequence motif compatible with a membrane spanning segment nor a consensus site for a GPI anchor. gC1q-R migrates as a single chain under both reducing and non-reducing conditions, but it behaves as an oligomer on gel-filtration in non-dissociating conditions. Its multimer formation may be a critical process by which the gC1q-R molecule increases its affinity for multivalent ligands such as C1q. gC1q-R has been shown to inhibit complement activation by preventing the binding of C1q to antibodies, suggesting that the binding site for gC1q-R and the binding site for immune complexes, which are present on the C1q globular 'heads', may be located at the same position. gC1q-R is capable of interacting with several proteins involved in blood clotting, namely, thrombin, prothrombin, the heparinbinding form of vitronectin, the ternary complex, vitronectin-thrombin-antithrombin, as well as high-molecular-weight kininogen and Hageman factor. Besides its role in the complement pathway, gC1q-R participates in enhancement of Fc-receptor and CR1-mediated phagocytosis, procoagulant activity on platelets, and chemotactic activity on mast cells, eosinophils, neutrophils, and fibroblasts. gC1q-R is expressed on a wide variety of cells and can serve as a binding site for plasma and microbial proteins. Its antigenic sites may be cryptic on cells in suspension but become exposed when the cells are fixed by bifunctional cross-linkers. Probably it is also expressed on the cell membrane as a tetramer. Crosslinking or activation may thus bring about a tetrameric assembly of gC1q-R followed by a conformational change within the molecule, thereby exposing epitopes which are otherwise hidden. A form of GC1q-R is also found inside the cell. Intracellular gC1q-R has been shown to bind the cytoplasmic tail of the a1B-adrenergic receptor and to PKCu.\n\nApplications:\nSuitable for use in Western Blot, Flow Cytometry, Functional Studies, ELISA and Immunoprecipitation. Other applications not tested.\n\nRecommended Dilution:\nFlow Cytometry: 1:50\nOptimal dilutions to be determined by the researcher.\n\nStorage and Stability:\nMay be stored at 4 degrees C for short-term only. Aliquot to avoid repeated freezing and thawing. Store at -20 degrees C. Aliquots are stable for at least 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap.

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SPECIFICATIONS

Catalog Number

C0010-12A

Size

100ug

Applications

ELISA, FC, IP, WB

Hosts

Mouse

Reactivities

Hum, Rat

Form

Supplied as a liquid in PBS, 0.1% BSA.

P Type

Mab

Purity

Purified by Protein G affinity chromatography.

Isotype

IgG1

References

1. Ghebrehiwet, B et al; Identification of functional domains on gC1Q-R, a cell surface protein that binds to the globular \"heads\" of C1Q, using monoclonal antibodies and synthetic peptides. Hybridoma 1996, 5: 333. 2. Ghebrehiwet, B et al; Evidence that the two C1q binding membrane proteins, gC1q-R and cC1q-R, associate to form a complex. J Immunol 1997, 159: 1429. 3. Ghebrehiwet, B et al; gC1q-R/p33, a member of a new class of multifunctional and multicompartmental cellular proteins, is involved in inflammation and infection. Immunol Rev 2001, 180: 65. 4. Grace, K et al; Surface expression of complement receptor gC1q-R/p33 is increased on the plasma membrane of human spermatozoa after capacitation. Biol Reprod 2002, 66: 823. 5. Peerschke, E et al; gC1qR/p33 blockade reduces Staphylococcus aureus colonization of target tissues in an animal model of infective endocarditis. Infect Immun 2006, 74: 4418. 6. Sansonno, D et al; Role of the receptor for the globular domain of C1q protein in the pathogenesis of hepatitis C virau-related cryoglobulin vascular damage. J Immunol 2009, 183: 6013.

Additional Info

Recognizes epitopes situated within the NH2-terminal stretch of gC1q-R corresponding to aa76-93. This clone recognizes the putative C1q binding site and reacts with the mature form, but has poor or no reactivity with the truncated form, lacking aa74-95. Species Crossreactivity: rat and syrian hamster.