These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Structure and function of gC1q-R: a multiligand binding cellular protein.
    Author: Ghebrehiwet B, Peerschke EI.
    Journal: Immunobiology; 1998 Aug; 199(2):225-38. PubMed ID: 9777408.
    Abstract:
    gC1q-R is a 33 kDa, single chain, highly acidic protein, which was first isolated from membrane preparation of Raji cells and now appears to be ubiquitously distributed. Although, gC1q-R was originally identified as a protein which binds to the globular "heads" of C1q, recent evidence suggests that the molecule is in fact a multiligand binding, multifunctional protein with affinity for diverse ligands which at best are functionally related. These molecules include: thrombin, vitronectin, and high molecular weight kininogen. The gC1q-R molecule, which is identical to the transcription factors SF2 and the Tat-associated protein, or TAP, is the product of a single gene localized on chromosome 17p13.3 in human, and chromosome 11 in mouse, and is encoded by an approximately 1.5-1.6 kb mRNA. The full length cDNA encodes a primary translation protein of 282 residues and the 'mature' or membrane form of the protein isolated from Raji cells corresponds to residues 74-282 and is presumed to be generated by a site-specific cleavage and removal of the highly basic, 73-residues long, N-terminal segment during post-translational processing. The translated amino acid sequence does not predict for the presence of a conventional sequence motif compatible with a transmembrane segment and does not have a consensus site for a GPI anchor. However, there is strong evidence which indicates that gC1q-R is expressed both inside the cell and on the membrane. First, certain mAbs raised against gC1q-R react moderately with intact Raji cells in suspension and this binding increases when the cells are first bound to poly-L-lysine coated surfaces and then fixed with glutaraldehyde. Second, surface labeling of cells using the membrane impermeable sulfo-NHS-LC-biotin shows that gC1q-R on the surface incorporates biotin whereas intracellular gC1q-R does not. In addition, the membrane expression of gC1q-R can be upregulated with inflammatory cytokines such as INF-gamma, TNF-alpha, or LPS. These results suggest, that gC1q-R, is localized both as an intracellular and as a cell surface protein and may have important biological functions in both compartments of the cell.
    [Abstract] [Full Text] [Related] [New Search]