Linked Life Data

1377218

Source:http://linkedlifedata.com/resource/pubmed/id/1377218

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1992-7-28
pubmed:abstractText
The human C1q receptor (C1q-R) is a 65-70-kd, highly acidic, hydrophobic glycoprotein that is expressed on a wide variety of cell surfaces. Although the C1q-R itself appears to bind preferentially to C1q, the region of the ligand to which C1q-R binds is the primary binding site for several other molecules, including fibronectin, laminin, and C1q inhibitor (chondroitin 4-sulfate proteoglycan) as well as the complement C1r2C1s2 tetramer. In order to further characterize the C1q-R molecule with regard to its structure and function, highly purified C1q-R was obtained from Raji cells using DEAE-Sephacel and C1q-Sepharose CL-4B chromatography. Studies performed with 125I-labeled C1q-R demonstrated that whereas the C1q-R molecule binds poorly to a variety of human collagens including types II, III, and V, markedly enhanced binding is observed with type IV collagen and moderately enhanced binding with type I collagen. Amino acid composition studies show that the C1q-R molecule contains approximately 44% hydrophobic and 12.6% hydrophilic residues with a ratio of negatively charged to positively charged residues of about 2:1. Treatment of 125I-labeled C1q-R with endoglycosidase F lowers the apparent molecular size from 70 to 58 kd, whereas endoglycosidase H lowered the size to 64 kd. Treatment with neuraminidase, on the other hand, shifted the size of C1q-R to 60 kd. These results suggest the presence of several highly sialylated complex-type or high mannose-type N-linked oligosaccharide side chains. Because purified C1q-R has a blocked amino terminus, amino acid sequences representing internal fragments of the molecule were generated by electroblotting and in situ enzymatic digestion. When these short sequences were searched against the National Biomedical Research Foundation computer data base, a seven-amino-acid sequence, VSWQGQI, showed significant homology (100% and 80% in a five-amino-acid overlap, respectively) with the alpha chains of the human fibronectin (alpha 5 beta 1) and vitronectin (alpha v beta 3) receptors, and to a lesser degree with epidermal growth factor receptor and T cell receptor. A second sequence, ISEDNIR, showed homology with mouse collagen type IV (86% in a six-amino-acid overlap), calmodulin (60% in a seven-amino-acid overlap), and a Leishmania major surface antigen, gp63. These observations seem to predict that C1q-R has pockets of conserved sequences that are similar to those not only present in its ligand(s) but also in other cell surface receptors that may, in part, fulfill similar functions.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
http://linkedlifedata.com/resource/pubmed/chemical/Amino Acids, http://linkedlifedata.com/resource/pubmed/chemical/Antigens, CD44, http://linkedlifedata.com/resource/pubmed/chemical/C1QBP protein, human, http://linkedlifedata.com/resource/pubmed/chemical/C1qbp protein, mouse, http://linkedlifedata.com/resource/pubmed/chemical/Carrier Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Collagen, http://linkedlifedata.com/resource/pubmed/chemical/Complement Activating Enzymes, http://linkedlifedata.com/resource/pubmed/chemical/Fibronectins, http://linkedlifedata.com/resource/pubmed/chemical/Integrins, http://linkedlifedata.com/resource/pubmed/chemical/Membrane Glycoproteins, http://linkedlifedata.com/resource/pubmed/chemical/Mitochondrial Proteins, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Complement, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Fibronectin, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Immunologic, http://linkedlifedata.com/resource/pubmed/chemical/Receptors, Vitronectin, http://linkedlifedata.com/resource/pubmed/chemical/complement 1q receptor
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0741-5400
pubmed:author
pubmed:issnType
Print
pubmed:volume
51
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
546-56
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Short amino acid sequences derived from C1q receptor (C1q-R) show homology with the alpha chains of fibronectin and vitronectin receptors and collagen type IV.
pubmed:affiliation
Department of Medicine, State University of New York, Stony Brook.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't