Linked Life Data

8640377

Source:http://linkedlifedata.com/resource/pubmed/id/8640377

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
5
pubmed:dateCreated
1996-7-18
pubmed:abstractText
Integrins exhibit reversible changes in their ability to bind ligands and these changes enable transient cell adhesion. We recently showed that leukocyte integrin CR3 (complement receptor type three, CD11b/CD18, alpha m beta 2) may be purified in a form that is either capable or incapable of binding soluble, monomeric ligand and that "inactive" CR3 may be rendered capable of binding ligand by addition of an anti-CR3 mAb known as KIM-127 (Cai and Wright, JBC. 270: 14358, 1995). Here, we demonstrate that active CR3 may be rendered inactive by treatment of immobilized receptor with EDTA. EDTA-treated CR3 failed to bind ligand even in the presence of mM Ca2+ and Mg2+, suggesting that EDTA-treatment caused a change in the receptor that is not readily reversed. EDTA-treated receptor did, however, bind ligand upon addition of KIM-127 plus Mg2+ with an affinity (17.8 +/- 4.5 nM) similar to untreated, active receptor (12.5 +/- 4.7 nM). EDTA-treated CR3 thus exhibits the properties of inactive CR3, in which the ligand binding site is cryptic but subject to exposure by KIM-127. A candidate for the cryptic ligand binding site is the I-domain, a Mg2+-binding region in the alpha chain of CR3. We found that monomeric C3bi binds directly to recombinant I-domain in a Mg(2+)-dependent fashion with an affinity of 300 +/- 113 nM. These results thus suggest that CR3 may be inactivated by removing tightly bound divalent cation from a cryptic site in CR3.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
1061-5385
pubmed:author
pubmed:issnType
Print
pubmed:volume
3
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
399-406
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1995
pubmed:articleTitle
Reversible inactivation of purified leukocyte integrin CR3 (CD11b/CD18, alpha m beta 2) by removal of divalent cations from a cryptic site.
pubmed:affiliation
Laboratory of Cellular Physiology and Immunology, Rockefeller University, New York, NY 10021, USA.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't