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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
15
pubmed:dateCreated
2006-4-11
pubmed:abstractText
We used laser tweezers-based force spectroscopy to measure the binding strength between fibrinogen molecules covalently bound to latex beads and either wild-type alphaIIbbeta3 molecules or alphaIIbbeta3 molecules containing the transmembrane domain mutations beta3 G708N or alphaIIb G972N expressed on Chinese hamster ovary cells. As we demonstrated previously for alphaIIbbeta3 on agonist-stimulated platelets and for purified alphaIIbbeta3 molecules incubated with Mn(2+), two regimes of rupture forces were present when wild-type alphaIIbbeta3 was activated by the monoclonal antibody PT25-2: rupture forces of 20-60 pN with an exponentially decreasing probability of detection and rupture forces in the range of 60-150 pN with a maximum at approximately 70-80 pN. Both rupture force regimes were specific for fibrinogen binding to the activated conformation of alphaIIbbeta3 because they were inhibited by alphaIIbbeta3-specific antagonists. Identical rupture force regimes were present constitutively when cells expressing the alphaIIb and beta3 transmembrane domain mutants were studied, confirming that these mutations induced an active alphaIIbbeta3 conformation. Moreover, there were no significant differences in the yield strength of the low-to-moderate and strong force regimes when alphaIIbbeta3 was activated by PT25-2 or the transmembrane domain mutations, implying that there was no fundamental difference in the way these forms of activated alphaIIbbeta3 interacted with fibrinogen. Thus, the two-step pathway of the interaction of alphaIIbbeta3 with fibrinogen we have identified appears to be a fundamental property of the high-affinity state of alphaIIbbeta3 and is identical regardless of whether this affinity state is achieved by intracellular, extracellular, or membrane-associated events.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Apr
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
45
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
4957-64
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed:year
2006
pubmed:articleTitle
Activation of individual alphaIIbbeta3 integrin molecules by disruption of transmembrane domain interactions in the absence of clustering.
pubmed:affiliation
Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104, USA.
pubmed:publicationType
Journal Article, Comparative Study, Research Support, N.I.H., Extramural