Functional and structural correlations of individual αIIbβ3 molecules

Litvinov, Rustem I.; Nagaswami, Chandrasekaran; Vilaire, Gaston; Shuman, Henry; Bennett, Joel S.; Weisel, John W.

doi:10.1182/blood-2004-04-1411

Cited by 67 publications

(79 citation statements)

References 48 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Unfortunately, as shown above, protein aggregation and particle size heterogeneity were observed, which made it impossible to obtain the configuration of ␣IIb␤3 in solutions with Mn 2ϩ as planned. This observation is in agreement with the earlier chromatographic elution of ␣IIb␤3 in Mn 2ϩ buffer with respect to ␣IIb␤3 in Ca 2ϩ buffer and with previous observations that Mn 2ϩ , but not Ca 2ϩ , can induce formation of dimers and multimers of whole ␣IIb␤3 and r-␣V␤3 (13,33).…”

Section: Reconstruction Of the High Resolution Structural Model Of Whsupporting

confidence: 81%

Three-dimensional Model of Human Platelet Integrin αIIbβ3 in Solution Obtained by Small Angle Neutron Scattering

Nogales

García

Pérez

et al. 2010

Journal of Biological Chemistry

View full text Add to dashboard Cite

Integrin ␣IIb␤3 is the major membrane protein and adhesion receptor at the surface of blood platelets, which after activation plays a key role in platelet plug formation in hemostasis and thrombosis. Small angle neutron scattering (SANS) and shape reconstruction algorithms allowed formation of a low resolution three-dimensional model of whole ␣IIb␤3 in Ca 2؉ /detergent solutions. Model projections after 90°rotation along its long axis show an elongated and "arched" form (135°) not observed before and a "handgun" form. This 20-nm-long structure is well defined, despite ␣IIb␤3 multidomain nature and expected segmental flexibility, with the largest region at the top, followed by two narrower and smaller regions at the bottom. Docking of this SANS envelope into the high resolution structure of ␣IIb␤3, reconstructed from crystallographic and NMR data, shows that the solution structure is less constrained, allows tentative assignment of the disposition of the ␣IIb and ␤3 subunits and their domains within the model, and points out the structural analogies and differences of the SANS model with the crystallographic models of the recombinant ectodomains of ␣IIb␤3 and ␣V␤3 and with the cryo-electron microscopy model of whole ␣IIb␤3. The ectodomain is in the bent configuration at the top of the model, where ␣IIb and ␤3 occupy the concave and convex sides, respectively, at the arched projection, with their bent knees at its apex. It follows the narrower transmembrane region and the cytoplasmic domains at the bottom end. ␣IIb␤3 aggregated in Mn 2؉ /detergent solutions, which impeded to get its SANS model.Blood platelets have distinct mechanisms to respond to the different agonists of platelet activation, all of which end up with the acquisition by the integrin ␣IIb␤3 or glycoprotein IIb/IIIa of the capacity to recognize and bind fibrinogen and other adhesive proteins. Binding of fibrinogen, the major adhesive protein in plasma, to activated ␣IIb␤3 and the binding of fibronectin, the major adhesive protein in the extracellular matrix of subendothelium, to resting or activated ␣IIb␤3 lead to the formation of interplatelet cross-linking and to platelet adhesion to the subendothelium, respectively, and, eventually, to the formation of the platelet plug. Thus, knowledge of the fibrinogen receptor and the mechanisms of induction and modulation of its activity is determinant to understand hemostasis and the pathophysiological paths leading to thrombosis, as well as to develop new ways to prevent, detect, and treat thrombosis effectively, securely, and selectively. After 20 years of molecular genetics and 10 years of high resolution structural biology of integrins, the disposition of an integrin in the membrane is unknown, the modifications in the cytoplasmic domains and the transmembrane segments related with the receptor activation are still not definitively defined, and the molecular mechanism of activation and molecular properties of the activated receptor are still under discussion (1-4). Structural and cell biological informat...

show abstract

Section: Reconstruction Of the High Resolution Structural Model Of Whsupporting

confidence: 81%

Three-dimensional Model of Human Platelet Integrin αIIbβ3 in Solution Obtained by Small Angle Neutron Scattering

Nogales

García

Pérez

et al. 2010

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…Previously, we found that the presence of Mn 2ϩ favored the formation of higher affinity ␣IIb␤3-fibrinogen complexes characterized by a higher binding energy and reduced off-rate (20,21,23). Here, we found that Mn 2ϩ shifts ␣IIb␤3 to a higher activation state by modulating both the on-rate and the rate at which ␣IIb␤3 transitions from a lower to a higher affinity state.…”

Section: Discussionmentioning

confidence: 63%

“…The polypeptide composition, purity, and lack of oligomerization of ␣IIb␤3 and fibrinogen were assessed by SDS-PAGE and by transmission electron microscopy. The binding probability and rupture force profiles ensure single molecule interactions as inferred from the criteria based on previous experiments performed using the same protein binding protocols (12,20,21,23).…”

Section: Methodsmentioning

confidence: 99%

“…These results imply that the surface density of fibrinogen-reactive ␣IIb␤3 molecules and the population of the ␣IIb␤3-fibrinogen complex remained the same before and after treatment with Mn 2ϩ . Because Mn 2ϩ is expected to recruit active ␣IIb␤3 molecules from the available pool (23,28), ␣IIb␤3 should have been present in excess initially compared with fibrinogen.…”

Section: Journal Of Biological Chemistry 35277mentioning

confidence: 99%

See 1 more Smart Citation

Resolving Two-dimensional Kinetics of the Integrin αIIbβ3-Fibrinogen Interactions Using Binding-Unbinding Correlation Spectroscopy

Litvinov

Mekler

Shuman

et al. 2012

Journal of Biological Chemistry

Self Cite

View full text Add to dashboard Cite

Background:The two-dimensional kinetics of receptor-ligand interactions determines cell adherence and release. Results: Based on kinetic parameters, time-and force-dependent transitions of bimolecular integrin ␣IIb␤3-fibrinogen complex were revealed. Conclusion: Coupled force-free binding and forced unbinding kinetics reflects dynamics of surface-attached receptor and ligand molecules. Significance: A new approach to explore the mechanism and kinetics of bimolecular interactions has been proposed.

show abstract

“…Integrin affinity can be uniquely regulated through a process called inside-out signaling, in which stimuli received by other cell surface receptors initiate intracellular signals that impinge on integrin cytoplasmic domains and alter integrin conformation and ligand-binding affinity . In addition, binding of ligand to integrins can trigger the transduction of extracellular signals into the cytoplasm and activate downstream signals in the classic outside-in signaling (Litvinov et al, 2004;Luo et al, 2007). Moreover, lateral assembly of integrins (integrin clustering) is known to augment integrin-mediated adhesion by increasing the bond valency and also contributes to signal transduction (Miyamoto et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Disruption of disulfide-restriction at integrin knees induces activation and ligand-independent signaling of α4β7

Zhang

Pan

et al. 2013

Journal of Cell Science

View full text Add to dashboard Cite

SummaryControl of integrin activation and signaling plays crucial roles in cell adhesion, spreading and migration. Here, we report that selective breakage of two conserved disulfide bonds located at the knees of integrin a 4 C589-C594 and b 7 C494-C526 activated a 4 b 7 . This activated integrin had a unique structure that was different from the typical extended conformation of active integrin. In addition, these activated a 4 b 7 integrins spontaneously clustered on the cell membrane and triggered integrin downstream signaling independent of ligand binding. Although these disulfide bonds were not broken during a 4 b 7 activation by inside-out signaling or Mn 2+ , they could be specifically reduced by 0.1 mM dithiothreitol, a reducing strength that could be produced in vivo under certain conditions. Our findings reveal a novel mechanism of integrin activation under specific reducing conditions by which integrin can signal and promote cell spreading in the absence of ligand.

show abstract

Functional and structural correlations of individual αIIbβ3 molecules

Cited by 67 publications

References 48 publications

Three-dimensional Model of Human Platelet Integrin αIIbβ3 in Solution Obtained by Small Angle Neutron Scattering

Three-dimensional Model of Human Platelet Integrin αIIbβ3 in Solution Obtained by Small Angle Neutron Scattering

Resolving Two-dimensional Kinetics of the Integrin αIIbβ3-Fibrinogen Interactions Using Binding-Unbinding Correlation Spectroscopy

Disruption of disulfide-restriction at integrin knees induces activation and ligand-independent signaling of α4β7

Contact Info

Product

Resources

About