Binding strength and activation state of single fibrinogen-integrin pairs on living cells

@article{citeulike:2599294, abstract = {Integrin activation states determine the ability of these receptors to mediate cell-matrix and cell-cell interactions. The prototypic example of this phenomenon is the platelet integrin, [alpha]IIb[beta]3. In unstimulated platelets, [alpha]IIb[beta]3 is inactive, whereas exposing platelets to an agonist such as ADP or thrombin enables [alpha]IIb[beta]3 to bind ligands such as fibrinogen and von Willebrand factor. To study the regulation of integrin activation states at the level of single molecules, we developed a model system based on laser tweezers, enabling us to determine the rupture forces required to separate single ligand-receptor pairs by using either purified proteins or intact living cells. Here, we show that rupture forces of individual fibrinogen molecules and either purified [alpha]IIb[beta]3 or [alpha]IIb[beta]3 on the surface of living platelets were 60 to 150 pN with a peak yield strength of 80-100 pN. Platelet stimulation using either ADP or the thrombin receptor-activating peptide enhanced the accessibility but not the adhesion strength of single [alpha]IIb[beta]3 molecules, indicating that there are only two states of [alpha]IIb[beta]3 activation. Thus, we found it possible to use laser tweezers to measure the regulation of forces between individual ligand-receptor pairs on living cells. This methodology can be applied to the study of other regulated cell membrane receptors using the ligand-receptor yield strength as a direct measure of receptor activation/inactivation state. 10.1073/pnas.112194999}, author = {Litvinov, Rustem I. and Shuman, Henry and Bennett, Joel S. and Weisel, John W. }, citeulike-article-id = {2599294}, doi = {10.1073/pnas.112194999}, journal = {Proceedings of the National Academy of Sciences}, keywords = {fibrinogen, strength}, month = {May}, number = {11}, pages = {7426--7431}, posted-at = {2008-03-26 17:51:37}, priority = {3}, title = {Binding strength and activation state of single fibrinogen-integrin pairs on living cells}, url = {http://dx.doi.org/10.1073/pnas.112194999}, volume = {99}, year = {2002} }

TY - JOUR ID - citeulike:2599294 L3 - citeulike-article-id:2599294 TI - Binding strength and activation state of single fibrinogen-integrin pairs on living cells JF - Proceedings of the National Academy of Sciences VL - 99 IS - 11 SP - 7426 EP - 7431 N2 - Integrin activation states determine the ability of these receptors to mediate cell-matrix and cell-cell interactions. The prototypic example of this phenomenon is the platelet integrin, [alpha]IIb[beta]3. In unstimulated platelets, [alpha]IIb[beta]3 is inactive, whereas exposing platelets to an agonist such as ADP or thrombin enables [alpha]IIb[beta]3 to bind ligands such as fibrinogen and von Willebrand factor. To study the regulation of integrin activation states at the level of single molecules, we developed a model system based on laser tweezers, enabling us to determine the rupture forces required to separate single ligand-receptor pairs by using either purified proteins or intact living cells. Here, we show that rupture forces of individual fibrinogen molecules and either purified [alpha]IIb[beta]3 or [alpha]IIb[beta]3 on the surface of living platelets were 60 to 150 pN with a peak yield strength of 80-100 pN. Platelet stimulation using either ADP or the thrombin receptor-activating peptide enhanced the accessibility but not the adhesion strength of single [alpha]IIb[beta]3 molecules, indicating that there are only two states of [alpha]IIb[beta]3 activation. Thus, we found it possible to use laser tweezers to measure the regulation of forces between individual ligand-receptor pairs on living cells. This methodology can be applied to the study of other regulated cell membrane receptors using the ligand-receptor yield strength as a direct measure of receptor activation/inactivation state. 10.1073/pnas.112194999 KW - fibrinogen KW - strength AU - Litvinov, Rustem AU - Shuman, Henry AU - Bennett, Joel AU - Weisel, John PY - 2002/05/28/ UR - http://dx.doi.org/10.1073/pnas.112194999 ER -