28 May 2002 Investigating intermolecular forces associated with thrombus initiation using optical tweezers
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Proceedings Volume 4622, Optical Diagnostics of Living Cells V; (2002) https://doi.org/10.1117/12.468336
Event: International Symposium on Biomedical Optics, 2002, San Jose, CA, United States
Abstract
Thrombus formation occurs when a platelet membrane receptor, glycoprotein (GP) Ib-IX-V complex, binds to its ligand, von Willebrand factor (vWf), in the subendothelium or plasma. To determine which GP Ib-IX-V amino acid sequences are critical for bond formation, we have used optical tweezers to measure forces involved in the binding of vWf to GP Ib-IX-V variants. Inasmuch as GP Ib(alpha) subunit is the primary component in human GP Ib-IX-V complex that binds to vWf, and that canine GP Ib(alpha) , on the other hand, does not bind to human vWf, we progressively replaced human GP Ib(alpha) amino acid sequences with canine GP Ib(alpha) sequences to determine the sequences essential for vWf/GP Ib(alpha) binding. After measuring the adhesive forces between optically trapped, vWf-coated beads and GP Ib(alpha) variants expressed on mammalian cells, we determined that leucine- rich repeat 2 of GP Ib(alpha) was necessary for vWf/GP Ib-IX- V bond formation. We also found that deletion of the N- terminal flanking sequence and leucine-rich repeat 1 reduced adhesion strength to vWf but did not abolish binding. While divalent cations are known to influence binding of vWf, addition of 1mM CaCl2 had no effect on measured vWf/GP Ib(alpha) bond strengths.
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Maneesh Arya, Maneesh Arya, Jose A. Lopez, Jose A. Lopez, Gabriel M. Romo, Gabriel M. Romo, Jing-Fei Dong, Jing-Fei Dong, Larry V. McIntire, Larry V. McIntire, Joel L. Moake, Joel L. Moake, Bahman Anvari, Bahman Anvari, } "Investigating intermolecular forces associated with thrombus initiation using optical tweezers", Proc. SPIE 4622, Optical Diagnostics of Living Cells V, (28 May 2002); doi: 10.1117/12.468336; https://doi.org/10.1117/12.468336
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