Identification of stepped changes of binding affinity during interactions between the disintegrin rhodostomin and integrin α IIb β 3 in living cells using optical tweezers

Chia Fen Hsieh*, Bo Jui Chang, Chyi Huey Pai, Hsuan Yi Chen, Sien Chi, Long Hsu, Jin Wu Tsai, Chi Hung Lin

*Corresponding author for this work

研究成果: Conference article同行評審

摘要

Integrin receptors serve as both mechanical links and signal transduction mediators between the cell and its environment. Experimental evidence demonstrates that conformational changes and lateral clustering of the integrin proteins may affect their binding to ligands and regulate downstream cellular responses; however, experimental links between the structural and functional correlations of the ligand-receptor interactions are not yet elucidated. In the present report, we utilized optical tweezers to measure the dynamic binding between the snake venom rhodostomin, coated on a microparticle and functioned as a ligand, and the membrane receptor integrin α IIb β 3 expressed on a Chinese Hamster Ovary (CHO) cell. A progressive increase of total binding affinity was found between the bead and CHO cell in the first 300 sec following optical tweezers-guided contact. Further analysis of the cumulative data revealed the presence of "unit binding force" presumably exerted by a single rhodostomin-integrin pair. Interestingly, two such units were found. Among the measurements of less total binding forces, presumably taken at the early stage of ligand-receptor interactions, a unit of 4.15 pN per molecule pair was derived. This unit force dropped to 2.54 pN per molecule pair toward the later stage of interactions when the total binding forces were relatively large. This stepped change of single molecule pair binding affinity was not found when mutant rhodostomin proteins were used as ligands (a single unit of 1.81 pN per pair was found). These results were interpreted along with the current knowledge about the conformational changes of integrins during the "molecule activation" process.

原文English
文章編號27
頁(從 - 到)215-224
頁數10
期刊Proceedings of SPIE - The International Society for Optical Engineering
5514
DOIs
出版狀態Published - 1 十二月 2004
事件Optical Trapping and Optical Micromanipulation - Denver, CO, United States
持續時間: 2 八月 20046 八月 2004

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