Stepped changes of monovalent ligand-binding force during ligand-induced clustering of integrin αIIBβ3

Chia Fen Hsieh, Bo Jui Chang, Chyi Huey Pai, Hsuan Yi Chen, Jin Wu Tsaia, Yung Hsiang Yi, Yi Ting Chiang, Da Wei Wang, Sien Chi, Long Hsu, Chi Hung Lin*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Recent evidence demonstrated that conformational changes of the integrin during receptor activation affected its binding to extracellular matrix; however, experimental assessment of ligand-receptor binding following the initial molecular interaction has rarely been carried out at a single-molecule resolution. In the present study, laser tweezers were used to measure the binding force exerted by a live Chinese hamster ovary cell that expressed integrin αIIBβ3 (CHO α IIBβ3), to the bead carrier coated with the snake venom rhodostomin that served as an activated ligand for integrin αIIBβ3. A progressive increase of total binding force over time was noticed when the bead interacted with the CHO αIIBβ3 cell; such an increase was due mainly to the recruitment of more integrin molecules to the bead-cell interface. When the binding strength exerted by a single ligand-receptor pair was derived from the "polyvalent" measurements, surprisingly, a stepped decrease of the "monovalent binding force" was noted (from 4.15 to 2.54 piconewtons (pN)); such decrease appeared to occur during the ligand-induced integrin clustering process. On the other hand, the mutant rhodostomin defective in clustering integrins exhibited only one (1.81 pN) unit binding strength.

Original languageEnglish
Pages (from-to)25466-25474
Number of pages9
JournalJournal of Biological Chemistry
Volume281
Issue number35
DOIs
StatePublished - 1 Sep 2006

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