DNA-based digital tension probes reveal integrin forces during early cell adhesion

• Type of Material: Article
• Authors: Yun Zhang, Emory University; Chenghao Ge, Georgia Institute of Technology; Cheng Zhu, Georgia Institute of Technology; Khalid Salaita, Emory University
• Language: English
• Date: 2014-10-24
• Publisher: Nature Publishing Group: Nature Communications
• Publication Version: Final Published Version
• Copyright Statement: © 2014 Nature Publishing Group
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1038/ncomms6167
• Title of Journal or Parent Work: Nature Communications
• ISSN: 2041-1723
• Volume: 5
• Start Page: 5167
• End Page: 5167
• Grant/Funding Information: The authors are grateful for support from the NIH (R01-GM097399), the Alfred P. Sloan Research Fellowship, the Camille-Dreyfus Teacher-Scholar Award, and the NSF CAREER Award (1350829).
• Keywords: Force sensing; Mechanotransduction; FRET sensor; Focal adhesion
• Research Categories: Chemistry, Biochemistry; Engineering, Biomedical; Biology, General

Abstract

Mechanical stimuli profoundly alter cell fate, yet the mechanisms underlying mechanotransduction remain obscure due to a lack of methods for molecular force imaging. Here, to address this need, we develop a new class of molecular tension probes that function as a switch to generate a 20–30-fold increase in fluorescence upon experiencing a threshold piconewton force. The probes employ immobilized DNA-hairpins with tunable force response thresholds, ligands, and fluorescence reporters. Quantitative imaging reveals that integrin tension is highly dynamic and increases with an increasing integrin density during adhesion formation. Mixtures of fluorophore-encoded probes show integrin mechanical preference for cyclized-RGD over linear-RGD peptides. Multiplexed probes with variable guanine-cytosine content within their hairpins reveal integrin preference for the more stable probes at the leading tip of growing adhesions near the cell edge. DNA-based tension probes are among the most sensitive optical force reporters to date, overcoming the force and spatial-resolution limitations of traction force microscopy.