Single-molecule imaging reveals transforming growth factor-β-induced type II receptor dimerization
- Wei Zhanga,
- Yaxin Jianga,
- Qiang Wangb,
- Xinyong Maa,
- Zeyu Xiaoa,
- Wei Zuob,
- Xiaohong Fanga,1 and
- Ye-Guang Chenb,1
- aBeijing National Laboratory for Molecular Sciences, Institute of Chemistry, Key Laboratory of Molecular Nanostructures and Nanotechnology, Chinese Academy of Sciences, Beijing 100190, P.R. China; and
- bState Key Laboratory of Biomembrane and Membrane Biotechnology, Department of Biological Sciences and Biotechnology, Tsinghua University, Beijing 100084, P. R. China
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Communicated by Chunli Bai, Chinese Academy of Sciences, Beijing, People's Republic of China, July 23, 2009 (received for review April 23, 2009)
Abstract
Transforming growth factor-β (TGF-β) elicits its signals through two transmembrane serine/threonine kinase receptors, type II (TβRII) and type I receptors. It is generally believed that the initial receptor dimerization is an essential event for receptor activation. However, previous studies suggested that TGF-β signals by binding to the preexisting TβRII homodimer. Here, using single molecule microscopy to image green fluorescent protein (GFP)-labeled TβRII on the living cell surface, we demonstrated that the receptor could exist as monomers at the low expression level in resting cells and dimerize upon TGF-β stimulation. This work reveals a model in which the activation of serine-threonine kinase receptors is also accomplished via dimerization of monomers, suggesting that receptor dimerization is a general mechanism for ligand-induced receptor activation.
Footnotes
- 1To whom correspondence may be addressed. E-mail: xfang{at}iccas.ac.cn or ygchen{at}tsinghua.edu.cn
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Author contributions: X.F. and Y.-G.C. designed research; W. Zhang, Y.J., Q.W., and X.M. performed research; Z.X. and W. Zuo contributed new reagents/analytic tools; W. Zhang, Y.J., X.F., and Y.-G.C. analyzed data; and W. Zhang, X.F., and Y.-G.C. wrote the paper.
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The authors declare no conflict of interest.
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This article contains supporting information online at www.pnas.org/cgi/content/full/0908279106/DCSupplemental.
