Monomeric type I and type III transforming growth factor-β receptors and their dimerization revealed by single-molecule imaging  

作　　者：Wei Zhang Jinghe Yuan Yong Yang Li Xu Qiang Wang Wei Zuo Xiaohong Fang Ye-Guang Chen 

机构地区：[1]Beifing National Laboratory for Molecular Sciences, Institute of Chemistry, Key Laboratory of Molecular Nanostructures and Nanotechnology, Chinese Academy of Sciences, Beijing 100190, China [2]State Key Laboratory of Biomembrane and Membrane Biotechnology, School of Life Sciences, Tsinghua University, Beijing 100084, China

出　　处：《Cell Research》2010年第11期1216-1223,共8页细胞研究（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China （90713024, 20821003, 30921004）, the National Basic Research Program of China （2007CB935601, 2010CB833706） and the Chinese Academy of Sciences.

摘　　要：Transforming growth factor-β （TGF-β） binds with two transmembrane serine/threonine kinase receptors, type Ⅱ （TβRII） and type Ⅰ receptors （TβRⅠ）, and one accessory receptor, type Ⅲ receptor （TβRⅢ）, to transduce signals across cell membranes. Previous biochemical studies suggested that TβRI and TβRIII are preexisted homo-dimers. Using single-molecule microscopy to image green fluorescent protein-labeled membrane proteins, for the first time we have demonstrated that TβRI and TβRⅢ could exist as monomers at a low expression level. Upon TGF-β1 stimu- lation, TβRI follows the general ligand-induced receptor dimerization model for activation, but this process is TβRⅡ- dependent. The monomeric status of the non-kinase receptor TβRⅢ is unchanged in the presence of TGF-β1. With the increase of receptor expression, both TβRI and TβRIII can be assembled into dimers on cell surfaces.

关 键 词：single-molecule fluorescence TGF-β signaling Type I TGF-β receptor Type Ⅲ TGF-β receptor subunit stoi-chiometry 

分 类 号：Q516[生物学—生物化学] O629.73[理学—有机化学]