Lateral diffusion of TGF-β type I receptor studied by single-molecule imaging

In this report, we investigated the lateral diffusion of transforming growth factor beta (TGF-beta) type I receptor (T beta RI) in living cells by imaging and tracking individual green fluorescent protein tagged T beta RI on the cell membrane. We found that when co-expressed with TGF-beta type 11 receptor (T beta RII), the mobility of T beta RI decreased significantly after TGF-beta 1 stimulation. However, in the cells that had been depleted of cholesterol with Nystatin or methyl-beta-cyclodextrin, the diffusion rate of T beta RI was not changed by TGF-beta 1 treatment. Our observations suggest that membrane lipid-rafts provide an environment that facilitates the association of T beta RI and T beta RII for cell signaling. (c) 2007 Elsevier Inc. All rights reserved.