title: Exploring in vivo cholesterol-mediated interactions between activated EGF receptors in plasma membrane with single-molecule optical tracking.
abstract: BACKGROUND
  The first step in many cellular signaling processes occurs at various types of receptors in the plasma membrane. Membrane cholesterol can alter these signaling pathways of living cells. However, the process in which the interaction of activated receptors is modulated by cholesterol remains unclear.
  
  
  METHODS
  In this study, we measured single-molecule optical trajectories of epidermal growth factor receptors moving in the plasma membranes of two cancerous cell lines and one normal endothelial cell line. A stochastic model was developed and applied to identify critical information from single-molecule trajectories.
  
  
  RESULTS
  We discovered that unliganded epidermal growth factor receptors may reside nearby cholesterol-riched regions of the plasma membrane and can move into these lipid domains when subjected to ligand binding. The amount of membrane cholesterol considerably affects the stability of correlated motion of activated epidermal growth factor receptors.
  
  
  CONCLUSIONS
  Our results provide single-molecule evidence of membrane cholesterol in regulating signaling receptors. Because the three cell lines used for this study are quite diverse, our results may be useful to shed light on the mechanism of cholesterol-mediated interaction between activated receptors in live cells.
authors.affiliation: Department of Photonics, Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu, Taiwan.
authors.forename: Chien Y
authors.initials: CY
authors.lastname: Lin
authors.affiliation: The T.K.P. Research Center for Photonics, Chiao Tung University, 1001 Ta-Hsueh Road, Hsinchu, Taiwan.
authors.forename: Jung Y
authors.identifier: 0000-0002-4189-3779
authors.initials: JY
authors.lastname: Huang
authors.affiliation: Institute of Biomedical Engineering and Nanomedicine, National Health Research Institutes, 35, Keyan Road, Zhunan, Taiwan.
authors.forename: Leu-Wei
authors.initials: LW
authors.lastname: Lo
keywords: Diffusion; Epidermal growth factor receptor; Live cell; Plasma membrane; Single-molecule trajectory