抄録
Visualizing how signals are transmitted within a living cell has long been a goal, which has now been realized by probes based on the principle of fluorescence resonance energy transfer (FRET). Variants of green fluorescent protein (GFP) enabled the preparation of genetically-encoded FRET probes, and their application has been expanded for use in many areas of biology. In this symposium, I will present our recent data obtained with FRET probes for Rho-family GTPases, which regulate various aspects of cell function by controlling cytoskeletal changes. In migrating fibroblasts and epithelial cells, the level of RhoA activity is high both at the contractile tail and at the leading edge, whereas Rac1 and Cdc42 activities are high only at the leading edge. In cells stimulated with epidermal growth factor or nerve growth factor, activities of Rac1 and Cdc42 were transiently elevated in a broad area of plasma membrane, followed by localized activation at nascent lamellipodia. Upon epidermal growth factor stimulation, RhoA activity decreased diffusely at plasma membrane, but persisted at the edge of membrane ruffles. Thus, it has been revealed that the activities of Rho-family GTPases are elaborately regulated in time- and space-dependent manner. [Jpn J Physiol 55 Suppl:S29 (2005)]
