Analysis of intranuclear binding process of glucocorticoid receptor using fluorescence correlation spectroscopy

The diffusion properties of EGFP-hGR alpha and mutants C421G, A458T and 1566 in living cells were analyzed. The wild type and mutants C421G and A458T translocated from the cytoplasm to the nucleus after addition of Dex; however, the Brownian motions of the proteins were different. The diffusion constant of wild-type GR alpha after addition of Dex slowed to 15.6% of that in the absence of Dex, whereas those of A458T and C421G slowed to 34.8% and 61.7%, respectively. This is the first report that dimer formation is less important than the binding activity of GR alpha to GRE in the living cell. (c) 2006 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.