Nature Cell Biology
3, 15 - 23 (2001)
Published online: 30 November 2000; | doi:10.1038/35050515
FRAP reveals that mobility of oestrogen receptor- is ligand- and proteasome-dependentDavid L. Stenoien, Kavita Patel, Maureen G. Mancini, Martin Dutertre, Carolyn L. Smith, Bert W. O'Malley
& Michael A. Mancini
Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
Correspondence should be addressed to Michael A. Mancini mancini@bcm.tmc.eduHere we report the use of fluorescence recovery after photobleaching (FRAP) to examine the intranuclear dynamics of fluorescent oestrogen receptor- (ER). After bleaching, unliganded ER exhibits high mobility (recovery t
1/2 < 1 s). Agonist (oestradiol; E2) or partial antagonist (4-hydroxytamoxifen) slows ER recovery (t
1/2  5−6 s), whereas the pure antagonist (ICI 182,780) and, surprisingly, proteasome inhibitors each immobilize ER to the nuclear matrix. Dual FRAP experiments show that fluorescent ER and SRC-1 exhibit similar dynamics only in the presence of E2. In contrast to reports that several nuclear proteins show uniform dynamics, ER exhibits differential mobility depending upon several factors that are linked to its transcription function.
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