It has been shown previously that glucocorticoid receptors (GRs) that have undergone hormone-dependent translocation to the nucleus and have subsequently exited the nucleus upon hormone withdrawal are unable to recycle into the nucleus if cells are treated during hormone withdrawal with okadaic acid, a cell-permeable inhibitor of certain serine/threonine protein phosphatases. Using a green fluorescent protein (GFP) GR chimera (GFP-GR), we report here that okadaic acid inhibition of steroid-dependent receptor recycling to the nucleus is abrogated in cells treated for 1 h with colcemid to eliminate microtubule networks prior to steroid addition. After withdrawal of colcemid, normal cytoskeletal architecture is restored and okadaic acid inhibition of steroid-dependent GFP-GR nuclear recycling is restored. When okadaic acid is present during hormone withdrawal, GR that is recycled to the cytoplasm becomes complexed with hsp90 and binds steroid, but it does not undergo the normal agonist-dependent dissociation from hsp90 upon retreatment with steroid. However, when the cytoskeleton is disrupted by colcemid, the GR in okadaic acid-treated cells recycles from the cytoplasm to the nucleus in an agonist-dependent manner without dissociating from hsp90. This suggests that under physiological conditions where the cytoskeleton is intact, a dephosphorylation event is required for loss of high affinity binding to hsp90 that is required for receptor translocation through the cytoplasm to the nucleus along cytoskeletal tracts. It has been shown previously that glucocorticoid receptors (GRs) that have undergone hormone-dependent translocation to the nucleus and have subsequently exited the nucleus upon hormone withdrawal are unable to recycle into the nucleus if cells are treated during hormone withdrawal with okadaic acid, a cell-permeable inhibitor of certain serine/threonine protein phosphatases. Using a green fluorescent protein (GFP) GR chimera (GFP-GR), we report here that okadaic acid inhibition of steroid-dependent receptor recycling to the nucleus is abrogated in cells treated for 1 h with colcemid to eliminate microtubule networks prior to steroid addition. After withdrawal of colcemid, normal cytoskeletal architecture is restored and okadaic acid inhibition of steroid-dependent GFP-GR nuclear recycling is restored. When okadaic acid is present during hormone withdrawal, GR that is recycled to the cytoplasm becomes complexed with hsp90 and binds steroid, but it does not undergo the normal agonist-dependent dissociation from hsp90 upon retreatment with steroid. However, when the cytoskeleton is disrupted by colcemid, the GR in okadaic acid-treated cells recycles from the cytoplasm to the nucleus in an agonist-dependent manner without dissociating from hsp90. This suggests that under physiological conditions where the cytoskeleton is intact, a dephosphorylation event is required for loss of high affinity binding to hsp90 that is required for receptor translocation through the cytoplasm to the nucleus along cytoskeletal tracts. Although targeted movement of certain signaling proteins such as the steroid receptors, signal transducers and activators of transcription, and mitogen-activated protein kinases through the cytoplasm to the nucleus is necessary for signal transduction, virtually nothing is known about the machinery that enables these protein solutes to traverse the cytoplasm. Steroid receptors undergo a constant shuttling into and out of the nucleus (1Guichon-Mantel A. Lescop P. Christin-Maitre S. Loosfelt H. Perrot-Applanat M. Milgrom E. EMBO J. 1991; 10: 3851-3859Crossref PubMed Scopus (249) Google Scholar, 2Chandran U.R. DeFranco D.B. Mol. Endocrinol. 1992; 6: 837-844PubMed Google Scholar, 3Madan A.P. DeFranco D.B. Proc. Natl. Acad. Sci. U. S. A. 1993; 90: 3588-3592Crossref PubMed Scopus (144) Google Scholar, 4Dauvois S. White R. Parker M.G. J. Cell Sci. 1993; 106: 1377-1388Crossref PubMed Google Scholar) (for review, see Ref. 5DeFranco D.B. Madan A.P. Tang Y. Chandran U.R. Xiao N. Yang J. Vitam. Horm. 1995; 51: 315-338Crossref PubMed Scopus (82) Google Scholar) and, depending upon the receptor and the cell type, the hormone-free, untransformed receptor may be predominantly nuclear or cytoplasmic in location. In most cells, the untransformed glucocorticoid receptor (GR) 1The abbreviations used are: GR, glucocorticoid receptor; NLS, nuclear localization signal; DMEM, Dulbecco's modified Eagle's medium; hsp, heat shock protein; GFP, green fluorescent protein; CORT, corticosterone; OA, okadaic acid; TES, 2-{[2-hydroxy-1,1-bis-(hydroxymethyl)ethyl]amino}ethanesulfonic acid. is predominantly localized in the cytoplasm, and upon hormone binding and transformation, the receptor translocates to the nucleus (6Picard D. Yamamoto K.R. EMBO J. 1987; 6: 3333-3340Crossref PubMed Scopus (724) Google Scholar, 7Qi M. Hamilton B.J. DeFranco D.B. Mol. Endocrinol. 1989; 3: 1279-1288Crossref PubMed Scopus (73) Google Scholar, 8Czar M.J. Lyons R.H. Welsh M.J. Renoir J.M. Pratt W.B. Mol. Endocrinol. 1995; 9: 1549-1560PubMed Google Scholar) in a manner that is determined by nuclear localization signal (NLS) sequences in the receptor (6Picard D. Yamamoto K.R. EMBO J. 1987; 6: 3333-3340Crossref PubMed Scopus (724) Google Scholar). Because movement of the receptor can be initiated by addition of steroid, the GR is a particularly useful model for studying targeted protein movement through the cytoplasm. Studies performed with inhibitors suggest that the protein chaperone hsp90 and an okadaic acid-sensitive protein phosphatase may each play a role in GR translocation from the cytoplasm to the nucleus. The involvement of hsp90 in receptor movement is likely to involve dynamic assembly and disassembly of GR·hsp90 heterocomplexes. For example, Yang and DeFranco (9Yang J. DeFranco D.B. Mol. Endocrinol. 1996; 10: 3-13Crossref PubMed Scopus (88) Google Scholar) showed that molybdate, which binds to hsp90 and stabilizes GR·hsp90 heterocomplexes in vivo (10Raaka B.M. Finnerty M. Sun E. Samuels H.H. J. Biol. Chem. 1985; 260: 14009-14015Abstract Full Text PDF PubMed Google Scholar), trapped the GR in the cytoplasm of cells chronically exposed to hormone. It was suggested that the receptors can be exported from nuclei after hormone-dependent translocation, but they cannot be reimported into nuclei in the presence of molybdate (10Raaka B.M. Finnerty M. Sun E. Samuels H.H. J. Biol. Chem. 1985; 260: 14009-14015Abstract Full Text PDF PubMed Google Scholar). Association of receptors with hsp90 is a dynamic process (11Smith D.F. Mol. Endocrinol. 1993; 7: 1418-1429Crossref PubMed Scopus (251) Google Scholar), and it has been shown that GR and hsp90 can move together from the cytoplasm to the nucleus (12Kang K.I. Devin J. Cadepond F. Jibard N. Guichon-Mantel A. Baulieu E.E. Catelli M.G. Proc. Natl. Acad. Sci. U. S. A. 1994; 91: 340-344Crossref PubMed Scopus (121) Google Scholar). It has also been shown that treatment of cells with geldanamycin, an antibiotic that binds to hsp90 (13Whitesell L. Mimnaugh E.G. DeCosta B. Myers C.E. Neckers L.M. Proc. Natl. Acad. Sci. U. S. A. 1994; 91: 8324-8328Crossref PubMed Scopus (1337) Google Scholar) at its nucleotide binding site (14Prodromou C. Roe S.M. O'Brien R. Ladbury J.E. Piper P.W. Pearl L.H. Cell. 1997; 90: 65-75Abstract Full Text Full Text PDF PubMed Scopus (1125) Google Scholar) and prevents formation of normal receptor·hsp90 heterocomplexes (15Smith D.F. Whitesell L. Nair S.C. Chen S. Prapapanich V. Rimerman R.A. Mol. Cell. Biol. 1995; 15: 6804-6812Crossref PubMed Scopus (272) Google Scholar), impedes steroid-induced movement of the GR from the cytoplasm to the nucleus (16Czar M.J. Galigniana M.D. Silverstein A.M. Pratt W.B. Biochemistry. 1997; 36: 7776-7785Crossref PubMed Scopus (134) Google Scholar). Taken together, these observations are consistent with the notion that hsp90 plays some role in GR movement. The notion that a phosphatase may be required for receptor shuttling evolved from the work of Qi et al. (7Qi M. Hamilton B.J. DeFranco D.B. Mol. Endocrinol. 1989; 3: 1279-1288Crossref PubMed Scopus (73) Google Scholar, 17Qi M. Stasenko L.J. DeFranco D.B. Mol. Endocrinol. 1990; 4: 455-464Crossref PubMed Scopus (41) Google Scholar), who found that GRs in cells transformed with v-Mos, an oncoprotein that is a cytoplasmic serine/threonine protein kinase, undergo hormone-dependent transfer to the nucleus but that they are inefficiently retained, and they cycle back to the cytoplasm, where they do not regain the capacity for hormone-dependent translocation. Subsequently, DeFranco et al. (18DeFranco D.B. Qi M. Borror K.C. Garabedian M.J. Brautigan D.L. Mol. Endocrinol. 1991; 5: 1215-1228Crossref PubMed Scopus (123) Google Scholar) showed that okadaic acid, a serine/threonine protein phosphatase inhibitor, acts like v-Mos to trap GR that has cycled out of the nucleus into the cytoplasm in a form that cannot undergo hormone-dependent recycling to the nucleus. These observations suggest that a cytoplasmic phosphatase is required for recycling of GR that has passed through stages of nuclear import, transcriptional activation, and nuclear export (18DeFranco D.B. Qi M. Borror K.C. Garabedian M.J. Brautigan D.L. Mol. Endocrinol. 1991; 5: 1215-1228Crossref PubMed Scopus (123) Google Scholar). It is not known whether the phosphatase activity is required for GR transformation to a state that can be translocated or whether it is required for subsequent movement of the transformed receptor (18DeFranco D.B. Qi M. Borror K.C. Garabedian M.J. Brautigan D.L. Mol. Endocrinol. 1991; 5: 1215-1228Crossref PubMed Scopus (123) Google Scholar). Recently, we have used cytoskeletal disrupting agents, such as colcemid and cytochalasin D, and a fusion protein of murine GR withAequorea green fluorescent protein (GFP-GR) to determine whether there is any linkage between hsp90-dependent receptor movement and the cytoskeleton (19Galigniana M.D. Scruggs J.L. Herrington J. Welsh M.J. Carter-Su C. Housley P.R. Pratt W.B. Mol. Endocrinol. 1998; 12: 1903-1913Crossref PubMed Scopus (156) Google Scholar). As previously reported by Perrot-Applanat et al. (t12∼5min) steroid-dependent translocation to the nucleus both in cells with intact cytoskeleton and in cells with completely disrupted cytoskeletal networks. However, in cells with a normal cytoskeleton, the hsp90 inhibitor geldanamycin slowed translocation of the GFP-GR by close to an order of magnitude (t12∼45min), whereas in cells with disrupted cytoskeletal networks, geldanamycin had no effect on the translocation rate (t12∼5min). This suggests two mechanisms of GR movement. Under physiological conditions where the cytoskeleton is intact, diffusion is limited, and the GFP-GR utilizes a movement machinery in which the activity of hsp90 plays a role. In cells where the cytoskeletal networks have been artifactually disrupted, movement is still steroid-dependent, but the transformed GFP-GR moves through the cytoplasm by diffusion and is not affected by geldanamycin. In this work, we show that treatment of cells with okadaic acid inhibits GR transformation as defined by loss of its high affinity association with hsp90, and we show that disruption of microtubules with colcemid eliminates the okadaic acid block of hormone-dependent recycling of GFP-GR to the nucleus. We suggest that under physiological conditions where the cytoskeleton is intact, the GR shuttles between the cytoplasm and the nucleus with the help of a machinery that utilizes cytoskeletal tracts, involves the dynamic activity of hsp90, and requires the activity of an okadaic acid-sensitive phosphatase. However, when the cytoskeleton is disrupted, the GR moves through the cytoplasm by diffusion in a manner that is still steroid-dependent but does not require the okadaic acid-sensitive phosphatase activity and hsp90 dissociation. NIH/3T3 mouse embryo fibroblasts were purchased from the American Type Culture Collection (Rockville, MD). Phenol red-free Dulbecco's modified Eagle's medium (DMEM) and LipofectAMINE were from Life Technologies, was from the and of the and were from receptor was from and the was from cells the J.E. E. J.M. F. J. Biol. Chem. 1991; Full Text PDF PubMed Google Scholar) were by of the GFP-GR was previously (19Galigniana M.D. Scruggs J.L. Herrington J. Welsh M.J. Carter-Su C. Housley P.R. Pratt W.B. Mol. Endocrinol. 1998; 12: 1903-1913Crossref PubMed Scopus (156) Google Scholar). NIH/3T3 cells were on in with in When cells were they were with medium and for an in For each of GFP-GR a of and of LipofectAMINE in of medium was to of and to were with the for h at and the medium was by medium for an h of the of this the were with and in red-free with The cells were used for GFP-GR translocation For receptor translocation and steroid withdrawal cells as were for 1 h with to GFP-GR translocation to the nucleus. The medium was and cells were and for h in red-free with with or without okadaic acid. After was for 1 h to GFP-GR recycling into the nucleus. For microtubule colcemid was 1 h prior to of For geldanamycin inhibition of translocation, cells were for h at with to receptor and geldanamycin was during the h at to with the the of the h at cells were at for to steroid-dependent GFP-GR translocation. the of the with the were with at and and by in for were with and the were a with of in were with a and a The in 1 were for GFP-GR translocation as we have previously (19Galigniana M.D. Scruggs J.L. Herrington J. Welsh M.J. Carter-Su C. Housley P.R. Pratt W.B. Mol. Endocrinol. 1998; 12: 1903-1913Crossref PubMed Scopus (156) Google Scholar), a of for nuclear cytoplasmic for nuclear cytoplasmic for nuclear to cytoplasmic 1 for nuclear cytoplasmic and for nuclear cytoplasmic The translocation the from in which cells were of was by of by a cells treated with and okadaic acid, as in were in of 1 and by Cell were for at with the the The GR was from of with as previously (16Czar M.J. Galigniana M.D. Silverstein A.M. Pratt W.B. Biochemistry. 1997; 36: 7776-7785Crossref PubMed Scopus (134) Google Scholar). The were by in 1 of TES, acid and in with and proteins were on After transfer to the GR was with and hsp90 with 1 and the were a determine whether okadaic acid agonist-dependent recycling of the GFP-GR in the manner as previously reported for GR in fibroblasts (18DeFranco D.B. Qi M. Borror K.C. Garabedian M.J. Brautigan D.L. Mol. Endocrinol. 1991; 5: 1215-1228Crossref PubMed Scopus (123) Google Scholar), we performed the in the to In cells the fusion protein is localized to the cytoplasm in the of steroid 1 and is translocated to the nucleus when cells are with the 1 The agonist-dependent translocation is in cells with okadaic acid Under both conditions with and without okadaic withdrawal of for h is by of the GFP-GR to the cytoplasm and In the of okadaic acid, retreatment with recycling of the GFP-GR to the nucleus 1 However, in the presence of okadaic acid, agonist-dependent recycling to the nucleus is 1 the of the of GFP-GR to the cytoplasm upon withdrawal of In of the in this work, we a withdrawal retreatment with the of okadaic acid inhibition of agonist-dependent GFP-GR recycling to the nucleus. In this cells were treated with to the GFP-GR to the nucleus and in the presence of of okadaic acid. the of the withdrawal was to each and the were for an 1 h to the GFP-GR to the nucleus. okadaic acid, recycling to the nucleus is but at inhibition is In the of the in this work, we okadaic acid, which is the required for inhibition of GFP-GR recycling to the nucleus. determine the effect of cytoskeletal disruption on okadaic acid inhibition of GFP-GR cells were in the presence or of okadaic acid and treated for 1 h with We have shown previously that a treatment with colcemid completely eliminates microtubules in cells (19Galigniana M.D. Scruggs J.L. Herrington J. Welsh M.J. Carter-Su C. Housley P.R. Pratt W.B. Mol. Endocrinol. 1998; 12: 1903-1913Crossref PubMed Scopus (156) Google Scholar). As shown in the GFP-GR is predominantly cytoplasmic in cells that have been in the presence of okadaic acid and treated with colcemid However, when these cells with disrupted cytoskeleton are treated with there is translocation of the GFP-GR to the in the presence of okadaic acid In cells that were treated but not exposed to colcemid, GFP-GR translocation to the nucleus was by okadaic acid the colcemid treatment restored GFP-GR recycling to okadaic acid-treated The effect of cytoskeletal disruption on the rate of nuclear of the GFP-GR is shown in at a rate (t12∼5min) in okadaic cells with disrupted cytoskeleton as in cells with an intact cytoskeletal In cells in the presence of okadaic acid and not treated with colcemid about of the cytoplasmic move to the nucleus the after of but a of movement is and the of the in the cytoplasm. The GFP-GR that moves to the nucleus under this may be GFP-GR that was during the withdrawal and it has not cycled through the it is not affected by okadaic acid, as shown in D. In the in okadaic acid-treated cells where the cytoskeleton has been disrupted by colcemid undergo nuclear at the rate as in cells not treated with okadaic acid. In cells in the presence of okadaic acid were treated with or and for 1 h in okadaic medium prior to treatment with It is that the okadaic acid inhibition of GFP-GR shown in is when cells are of okadaic acid, as shown in As shown in the agonist-dependent nuclear of about of the cytoplasmic that in okadaic acid-treated cells with is if the hsp90 inhibitor geldanamycin is present during the with the inhibition of with okadaic acid the inhibition of by geldanamycin and okadaic acid together is by the cells We have shown previously that the cytoskeletal to normal when cells with completely disrupted microtubules are for a in medium (19Galigniana M.D. Scruggs J.L. Herrington J. Welsh M.J. Carter-Su C. Housley P.R. Pratt W.B. Mol. Endocrinol. 1998; 12: 1903-1913Crossref PubMed Scopus (156) Google Scholar). that of cells in medium okadaic acid inhibition of GFP-GR nuclear to cells with The that it is disruption of the cytoskeleton that the GFP-GR in cells to through the cytoplasm to the nucleus the of okadaic acid is by the of conditions and in B. In this the cells that were in the presence of okadaic acid were for 1 h with or with a of that does not with L. Biochemistry. 9: PubMed Scopus Google Scholar). We have previously reported that cells treated with 1 whereas cells treated with 1 do not (19Galigniana M.D. Scruggs J.L. Herrington J. Welsh M.J. Carter-Su C. Housley P.R. Pratt W.B. Mol. Endocrinol. 1998; 12: 1903-1913Crossref PubMed Scopus (156) Google Scholar). As shown in okadaic acid not GFP-GR nuclear in cells but it in cells The GR is from cells as a GR·hsp90 and after treatment of cells with steroid, it is from as the GR (for review, see Ref. W.B. 1997; PubMed Scopus Google Scholar). This steroid-dependent transformation of the receptor has been as a to translocation of the GR from the cytoplasm to the nucleus. In the to we whether okadaic acid receptor In this cells were treated with and okadaic acid as the cells were and the cell GR was and for hsp90 by As shown in receptors that have undergone agonist-dependent translocation to the nucleus and been in the presence or of okadaic acid are in heterocomplexes with hsp90. retreatment of cells in the of okadaic acid GR, whereas treatment of cells in the presence of okadaic acid GR·hsp90 heterocomplexes. In cells in the presence of okadaic acid, there is no nuclear movement after of retreatment with and after 1 h of receptors in these cells are as GR·hsp90 heterocomplexes not These suggest that an okadaic acid-sensitive phosphatase activity is required for transformation of glucocorticoid receptors that have been cycled into and out of the nucleus. We showed in that cytoskeletal disruption with colcemid nuclear transfer of receptors in cells in the presence of okadaic acid, and under these GFP-GR recycles to the nucleus We have also shown that the GR to the nucleus in cells M.J. Lyons R.H. Welsh M.J. Renoir J.M. Pratt W.B. Mol. Endocrinol. 1995; 9: 1549-1560PubMed Google Scholar). we whether receptors that were recycled into the nucleus in cells that were in the presence of okadaic acid and colcemid were in the or The after steroid treatment was for the to the GR that has to the nucleus is still in the after cell After of steroid most of the GR is in the nuclear of cells not As shown in receptors that have been in the presence or of okadaic acid and treated with colcemid are in heterocomplexes with hsp90. treatment of cells with a disrupted cytoskeleton that were in the of okadaic acid in GR, but in cells in the presence of okadaic acid, receptors in with hsp90. the receptors in okadaic cells where the cytoskeleton is disrupted undergo agonist-dependent translocation to the nucleus without transformation as defined by agonist-dependent dissociation of the GR·hsp90 inhibitors of steroid-dependent GR cytoplasmic nuclear translocation have been as geldanamycin and okadaic acid. inhibits the rate of receptor translocation, but in of the receptors localized in the nucleus (16Czar M.J. Galigniana M.D. Silverstein A.M. Pratt W.B. Biochemistry. 1997; 36: 7776-7785Crossref PubMed Scopus (134) Google Scholar, M.D. Scruggs J.L. Herrington J. Welsh M.J. Carter-Su C. Housley P.R. Pratt W.B. Mol. Endocrinol. 1998; 12: 1903-1913Crossref PubMed Scopus (156) Google Scholar). inhibits both the transfer of the GR (16Czar M.J. Galigniana M.D. Silverstein A.M. Pratt W.B. Biochemistry. 1997; 36: 7776-7785Crossref PubMed Scopus (134) Google Scholar, M.D. Scruggs J.L. Herrington J. Welsh M.J. Carter-Su C. Housley P.R. Pratt W.B. Mol. Endocrinol. 1998; 12: 1903-1913Crossref PubMed Scopus (156) Google Scholar) as as the recycling of GR that has exited the nucleus upon withdrawal of hormone and not Because geldanamycin is an hsp90 inhibitor, we have suggested that dynamic assembly of GR heterocomplexes with hsp90 and its such as binding protein by the chaperone plays a role in GR movement through the cytoplasm. Because geldanamycin but does not block GR it that the role of the chaperone is to movement. it does by the association of the receptor with a of movement machinery with which the receptor when assembly of GR·hsp90 heterocomplexes is by geldanamycin. In to geldanamycin, okadaic acid does not the steroid-dependent transfer of the GR from cytoplasm to it inhibits the recycling of receptors that have passed through the cycle of nuclear import, transcriptional activation, and nuclear export (18DeFranco D.B. Qi M. Borror K.C. Garabedian M.J. Brautigan D.L. Mol. Endocrinol. 1991; 5: 1215-1228Crossref PubMed Scopus (123) Google Scholar) in to inhibition of the rate of okadaic acid recycling of the of receptors acid to block receptor recycling by a dephosphorylation event that is required for steroid-dependent receptor transformation The GR is a (for review, see Ref. E. J.E. A. 1992; Google Scholar) that becomes after cells are exposed to E. D.B. A. J. Biol. Chem. 1989; Full Text PDF PubMed Google Scholar, S. B. J. Biol. Chem. 1989; Full Text PDF PubMed Google Scholar). of the GR be the event required for receptor transformation, but of the untransformed receptor are also hsp90 and binding protein and dephosphorylation or the dephosphorylation of protein may be for receptor transformation in intact we have receptor transformation by the in the of receptors as GR·hsp90 heterocomplexes from cells that were with This steroid-dependent transformation of the receptor to a form that is no in with hsp90 is required to the GR to with the movement machinery in normal cells with intact In to receptor·hsp90 or receptor·hsp90 which are localized to the nucleus (for review, see Ref. W.B. 1997; PubMed Scopus Google Scholar), both of the GR to be or when the GR is in with hsp90. This may the GR is with the notion that the is upon GR transformation, it has been shown that dissociation of GR from with hsp90 of an to the J.M. Mol. Endocrinol. 1989; 3: PubMed Scopus Google Scholar, D. E. J.M. Yamamoto K.R. Pratt W.B. Biochemistry. 1993; PubMed Scopus Google Scholar). In cells that have been in the presence of okadaic acid, the GR is in with hsp90 and it binds steroid (18DeFranco D.B. Qi M. Borror K.C. Garabedian M.J. Brautigan D.L. Mol. Endocrinol. 1991; 5: 1215-1228Crossref PubMed Scopus (123) Google Scholar), but receptor transformation as by to GR is it was shown that microtubule disruption does not cytoplasmic nuclear translocation of the receptor M. Lescop P. Milgrom E. J. Cell Biol. 1992; PubMed Scopus Google Scholar) or the GR M.J. Lyons R.H. Welsh M.J. Renoir J.M. Pratt W.B. Mol. Endocrinol. 1995; 9: 1549-1560PubMed Google Scholar), and it does not transcriptional by the GR D. J. Steroid Mol. Biol. 1994; 51: PubMed Scopus Google Scholar). In cells treated with colcemid, geldanamycin (19Galigniana M.D. Scruggs J.L. Herrington J. Welsh M.J. Carter-Su C. Housley P.R. Pratt W.B. Mol. Endocrinol. 1998; 12: 1903-1913Crossref PubMed Scopus (156) Google Scholar) okadaic acid inhibits cytoplasmic nuclear translocation of the when the cytoskeleton is disrupted, the GR to move by a model for the normal cell be like the GR moves through the cytoplasm on cytoskeletal the of When the cytoskeletal is intact, diffusion of protein solutes like the GR is limited, and in some dynamic of the transformed GR with hsp90 a between the and the movement In the association of the untransformed GR with hsp90 of to acid to block receptor transformation, which is required for movement along the movement We that when the cytoskeleton is disrupted, a on diffusion of protein solutes has been and the GR may through the cytoplasm, with its through the nuclear determined by with nuclear proteins such as (for of the nuclear of steroid receptors, see Ref. 5DeFranco D.B. Madan A.P. Tang Y. Chandran U.R. Xiao N. Yang J. Vitam. Horm. 1995; 51: 315-338Crossref PubMed Scopus (82) Google Scholar). It is that recycling of the GR in okadaic cells treated with colcemid is steroid-dependent and under these the GR to in association with hsp90 steroid-dependent event dissociation from hsp90 have such that GR transformation is from GR movement in the cell treated with both colcemid and okadaic acid. Because Perrot-Applanat et al. M. Lescop P. Milgrom E. J. Cell Biol. 1992; PubMed Scopus Google Scholar) that the receptor move from the cytoplasm to the nucleus in cells where the cytoskeletal networks were completely disrupted, it has been that the cytoskeleton is not in steroid receptor movement through the cytoplasm of the normal The observations in this and of Galigniana et al. (19Galigniana M.D. Scruggs J.L. Herrington J. Welsh M.J. Carter-Su C. Housley P.R. Pratt W.B. Mol. Endocrinol. 1998; 12: 1903-1913Crossref PubMed Scopus (156) Google Scholar) suggest that there are two movement mechanisms and that intact cytoskeleton is required for GR movement in the normal
No takes yet. Share an insight, caveat, or question.
Galigniana et al. (1999) studied this question.
Synapse has enriched 5 related papers. Consider them for comparative context: