scholarly journals Subcellular and Subnuclear Distributions of Estrogen Receptor α in Living Cells Using Green Fluorescent Protein and Immunohistochemistry

2001 ◽  
Vol 34 (6) ◽  
pp. 413-422 ◽  
Author(s):  
Maki Yoshida ◽  
Mayumi Nishi ◽  
Zenro Kizaki ◽  
Tadashi Sawada ◽  
Mitsuhiro Kawata
2001 ◽  
Vol 21 (13) ◽  
pp. 4404-4412 ◽  
Author(s):  
David L. Stenoien ◽  
Anne C. Nye ◽  
Maureen G. Mancini ◽  
Kavita Patel ◽  
Martin Dutertre ◽  
...  

ABSTRACT Studies with live cells demonstrate that agonist and antagonist rapidly (within minutes) modulate the subnuclear dynamics of estrogen receptor α (ER) and steroid receptor coactivator 1 (SRC-1). A functional cyan fluorescent protein (CFP)-taggedlac repressor-ER chimera (CFP-LacER) was used in live cells to discretely immobilize ER on stably integratedlac operator arrays to study recruitment of yellow fluorescent protein (YFP)-steroid receptor coactivators (YFP–SRC-1 and YFP-CREB binding protein [CBP]). In the absence of ligand, YFP–SRC-1 is found dispersed throughout the nucleoplasm, with a surprisingly high accumulation on the CFP-LacER arrays. Agonist addition results in the rapid (within minutes) recruitment of nucleoplasmic YFP–SRC-1, while antagonist additions diminish YFP–SRC-1–CFP-LacER associations. Less ligand-independent colocalization is observed with CFP-LacER and YFP-CBP, but agonist-induced recruitment occurs within minutes. The agonist-induced recruitment of coactivators requires helix 12 and critical residues in the ER–SRC-1 interaction surface, but not the F, AF-1, or DNA binding domains. Fluorescence recovery after photobleaching indicates that YFP–SRC-1, YFP-CBP, and CFP-LacER complexes undergo rapid (within seconds) molecular exchange even in the presence of an agonist. Taken together, these data suggest a dynamic view of receptor-coregulator interactions that is now amenable to real-time study in living cells.


1997 ◽  
Vol 139 (6) ◽  
pp. 1465-1476 ◽  
Author(s):  
Norio Sakai ◽  
Keiko Sasaki ◽  
Natsu Ikegaki ◽  
Yasuhito Shirai ◽  
Yoshitaka Ono ◽  
...  

We expressed the γ-subspecies of protein kinase C (γ-PKC) fused with green fluorescent protein (GFP) in various cell lines and observed the movement of this fusion protein in living cells under a confocal laser scanning fluorescent microscope. γ-PKC–GFP fusion protein had enzymological properties very similar to that of native γ-PKC. The fluorescence of γ-PKC– GFP was observed throughout the cytoplasm in transiently transfected COS-7 cells. Stimulation by an active phorbol ester (12-O-tetradecanoylphorbol 13-acetate [TPA]) but not by an inactive phorbol ester (4α-phorbol 12, 13-didecanoate) induced a significant translocation of γ-PKC–GFP from cytoplasm to the plasma membrane. A23187, a Ca2+ ionophore, induced a more rapid translocation of γ-PKC–GFP than TPA. The A23187-induced translocation was abolished by elimination of extracellular and intracellular Ca2+. TPA- induced translocation of γ-PKC–GFP was unidirected, while Ca2+ ionophore–induced translocation was reversible; that is, γ-PKC–GFP translocated to the membrane returned to the cytosol and finally accumulated as patchy dots on the plasma membrane. To investigate the significance of C1 and C2 domains of γ-PKC in translocation, we expressed mutant γ-PKC–GFP fusion protein in which the two cysteine rich regions in the C1 region were disrupted (designated as BS 238) or the C2 region was deleted (BS 239). BS 238 mutant was translocated by Ca2+ ionophore but not by TPA. In contrast, BS 239 mutant was translocated by TPA but not by Ca2+ ionophore. To examine the translocation of γ-PKC–GFP under physiological conditions, we expressed it in NG-108 cells, N-methyl-d-aspartate (NMDA) receptor–transfected COS-7 cells, or CHO cells expressing metabotropic glutamate receptor 1 (CHO/mGluR1 cells). In NG-108 cells , K+ depolarization induced rapid translocation of γ-PKC–GFP. In NMDA receptor–transfected COS-7 cells, application of NMDA plus glycine also translocated γ-PKC–GFP. Furthermore, rapid translocation and sequential retranslocation of γ-PKC–GFP were observed in CHO/ mGluR1 cells on stimulation with the receptor. Neither cytochalasin D nor colchicine affected the translocation of γ-PKC–GFP, indicating that translocation of γ-PKC was independent of actin and microtubule. γ-PKC–GFP fusion protein is a useful tool for investigating the molecular mechanism of γ-PKC translocation and the role of γ-PKC in the central nervous system.


2000 ◽  
Vol 113 (15) ◽  
pp. 2679-2683 ◽  
Author(s):  
K. Sugaya ◽  
M. Vigneron ◽  
P.R. Cook

RNA polymerase II is a multi-subunit enzyme responsible for transcription of most eukaryotic genes. It associates with other complexes to form enormous multifunctional ‘holoenzymes’ involved in splicing and polyadenylation. We wished to study these different complexes in living cells, so we generated cell lines expressing the largest, catalytic, subunit of the polymerase tagged with the green fluorescent protein. The tagged enzyme complements a deficiency in tsTM4 cells that have a temperature-sensitive mutation in the largest subunit. Some of the tagged subunit is incorporated into engaged transcription complexes like the wild-type protein; it both resists extraction with sarkosyl and is hyperphosphorylated at its C terminus. Remarkably, subunits bearing such a tag can be incorporated into the active enzyme, despite the size and complexity of the polymerizing complex. Therefore, these cells should prove useful in the analysis of the dynamics of transcription in living cells.


1997 ◽  
Vol 3 (S2) ◽  
pp. 139-140
Author(s):  
John Presley ◽  
Koret Hirschberg ◽  
Nelson Cole

The ts045 mutant of VSV G protein has been used in numerous studies to identify biochemical and morphological properties of membrane transport, due to its reversible misfolding and retention in the ER at 40°C and ability to traffic out of the ER and into the Golgi complex upon temperature reduction to 32oC. The dynamic properties of membrane transport intermediates of the secretory pathway, including their lifetime and fate within cells, have not until now been explored due to the inability to follow transport in single living cells. Here, we attached green fluorescent protein to the cytoplasmic tail of VSV G protein in order to visualize ER-to-Golgi and Golgi-to-plasma membrane transport in living cells. VSVG-GFP expressed in Cos cells accumulated in the ER at 40°C and translocated to the Golgi complex when shifted to 32oC. Translocation of the protein was followed using time-lapse imaging of live cells on a confocal microscope. VSVG-GFP accumulated in tubulovesicular structures scattered throughout the cell upon shift from 40°C to 15°C for three hours.


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