Novel nuclear localization signal between the two DNA-binding zinc fingers in the human vitamin D receptor

Author(s):  
Jui-Cheng Hsieh ◽  
Yoshiko Shimizu ◽  
Shinsei Minoshima ◽  
Nobuyoshi Shimizu ◽  
Carol A. Haussler ◽  
...  
2009 ◽  
Vol 29 (23) ◽  
pp. 6283-6293 ◽  
Author(s):  
Uschi Lindert ◽  
Mirjam Cramer ◽  
Michael Meuli ◽  
Oleg Georgiev ◽  
Walter Schaffner

ABSTRACT Metal-responsive transcription factor 1 (MTF-1) mediates both basal and heavy metal-induced transcription of metallothionein genes and also regulates other genes involved in the cell stress response and in metal homeostasis. In resting cells, MTF-1 localizes to both the cytoplasm and the nucleus but quantitatively accumulates in the nucleus upon metal load and under other stress conditions. Here we show that within the DNA-binding domain, a region spanning zinc fingers 1 to 3 (amino acids [aa] 137 to 228 in human MTF-1) harbors a nonconventional nuclear localization signal. This protein segment confers constitutive nuclear localization to a cytoplasmic marker protein. The deletion of the three zinc fingers impairs nuclear localization. The export of MTF-1 to the cytoplasm is controlled by a classical nuclear export signal (NES) embedded in the acidic activation domain. We show that this activation domain confers metal inducibility in distinct cell types when fused to a heterologous DNA-binding domain. Furthermore, the cause of a previously described stronger inducibility of human versus mouse MTF-1 could be narrowed down to a 3-aa difference in the NES; “humanizing” mouse MTF-1 at these three positions enhanced its metal inducibility to the level of human MTF-1.


2018 ◽  
Vol 93 (2) ◽  
pp. 75-81 ◽  
Author(s):  
Hiromasa Tabata ◽  
Akihiro Koinui ◽  
Atsushi Ogura ◽  
Daisuke Nishihara ◽  
Hiroaki Yamamoto

1995 ◽  
Vol 215 (1) ◽  
pp. 1-7 ◽  
Author(s):  
J.C. Hsieh ◽  
P.W. Jurutka ◽  
S.H. Selznick ◽  
M.C. Reeder ◽  
C.A. Haussler ◽  
...  

1996 ◽  
Vol 16 (10) ◽  
pp. 5444-5449 ◽  
Author(s):  
H Suyang ◽  
R Phillips ◽  
I Douglas ◽  
S Ghosh

Stimulation with inducers that cause persistent activation of NF-kappa B results in the degradation of the NF-kappa B inhibitors, I kappa B alpha and I kappa B beta. Despite the rapid resynthesis and accumulation of I kappa B alpha, NF-kappa B remains induced under these conditions. We now report that I kappa B beta is also resynthesized in stimulated cells and appears as an unphosphorylated protein. The unphosphorylated I kappa B beta forms a stable complex with NF-kappa B in the cytosol; however, this binding fails to mask the nuclear localization signal and DNA binding domain on NF-kappa B, and the I kappa B beta-NF-kappa B complex enters the nucleus. It appears therefore that during prolonged stimulation, I kappa B beta functions as a chaperone for NF-kappa B by protecting it from I kappa B alpha and allowing it to be transported to the nucleus.


1993 ◽  
Vol 13 (6) ◽  
pp. 3623-3631
Author(s):  
A T Tikhonenko ◽  
A R Hartman ◽  
M L Linial

The cellular proto-oncogene c-myc can acquire transforming potential by a number of different means, including retroviral transduction. The transduced allele generally contains point mutations relative to c-myc and is overexpressed in infected cells, usually as a v-Gag-Myc fusion protein. Upon synthesis, v-Gag-Myc enters the nucleus, forms complexes with its heterodimeric partner Max, and in this complex binds to DNA in a sequence-specific manner. To delineate the role for each of these events in fibroblast transformation, we introduced several mutations into the myc gene of the avian retrovirus MC29. We observed that Gag-Myc with a mutated nuclear localization signal is confined predominantly in the cytoplasm and only about 5% of the protein could be detected in the nucleus (less than the amount of endogenous c-Myc). Consequently, only a small fraction of Max is associated with Myc. However, cells infected with this mutant exhibit a completely transformed phenotype in vitro, suggesting that production of enough v-Gag-Myc to tie up all cellular Max is not needed for transformation. While the nuclear localization signal is dispensable for transformation, minimal changes in the v-Gag-Myc DNA-binding domain completely abolish its transforming potential, consistent with a role of Myc as a transcriptional regulator. One of its potential targets might be the endogenous c-myc, which is repressed in wild-type MC29-infected cells. Our experiments with MC29 mutants demonstrate that c-myc down-regulation depends on the integrity of the v-Myc DNA-binding domain and occurs at the RNA level. Hence, it is conceivable that v-Gag-Myc, either directly or circuitously, regulates c-myc transcription.


1996 ◽  
Vol 109 (10) ◽  
pp. 2443-2452 ◽  
Author(s):  
S. de la Luna ◽  
M.J. Burden ◽  
C.W. Lee ◽  
N.B. La Thangue

The cellular transcription factor E2F plays a critical role in integrating cell cycle progression with the transcription apparatus by virtue of a physical interaction and control by key regulators of the cell cycle, such as pRb, cyclins and cyclin-dependent kinases. Generic E2F DNA binding activity arises when a member of two families of proteins, E2F and DP, form heterodimeric complexes, an interaction which results in co-operative transcriptional and DNA binding activity. Here, we characterise a new and hitherto unexpected mechanism of control influencing the activity of E2F which is mediated at the level of intracellular location through a dependence on heterodimer formation for nuclear translocation. Nuclear accumulation is dramatically influenced by two distinct processes: alternative splicing of a nuclear localization signal and subunit composition of the E2F heterodimer. These data define a new level of control in the E2F transcription factor whereby interplay between subunits dictates the levels of nuclear DNA binding activity.


Sign in / Sign up

Export Citation Format

Share Document