Comparative study of the interactions between fungal transcription factor nuclear localization sequences with mammalian and fungal importin-alpha

ABSTRACT Several different transcription factors, including estrogen receptor, progesterone receptor, and ETS family members, have been implicated in human breast cancer, indicating that transcription factor-induced alterations in gene expression underlie mammary cell transformation. ESE-1 is an epithelium-specific ETS transcription factor that contains two distinguishing domains, a serine- and aspartic acid-rich (SAR) domain and an AT hook domain. ESE-1 is abundantly expressed in human breast cancer and trans-activates epithelium-specific gene promoters in transient transfection assays. While it has been presumed that ETS factors transform mammary epithelial cells via their nuclear transcriptional functions, here we show (i) that ESE-1 protein is cytoplasmic in human breast cancer cells; (ii) that stably expressed green fluorescent protein-ESE-1 transforms MCF-12A human mammary epithelial cells; and (iii) that the ESE-1 SAR domain, acting in the cytoplasm, is necessary and sufficient to mediate this transformation. Deletion of transcriptional regulatory or nuclear localization domains does not impair ESE-1-mediated transformation, whereas fusing the simian virus 40 T-antigen nuclear localization signal to various ESE-1 constructs, including the SAR domain alone, inhibits their transforming capacity. Finally, we show that the nuclear localization of ESE-1 protein induces apoptosis in nontransformed mammary epithelial cells via a transcription-dependent mechanism. Together, our studies reveal two distinct ESE-1 functions, apoptosis and transformation, where the ESE-1 transcription activation domain contributes to apoptosis and the SAR domain mediates transformation via a novel nonnuclear, nontranscriptional mechanism. These studies not only describe a unique ETS factor transformation mechanism but also establish a new paradigm for cell transformation in general.

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Hypertonicity-induced phosphorylation and nuclear localization of the transcription factor TonEBP

AJP Cell Physiology ◽

10.1152/ajpcell.2001.280.2.c248 ◽

2001 ◽

Vol 280 (2) ◽

pp. C248-C253 ◽

Cited By ~ 90

Author(s):

Stephen C. Dahl ◽

Joseph S. Handler ◽

H. Moo Kwon

Keyword(s):

Transcription Factor ◽

Nuclear Localization ◽

Kinase Inhibitors ◽

Dependent Manner ◽

Binding Assays ◽

P38 Inhibitor ◽

Vitro Binding ◽

Compatible Osmolytes

The accumulation of compatible osmolytes during osmotic stress is observed in virtually all organisms. In mammals, the hypertonicity-induced expression of osmolyte transporters and synthetic enzymes is conferred by the presence of upstream tonicity-responsive enhancer (TonE) sequences. Recently, we described the cloning and initial characterization of TonE-binding protein (TonEBP), a transcription factor that translocates to the nucleus and associates with TonE sequences in a tonicity-dependent manner. We now report that hypertonicity induces an increase in TonEBP phosphorylation that temporally correlates with increased nuclear localization of the molecule. TonEBP phosphorylation is not affected by a number of kinase inhibitors, including the p38 inhibitor SB-203580. In addition, in vitro binding assays show that the association of TonEBP with TonE sequences is not affected by phosphorylation. Thus TonEBP phosphorylation is an early step in the response of cells to hypertonicity and may be required for nuclear import or retention.

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The nuclear localization of the Arabidopsis transcription factor TIP is blocked by its interaction with the coat protein of Turnip crinkle virus

Virology ◽

10.1016/j.virol.2004.10.039 ◽

2005 ◽

Vol 331 (2) ◽

pp. 316-324 ◽

Cited By ~ 46

Author(s):

Tao Ren ◽

Feng Qu ◽

T. Jack Morris

Keyword(s):

Transcription Factor ◽

Coat Protein ◽

Nuclear Localization ◽

Turnip Crinkle Virus

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Identification of a nuclear localization signal, RRMKWKK, in the homeodomain transcription factor PDX-1

FEBS Letters ◽

10.1016/s0014-5793(99)01446-5 ◽

1999 ◽

Vol 461 (3) ◽

pp. 229-234 ◽

Cited By ~ 62

Author(s):

Tilo Moede ◽

Barbara Leibiger ◽

Hamedeh Ghanaat Pour ◽

Per-Olof Berggren ◽

Ingo B Leibiger

Keyword(s):

Transcription Factor ◽

Nuclear Localization ◽

Nuclear Localization Signal ◽

Homeodomain Transcription Factor ◽

Localization Signal

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SUBCELLULAR LOCALIZATION OF FoxP3 TRANSCRIPTION FACTOR IN PATIENTS WITH ACUTE CORONARY SYNDROME: COMPARATIVE ANALYSIS AND PROSPECTIVE OBSERVATION

Medical Immunology (Russia) ◽

10.15789/1563-0625-slo-2226 ◽

2021 ◽

Vol 23 (4) ◽

pp. 731-736

Author(s):

I. V. Kologrivova ◽

Tatiana E. Suslova ◽

V. V. Ryabov ◽

M. A. Shtatolkina ◽

O. A. Koshelskaya ◽

...

Keyword(s):

Myocardial Infarction ◽

Acute Myocardial Infarction ◽

Transcription Factor ◽

T Lymphocytes ◽

Subcellular Localization ◽

Nuclear Localization ◽

Mononuclear Cells ◽

Nuclear Translocation ◽

Coronary Syndrome ◽

Treg Lymphocytes

The key cellular and molecular factors being involved in the resolution of inflammation following acute myocardial infarction remain poorly understood. T-regulatory (Treg) lymphocytes are characterized by the extreme potential to regulate the strength and direction of immune responses during the myocardial injury. The functional activity of Treg-lymphocytes depends upon the transcription factor forkhead box protein P3 (FoxP3). It may be also expressed in conventional T-lymphocytes at the stage of their activation. Nuclear localization of FoxP3 is a prerequisite factor determining its ability to impact the suppressive functions of Treglymphocytes.The aim of the present study was comparative evaluation of FoxP3+T-lymphocytes frequency and counts, combined with estimation of FoxP3 subcellular localization, in patients with acute myocardial infarction and chronic coronary syndrome and examination of changes of these parameters in the short-term follow-up of patients with myocardial infarction. The study included 14 patients with chronic coronary syndrome (8 males; 6 females; 63.2±9.0 y.o.) and 5 patients with acute anterior ST-segment elevation myocardial infarction (4 males; 1 female; 61.4±11.2 y.o.) at days 1, 3 and 7 after the event. The frequency of FoxP3+ conventional and regulatory T-lymphocytes was evaluated in peripheral blood mononuclear cells together with estimation of the level of FoxP3 nuclear localization by imaging flow cytometry.Patients with infarction were characterized by the decreased counts of FoxP3+Treg-lymphocytes compared to patients with chronic coronary syndrome, and exhibited even further decrease in the counts of FoxP3+Tregcells at day 7 after infarction, while frequency of Treg and conventional T-lymphocytes did not differ significantly. The level of FoxP3 nuclear translocation was lower both in Treg and conventional T-lymphocytes in patients at day 1 post-infarction compared to patients with chronic coronary syndrome. Absolute counts of FoxP3+Tregs with nuclear FoxP3 localization remained significantly lower both at days 1 and 7 post-infarction compared to patients with chronic coronary syndrome.Thus, here we demonstrated that FoxP3 nuclear localization experiences decrease in the course of acute myocardial infarction and may serve as a more sensitive marker of changes in Treg-lymphocyte functioning than simple evaluation of their frequency.

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Hydration Status Affects Nuclear Distribution of Transcription Factor Tonicity Responsive Enhancer Binding Protein in Rat Kidney

Journal of the American Society of Nephrology ◽

10.1681/asn.v12112221 ◽

2001 ◽

Vol 12 (11) ◽

pp. 2221-2230 ◽

Cited By ~ 3

Author(s):

JUNG H. CHA ◽

SEUNG KYOON WOO ◽

KI H. HAN ◽

YOUNG H. KIM ◽

JOSEPH S. HANDLER ◽

...

Keyword(s):

Transcription Factor ◽

Mrna Expression ◽

Nuclear Localization ◽

Binding Protein ◽

Renal Medulla ◽

Urine Osmolality ◽

Hydration Status ◽

Water Loading ◽

Nuclear Distribution ◽

Enhancer Binding Protein

Abstract. Tonicity responsive enhancer binding protein (TonEBP) is the transcription factor that regulates tonicity responsive expression of proteins that catalyze cellular accumulation of compatible osmolytes. In cultured MDCK cells, hypertonicity stimulates the activity of TonEBP via a combination of increased protein abundance and increased nuclear localization. For investigating regulation of TonEBP in the kidney, rats were subjected to water loading or dehydration. Water loading lowered urine osmolality and mRNA expression of sodium/myo-inositol cotransporter (SMIT), a target gene of TonEBP, in the renal medulla; dehydration doubled the urine osmolality and increased SMIT mRNA expression. In contrast, overall abundance of TonEBP and its mRNA measured by immunoblot and ribonuclease protection assay, respectively, was not affected. Immunohistochemical analysis, however, revealed that nuclear distribution of TonEBP is generally increased throughout the medulla in dehydrated animals compared with water loaded animals. Increased nuclear localization was particularly dramatic in thin limbs. Notable exceptions were the middle to terminal portions of the inner medullary collecting ducts and blood vessels, where a change in TonEBP distribution was not evident. Immunohistochemical detection of SMIT mRNA revealed that the changes in nuclear distribution of TonEBP correlate with expression of SMIT. It is concluded that under physiologic conditions, nucleocytoplasmic distribution is the dominant mode of regulation of TonEBP in the renal medulla.

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The C-terminal domain of Salmonid Alphavirus nonstructural protein 2 (nsP2) is essential and sufficient to block RIG-I pathway induction and interferon-mediated antiviral response.

Journal of Virology ◽

10.1128/jvi.01155-21 ◽

2021 ◽

Author(s):

Raphaël Jami ◽

Emilie Mérour ◽

Julie Bernard ◽

Annie Lamoureux ◽

Jean K. Millet ◽

...

Keyword(s):

Immune Response ◽

Immune System ◽

Innate Immune Response ◽

Nuclear Localization ◽

Innate Immune ◽

Type I ◽

Annual Growth Rate ◽

Structural Protein ◽

Terminal Domain ◽

Nuclear Localization Sequences

Salmonid alphavirus (SAV) is an atypical alphavirus, which has a considerable impact on salmon and trout farms. Unlike other alphaviruses such as the chikungunya virus, SAV is transmitted without an arthropod vector, and does not cause cell shut-off during infection. The mechanisms by which SAV escapes the host immune system remain unknown. By studying the role of SAV proteins on the RIG-I signaling cascade, the first line of defense of the immune system during infection, we demonstrated that non-structural protein 2 (nsP2) effectively blocks the induction of type I interferon (IFN). This inhibition, independent of the protease activity carried by nsP2, occurs downstream of IRF3 which is the transcription factor allowing the activation of the IFN promoter and its expression. The inhibitory effect of nsP2 on the RIG-I pathway depends on the localization of nsP2 in the host cell nucleus which is linked to two nuclear localization sequences (NLS) located in its C-terminal part. The C-terminal domain of nsP2 by itself is sufficient and necessary to block IFN induction. Mutation of the NLS of nsP2 is deleterious to the virus. Finally, nsP2 does not interact with IRF3, indicating that its action is possible through a targeted interaction within discrete areas of chromatin, as suggested by its punctate distribution observed in the nucleus. These results therefore demonstrate a major role for nsP2 in the control by SAV of the host cell’s innate immune response. Importance The global consumption of fish continues to rise and the future demand cannot be met by capture fisheries alone due to limited stocks of wild fish. Aquaculture is currently the world’s fastest growing food production sector with an annual growth rate of 6-8 %. Recurrent outbreaks of SAV result in significant economic losses with serious environmental consequences on wild stocks. While the clinical and pathological signs of SAV infection are fairly well known, the molecular mechanisms involved are poorly described. In the present study, we focus on the non-structural protein nsP2 and characterize a specific domain containing nuclear localization sequences that are critical for the inhibition of the host innate immune response mediated by the RIG-I pathway.

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Xenopus nuclear factor 7 (xnf7) possesses an NLS that functions efficiently in both oocytes and embryos

Journal of Cell Science ◽

10.1242/jcs.105.2.389 ◽

1993 ◽

Vol 105 (2) ◽

pp. 389-395

Author(s):

X. Li ◽

L.D. Etkin

Keyword(s):

Transcription Factor ◽

Zinc Finger ◽

Nuclear Localization ◽

Nuclear Localization Signal ◽

Nuclear Accumulation ◽

Nuclear Factor ◽

Zinc Finger Gene ◽

Early Embryos ◽

Localization Signal ◽

Nuclear Phosphoprotein

Xenopus nuclear factor 7 (xnf7) is a nuclear phosphoprotein that is encoded by a member of a novel zinc finger gene family and likely functions as a transcription factor. It possesses a nuclear localization signal (NLS) similar to the bipartite basic NLS of nucleoplasmin, but unlike nucleoplasmin, which re-enters nuclei immediately after fertilization, xnf7 remains cytoplasmic until the mid-blastula transition (MBT). We have measured the accumulation of injected labeled xnf7 protein or protein produced from synthetic xnf7 transcripts in the oocyte nuclei (GV). The data show that the NLS of xnf7 functions efficiently in oocytes. Mutations in either of the bipartite basic domains of the xnf7 NLS inhibit nuclear accumulation, while mutations in the spacer sequences have no effect. The xnf7 NLS linked to pyruvate kinase directs the efficient accumulation of this protein into nuclei of early embryos prior to the MBT. These data suggest that retention of the xnf7 protein during development is the result of a mechanism that interferes with the xnf7 NLS function.

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