scholarly journals PP2A Regulates HDAC4 Nuclear Import

2008 ◽  
Vol 19 (2) ◽  
pp. 655-667 ◽  
Author(s):  
Gabriela Paroni ◽  
Nadia Cernotta ◽  
Claudio Dello Russo ◽  
Paola Gallinari ◽  
Michele Pallaoro ◽  
...  
Keyword(s):  
Nuclear Import ◽  
Nuclear Export ◽  
Histone Deacetylases ◽  
Phosphorylation Site ◽  
Class Ii ◽  
Binding Studies ◽  
Nuclear Entry ◽  
Putative Phosphorylation Site

Different signal-regulated serine/threonine kinases phosphorylate class II histone deacetylases (HDACs) to promote nuclear export, cytosolic accumulation, and activation of gene transcription. However, little is known about mechanisms operating in the opposite direction, which, possibly through phosphatases, should promote class II HDACs nuclear entry and subsequent gene repression. Here we show that HDAC4 forms a complex with the PP2A holoenzyme Cα, Aα, B/PR55α. In vitro and in vivo binding studies demonstrate that the N-terminus of HDAC4 interacts with the catalytic subunit of PP2A. HDAC4 is dephosphorylated by PP2A and experiments using okadaic acid or RNA interference have revealed that PP2A controls HDAC4 nuclear import. Moreover, we identified serine 298 as a putative phosphorylation site important for HDAC4 nuclear import. The HDAC4 mutant mimicking phosphorylation of serine 298 is defective in nuclear import. Mutation of serine 298 to alanine partially rescues the defect in HDAC4 nuclear import observed in cells with down-regulated PP2A. These observations suggest that PP2A, via the dephosphorylation of multiple serines including the 14-3-3 binding sites and serine 298, controls HDAC4 nuclear import.

scholarly journals Nuclear Import of IκBα Is Accomplished by a Ran-Independent Transport Pathway

2000 ◽  
Vol 20 (5) ◽  
pp. 1571-1582 ◽  
Author(s):  
Shrikesh Sachdev ◽  
Sriparna Bagchi ◽  
Donna D. Zhang ◽  
Angela C. Mings ◽  
Mark Hannink
Keyword(s):  
Nuclear Import ◽  
Nuclear Export ◽  
Dominant Negative ◽  
Dominant Negative Mutant ◽  
Nuclear Pore ◽  
Transport Pathway ◽  
Repeat Domain ◽  
Nuclear Export Receptor

ABSTRACT The inhibitor of kappa B alpha (IκBα) protein is able to shuttle between the cytoplasm and the nucleus. We have utilized a combination of in vivo and in vitro approaches to provide mechanistic insight into nucleocytoplasmic shuttling by IκBα. IκBα contains multiple functional domains that contribute to shuttling of IκBα between the cytoplasm and the nucleus. Nuclear import of IκBα is mediated by the central ankyrin repeat domain. Similar to previously described nuclear import pathways, nuclear import of IκBα is temperature and ATP dependent and is blocked by a dominant-negative mutant of importin β. However, in contrast to classical nuclear import pathways, nuclear import of IκBα is independent of soluble cytosolic factors and is not blocked by the dominant-negative RanQ69L protein. Nuclear export of IκBα is mediated by an N-terminal nuclear export sequence. Nuclear export of IκBα requires the CRM1 nuclear export receptor and is blocked by the dominant-negative RanQ69L protein. Our results are consistent with a model in which nuclear import of IκBα is mediated through direct interactions with components of the nuclear pore complex, while nuclear export of IκBα is mediated via a CRM1-dependent pathway.

Abstract 283: Redox-mediated Regulation of Histone deacetylase4, a Class II HDAC, by Thioredoxin1 through Interaction with DnaJb5, a Heat Shock Protein 40

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Tetsuro Ago ◽  
Tong Liu ◽  
Hong Li ◽  
Jeffery Molkentin ◽  
Junichi Sadoshima
Keyword(s):  
Heat Shock ◽  
Heat Shock Protein ◽  
Cardiac Hypertrophy ◽  
Nuclear Localization ◽  
Nuclear Export ◽  
Pressure Overload ◽  
Class Ii ◽  
Luciferase Reporter

Thioredoxin1 (Trx1) reduces redox-sensitive proteins and regulates cell growth and death. We previously reported that cardiac hypertrophy induced by pressure-overload is suppressed in mice with cardiac specific overexpression of Trx1 (Tg-Trx1). To elucidate the mechanisms by which Trx1 suppresses cardiac hypertrophy, we performed DNA microarray analysis using Tg-Trx1 mouse hearts. We identified DnaJb5, a heat shock protein 40, as a gene significantly upregulated by Trx1. Immunostaining and immunoblot analyses indicated that Trx1 and DnaJb5 are co-localized in the nucleus of myocytes. Pull-down and immunoprecipitation assays showed that DnaJb5 interacts with TBP-2, a Trx1-binding protein. DnaJb5 did not disturb the interaction between Trx1 and TBP-2, and enhanced the Trx1 reducing activity. Both Trx1 and DnaJb5 attenuated phenylephrine (PE)-induced activation of NFAT and myocyte hypertrophy in vitro . Using transgenic mice harboring an NFAT luciferase reporter, we confirmed that Trx1 suppresses both NFAT activation and cardiac hypertrophy induced by PE in vivo . We also found that DnaJb5 binds directly to histone deacetylase 4 (HDAC4), a class II HDAC. An HDAC4 mutant lacking the minimal region responsible for the interaction with DnaJb5 (residues 628 – 881) was localized in the cytosol, in contrast to the nuclear localization of the wild-type HDAC4, suggesting the importance of the interaction for the nuclear localization of HDAC4. Overexpression of Trx1 suppressed PE-induced nuclear export of HDAC4 in myocytes. Using mass spectroscopy, we found that HDAC4 forms a disulfide bond between Cys-667 and -669, which was reduced by Trx1. The HDAC4 Cys667/669Ser mutant was localized in the cytosol, and its nuclear export was suppressed by leptomycin B, an inhibitor of exportin, suggesting that the redox modification induces nuclear export regardless of phosphorylation. Consistently, the Cys667/669Ser substitution abolished the suppressive effect of HDAC4 on NFAT activity and cardiac hypertrophy. Collectively, these results show that Trx1 upregulates DnaJb5, which recruits HDAC4 into the complex formed by Trx1-TBP-2-DnaJb5, thereby reducing HDAC4, retaining its nuclear localization, and suppressing NFAT activity and cardiac hypertrophy.

scholarly journals Intestinal Cell Kinase (ICK) Promotes Activation of mTOR Complex 1 (mTORC1) through Phosphorylation of Raptor Thr-908

2012 ◽  
Vol 287 (15) ◽  
pp. 12510-12519 ◽  
Author(s):  
Di Wu ◽  
Jessica R. Chapman ◽  
Lifu Wang ◽  
Thurl E. Harris ◽  
Jeffrey Shabanowitz ◽  
...  
Keyword(s):  
Cell Proliferation ◽  
Consensus Sequence ◽  
Phosphorylation Site ◽  
Intestinal Cell ◽  
Putative Phosphorylation Site ◽  
Mtorc1 Signaling ◽  
Mtor Complex 1 ◽  
Intestinal Cell Kinase

Intestinal cell kinase (ICK), named after its cloning origin, the intestine, is actually a ubiquitously expressed and highly conserved serine/threonine protein kinase. Recently we reported that ICK supports cell proliferation and G1 cell cycle progression. ICK deficiency significantly disrupted the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) signaling events. However, the biological substrates that mediate the downstream signaling effects of ICK in proliferation and the molecular mechanisms by which ICK interacts with mTORC1 are not well defined. Our prior studies also provided biochemical evidence that ICK interacts with the mTOR/Raptor complex in cells and phosphorylates Raptor in vitro. In this report, we investigated whether and how ICK targets Raptor to regulate the activity of mTORC1. Using the ICK substrate consensus sequence [R-P-X-S/T-P/A/T/S], we identified a putative phosphorylation site, RPGT908T, for ICK in human Raptor. By mass spectrometry and a phospho-specific antibody, we showed that Raptor Thr-908 is a novel in vivo phosphorylation site. ICK is able to phosphorylate Raptor Thr-908 both in vitro and in vivo and when Raptor exists in protein complexes with or without mTOR. Although expression of the Raptor T908A mutant did not affect the mTORC1 integrity, it markedly impaired the mTORC1 activation by insulin or by overexpression of the small GTP-binding protein RheB under nutrient starvation. Our findings demonstrate an important role for ICK in modulating the activity of mTORC1 through phosphorylation of Raptor Thr-908 and thus implicate a potential signaling mechanism by which ICK regulates cell proliferation and division.

scholarly journals Clb6/Cdc28 and Cdc14 Regulate Phosphorylation Status and Cellular Localization of Swi6

2004 ◽  
Vol 24 (6) ◽  
pp. 2277-2285 ◽  
Author(s):  
Marco Geymonat ◽  
Ad Spanos ◽  
Glenn P. Wells ◽  
Stephen J. Smerdon ◽  
Steven G. Sedgwick
Keyword(s):  
Cell Cycle ◽  
Nuclear Import ◽  
Nuclear Export ◽  
Cellular Localization ◽  
Entry And Exit ◽  
Mitotic Exit Network ◽  
M Phase ◽  
Cdc28 Kinase

ABSTRACT Nuclear export of the transcription factor Swi6 during the budding yeast Saccharomyces cerevisiae cell cycle is known to require phosphorylation of the Swi6 serine 160 residue. We show that Clb6/Cdc28 kinase is required for this nuclear export. Furthermore, Cdc28 combined with the S-phase cyclin Clb6 specifically phosphorylates serine 160 of Swi6 in vitro. Nuclear import of Swi6 occurs concomitantly with dephosphorylation of serine 160 in late M phase. We show that Cdc14 phosphatase, the principal effector of the mitotic exit network, can trigger nuclear import of Swi6 in vivo and that Cdc14 dephosphorylates Swi6 at serine 160 in vitro. Taken together, these observations show how Swi6 dephosphorylation and phosphorylation are integrated into changes of Cdc28 activity governing entry and exit from the G1 phase of the cell cycle.

Inhibition of both class I and class II histone deacetylases is required to effectively inhibit osteoclast bone resorption in vivo and in vitro

Bone ◽  
2009 ◽  
Vol 44 ◽  
pp. S133-S134
Author(s):  
M.D. Cantley ◽  
D.P. Fairlie ◽  
M.P. Bartold ◽  
K.D. Rainsford ◽  
D.R. Haynes
Keyword(s):  
Bone Resorption ◽  
Histone Deacetylases ◽  
Class Ii ◽  
Class I

Cruciferous Vegetables as Antioxidative, Chemopreventive and Antineoplasic Functional Foods: Preclinical and Clinical Evidences of Sulforaphane Against Prostate Cancers

2019 ◽  
Vol 24 (40) ◽  
pp. 4779-4793 ◽  
Author(s):  
Paulo M.P. Ferreira ◽  
Lays A.R.L. Rodrigues ◽  
Lunna Paula de Alencar Carnib ◽  
Paulo Víctor de Lima Sousa ◽  
Luis Michel Nolasco Lugo ◽  
...  
Keyword(s):  
Histone Deacetylases ◽  
Cruciferous Vegetables ◽  
Tumor Cell Death ◽  
Antitumor Effects ◽  
Antiapoptotic Proteins ◽  
Cycle Arrest ◽  
Government Documents ◽  
Prostate Cancers

Background: Sulforaphane (SF, 1-isothiocyanato-4-(methyl-sulfinyl)-butane) is found in broccoli, cabbage and cauliflower. Methods: we performed a critical review on the antioxidative, chemopreventive and antitumor effects of SF from cruciferous vegetables against prostate cancers and molecular pathways. For a complete and reliable review, primary and secondary resources were used, including original and review articles, books and government documents published until March 2018. Articles that are in duplicity and disconnected are not considered for review. SF is derived from glucoraphanin (4-methyl-sulfinyl-butyl-glucosinate), being one of the most commonly found isothiocyanates in vegetables from Brassica spp., especially in broccoli samples. In vitro studies indicate that SF induces apoptosis in a dependent or non-dependent method of androgens by transcription of tumor suppressor genes, oxidation response and higher expression of phase II enzymes in prostate cancer cells. Sulforaphane also decreases transcription of the nuclear factor kB and antiapoptotic proteins, expression of cyclin D2 and survivin and DNA synthesis, increases Nrf2 gene activity, interferes with genome compacting by inhibition of histone deacetylases and disrupts Hsp90 complexes, which cause cell cycle arrest, mitosis interruption, activation of caspases and mitochondria depolarization. Conclusion: SF and cruciferous vegetables play antioxidative and chemopreventive role, delaying or blocking in vivo carcinogenesis, causing biochemical and epigenetic changes, preventing, delaying, or reversing preneoplastic or advanced prostate lesions, and frequently activating tumor cell death by intrinsic methods of apoptosis. These outcomes encourage the consumption of Brassica specimens, which could be easily achieved by the incorporation of food and vegetables rich in cruciferous isothiocyanates in the diet.

Chemosensitizing Activity of Histone Deacetylases Inhibitory Cyclic Hydroxamic Acids for Combination Chemotherapy of Lymphatic Leukemia

2018 ◽  
Vol 18 (4) ◽  
pp. 365-371 ◽  
Author(s):  
Denis V. Mishchenko ◽  
Margarita E. Neganova ◽  
Elena N. Klimanova ◽  
Tatyana E. Sashenkova ◽  
Sergey G. Klochkov ◽  
...  
Keyword(s):  
Lipid Peroxidation ◽  
Acute Toxicity ◽  
Histone Deacetylases ◽  
Hydroxamic Acids ◽  
Water Soluble ◽  
Male Rat ◽  
Hybrid Male ◽  
Cyclic Hydroxamic Acids

Background: Anti-tumor effect of hydroxamic acid derivatives is largely connected with its properties as efficient inhibitors of histone deacetylases, and other metalloenzymes involved in carcinogenesis. Objective: The work was aimed to (i) determine the anti-tumor and chemosensitizing activity of the novel racemic spirocyclic hydroxamic acids using experimental drug sensitive leukemia P388 of mice, and (ii) determine the structure-activity relationships as metal chelating and HDAC inhibitory agents. Method: Outbreed male rat of 200-220 g weights were used in biochemical experiments. In vivo experiments were performed using the BDF1 hybrid male mice of 22-24 g weight. Lipid peroxidation, Fe (II) -chelating activity, HDAC fluorescent activity, anti-tumor and anti-metastatic activity, acute toxicity techniques were used in this study. Results: Chemosensitizing properties of water soluble cyclic hydroxamic acids (CHA) are evaluated using in vitro activities and in vivo methods and found significant results. These compounds possess iron (II) chelating properties, and slightly inhibit lipid peroxidation. CHA prepared from triacetonamine (1a-e) are more effective Fe (II) ions cheaters, as compared to CHA prepared from 1- methylpiperidone (2a-e). The histone deacetylase (HDAC) inhibitory activity, lipophilicity and acute toxicity were influenced by the length amino acids (size) (Glycine < Alanine < Valine < Leucine < Phenylalanine). All compounds bearing spiro-N-methylpiperidine ring (2a-e) are non-toxic up to 1250 mg/kg dose, while compounds bearing spiro-tetramethylpiperidine ring (1a-e) exhibit moderate toxicity which increases with increasing lipophility, but not excite at 400 mg/kg. Conclusion: It was shown that the use of combination of non-toxic doses of cisplatin (cPt) or cyclophosphamide with CHA in most cases result in the appearance of a considerable anti-tumor effect of cytostatics. The highest chemosensitizing activity with respect to leukemia Р388 is demonstrated by the CHA derivatives of Valine 1c or 2c.

scholarly journals HDAC4 promotes nasopharyngeal carcinoma progression and serves as a therapeutic target

2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Chun Cheng ◽  
Jun Yang ◽  
Si-Wei Li ◽  
Guofu Huang ◽  
Chenxi Li ◽  
...  
Keyword(s):  
Nasopharyngeal Carcinoma ◽  
Tumor Growth ◽  
Therapeutic Target ◽  
Histone Deacetylases ◽  
Migration And Invasion ◽  
Poor Overall Survival ◽  
Mesenchymal Transition ◽  
E Cadherin

AbstractHistone deacetylases (HDACs) are involved in tumor progression, and some have been successfully targeted for cancer therapy. The expression of histone deacetylase 4 (HDAC4), a class IIa HDAC, was upregulated in our previous microarray screen. However, the role of HDAC4 dysregulation and mechanisms underlying tumor growth and metastasis in nasopharyngeal carcinoma (NPC) remain elusive. Here, we first confirmed that the HDAC4 levels in primary and metastatic NPC tissues were significantly increased compared with those in normal nasopharyngeal epithelial tissues and found that high HDAC4 expression predicted a poor overall survival (OS) and progression-free survival (PFS). Functionally, HDAC4 accelerated cell cycle G1/S transition and induced the epithelial-to-mesenchymal transition to promote NPC cell proliferation, migration, and invasion in vitro, as well as tumor growth and lung metastasis in vivo. Intriguingly, knockdown of N-CoR abolished the effects of HDAC4 on the invasion and migration abilities of NPC cells. Mechanistically, HDAC3/4 binds to the E-cadherin promoter to repress E-cadherin transcription. We also showed that the HDAC4 inhibitor tasquinimod suppresses tumor growth in NPC. Thus, HDAC4 may be a potential diagnostic marker and therapeutic target in patients with NPC.

Improved Bioavailability of Oxcarbazepine, a BCS class II drug by Centrifugal Melt Spinning: In-vitro and in-vivo Implications

2021 ◽  
pp. 120775
Author(s):  
Sidra Nasir ◽  
Amjad Hussain ◽  
Nasir Abbas ◽  
Nadeem Irfan Bukhari ◽  
Fahad Hussain ◽  
...  
Keyword(s):  
Melt Spinning ◽  
Class Ii ◽  
Bcs Class Ii

scholarly journals Localization matters: nuclear-trapped Survivin sensitizes glioblastoma cells to temozolomide by elevating cellular senescence and impairing homologous recombination

2021 ◽  
Author(s):  
Thomas R. Reich ◽  
Christian Schwarzenbach ◽  
Juliana Brandstetter Vilar ◽  
Sven Unger ◽  
Fabian Mühlhäusler ◽  
...  
Keyword(s):  
Homologous Recombination ◽  
Nuclear Export ◽  
Cell Model ◽  
Chromosome Instability ◽  
Direct Interaction ◽  
High Grade Glioma ◽  
Strand Break ◽  
Γh2ax Foci

AbstractTo clarify whether differential compartmentalization of Survivin impacts temozolomide (TMZ)-triggered end points, we established a well-defined glioblastoma cell model in vitro (LN229 and A172) and in vivo, distinguishing between its nuclear and cytoplasmic localization. Expression of nuclear export sequence (NES)-mutated Survivin (SurvNESmut-GFP) led to impaired colony formation upon TMZ. This was not due to enhanced cell death but rather due to increased senescence. Nuclear-trapped Survivin reduced homologous recombination (HR)-mediated double-strand break (DSB) repair, as evaluated by γH2AX foci formation and qPCR-based HR assay leading to pronounced induction of chromosome aberrations. Opposite, clones, expressing free-shuttling cytoplasmic but not nuclear-trapped Survivin, could repair TMZ-induced DSBs and evaded senescence. Mass spectrometry-based interactomics revealed, however, no direct interaction of Survivin with any of the repair factors. The improved TMZ-triggered HR activity in Surv-GFP was associated with enhanced mRNA and stabilized RAD51 protein expression, opposite to diminished RAD51 expression in SurvNESmut cells. Notably, cytoplasmic Survivin could significantly compensate for the viability under RAD51 knockdown. Differential Survivin localization also resulted in distinctive TMZ-triggered transcriptional pathways, associated with senescence and chromosome instability as shown by global transcriptome analysis. Orthotopic LN229 xenografts, expressing SurvNESmut exhibited diminished growth and increased DNA damage upon TMZ, as manifested by PCNA and γH2AX foci expression, respectively, in brain tissue sections. Consequently, those mice lived longer. Although tumors of high-grade glioma patients expressed majorly nuclear Survivin, they exhibited rarely NES mutations which did not correlate with survival. Based on our in vitro and xenograft data, Survivin nuclear trapping would facilitate glioma response to TMZ.

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