One of the key features of eukaryotic cells is the separation of nuclear and cytoplasmic compartments by a double-layer nuclear envelope. This separation is crucial for timely regulation of gene expression, mRNA biogenesis, cell cycle, and differentiation. Since transcription takes place in the nucleus and the major part of translation in the cytoplasm, proper distribution of biomolecules between these two compartments is ensured by nucleocytoplasmic shuttling proteins - karyopherins. Karyopherins transport biomolecules through nuclear pores bidirectionally in collaboration with Ran GTPases and utilize GTP as the source of energy. Different karyopherins transport different cargo molecules that play important roles in the regulation of cell physiology. In cancer cells, this nucleocytoplasmic transport is significantly dysregulated to support increased demands for the import of cell cycle-promoting biomolecules and export of cell cycle inhibitors and mRNAs. Here, we analysed genomic, transcriptomic and proteomic data from published datasets to comprehensively profile karyopherin genes in hepatocellular carcinoma. We have found out that expression of multiple karyopherin genes is increased in hepatocellular carcinoma in comparison to the normal liver, with importin subunit α-1, exportin 2, importin subunit β-1 and importin 9 being the most over-expressed. More-over, we have found that increased expression of these genes is associated with higher neoplasm grade as well as significantly worse overall survival of liver cancer patients. Taken together, our bioinformatic data-mining analysis provides a comprehensive geno-mic and transcriptomic landscape of karyopherins in hepatocellular carcinoma and identifies potential members that could be targeted in order to develop new treatment regimens.

• Klíčová slova
• cancer, hepatocellular carcinoma, karyopherin, molecular profiling, nucleocytoplasmic transport,
• MeSH
• aktivní transport - buněčné jádro MeSH
• buněčné jádro metabolismus   MeSH
• hepatocelulární karcinom * genetika   metabolismus   MeSH
• karyoferiny genetika   metabolismus   MeSH
• lidé MeSH
• nádory jater * genetika   metabolismus   MeSH
• prognóza MeSH
• proteomika MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• karyoferiny MeSH

OBJECTIVE: Hereditary spastic paraplegia (HSP) is a highly heterogeneous neurologic disorder characterized by lower-extremity spasticity. Here, we set out to determine the genetic basis of an autosomal dominant, pure, and infantile-onset form of HSP in a cohort of 8 patients with a uniform clinical presentation. METHODS: Trio whole-exome sequencing was used in 5 index patients with infantile-onset pure HSP to determine the genetic cause of disease. The functional impact of identified genetic variants was verified using bioinformatics and complementary cellular and biochemical assays. RESULTS: Distinct heterozygous KPNA3 missense variants were found to segregate with the clinical phenotype in 8 patients; in 4 of them KPNA3 variants had occurred de novo. Mutant karyopherin-α3 proteins exhibited a variable pattern of altered expression level, subcellular distribution, and protein interaction. INTERPRETATION: Our genetic findings implicate heterozygous variants in KPNA3 as a novel cause for autosomal dominant, early-onset, and pure HSP. Mutant karyopherin-α3 proteins display varying deficits in molecular and cellular functions, thus, for the first time, implicating dysfunctional nucleocytoplasmic shuttling as a novel pathomechanism causing HSP. ANN NEUROL 2021;90:738-750.

• MeSH
• alfa karyoferiny genetika   MeSH
• dospělí MeSH
• fenotyp MeSH
• heterozygot MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mutace genetika   MeSH
• předškolní dítě MeSH
• rodokmen MeSH
• sekvenování exomu metody   MeSH
• spastická paraplegie dědičná genetika   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• alfa karyoferiny MeSH
• KPNA3 protein, human MeSH Prohlížeč

Exportin 1 (XPO1), also known as chromosome maintenance 1 protein (CRM1), is the main transporter for hundreds of proteins like tumor suppressors, growth regulatory factors, oncoprotein mRNAs and others. Its upregulation leads to the inactivation of the tumor suppressor anti-neoplastic function in many cancers and logically is associated with poor prognosis. Selective inhibitors of nuclear export (SINE) are a new generation of XPO1 inhibitors that are being investigated as a promising targeted anti-cancer therapy. Selinexor is the first generation of SINE compounds that is being evaluated in many clinical trials involving solid tumors and hematological malignancies with its two approved indications for relapsed multiple myeloma and relapsed diffuse large B-cell lymphoma. Here, we comprehensively review the current knowledge of selinexor and next generations of the SINE compounds in lymphoid and myeloid malignancies.

• Klíčová slova
• Exportin 1 protein, Leukemia, Lymphoma, Myeloma, Selective inhibitors of nuclear export, Selinexor,
• MeSH
• aktivní transport - buněčné jádro účinky léků   MeSH
• cílená molekulární terapie MeSH
• hematologické nádory diagnóza   farmakoterapie   etiologie   mortalita   MeSH
• hydraziny farmakologie   terapeutické užití   MeSH
• karyoferiny antagonisté a inhibitory   MeSH
• lidé MeSH
• management nemoci MeSH
• prognóza MeSH
• protein exportin 1 MeSH
• protinádorové látky farmakologie   terapeutické užití   MeSH
• receptory cytoplazmatické a nukleární antagonisté a inhibitory   MeSH
• triazoly farmakologie   terapeutické užití   MeSH
• výsledek terapie MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• hydraziny MeSH
• karyoferiny MeSH
• protinádorové látky MeSH
• receptory cytoplazmatické a nukleární MeSH
• selinexor MeSH Prohlížeč
• triazoly MeSH

Homologous chromosome segregation during meiosis I (MI) in mammalian oocytes is carried out by the acentrosomal MI spindles. Whereas studies in human oocytes identified Ran GTPase as a crucial regulator of the MI spindle function, experiments in mouse oocytes questioned the generality of this notion. Here, we use live-cell imaging with fluorescent probes and Förster resonance energy transfer (FRET) biosensors to monitor the changes in Ran and importin β signaling induced by perturbations of Ran in mouse oocytes while examining the MI spindle dynamics. We show that unlike RanT24N employed in previous studies, a RanT24N, T42A double mutant inhibits RanGEF without perturbing cargo binding to importin β and disrupts MI spindle function in chromosome segregation. Roles of Ran and importin β in the coalescence of microtubule organizing centers (MTOCs) and MI spindle assembly are further supported by the use of the chemical inhibitor importazole, whose effects are partially rescued by the GTP hydrolysis-resistant RanQ69L mutant. These results indicate that RanGTP is essential for MI spindle assembly and function both in humans and mice.

• Klíčová slova
• RanGTP, importazole, importin β, meiosis I, oocyte,
• MeSH
• aparát dělícího vřeténka fyziologie   MeSH
• beta karyoferiny genetika   metabolismus   MeSH
• jaderné proteiny genetika   metabolismus   MeSH
• meióza fyziologie   MeSH
• mikrotubuly metabolismus   MeSH
• mutace MeSH
• myši MeSH
• oocyty cytologie   metabolismus   MeSH
• proteiny buněčného cyklu genetika   metabolismus   MeSH
• Ran protein vázající GTP genetika   metabolismus   MeSH
• segregace chromozomů MeSH
• výměnné faktory guaninnukleotidů genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• ženské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• beta karyoferiny MeSH
• jaderné proteiny MeSH
• proteiny buněčného cyklu MeSH
• Ran protein vázající GTP MeSH
• Rcc1 protein, mouse MeSH Prohlížeč
• výměnné faktory guaninnukleotidů MeSH

Transfer RNAs (tRNAs) are central players in protein synthesis, which in Eukarya need to be delivered from the nucleus to the cytoplasm by specific transport receptors, most of which belong to the evolutionarily conserved beta-importin family. Based on the available literature, we identified two candidates, Xpo-t and Xpo-5 for tRNA export in Trypanosoma brucei. However, down-regulation of expression of these genes did not disrupt the export of tRNAs to the cytoplasm. In search of alternative pathways, we tested the mRNA export complex Mex67-Mtr2, for a role in tRNA nuclear export, as described previously in yeast. Down-regulation of either exporter affected the subcellular distribution of tRNAs. However, contrary to yeast, TbMex67 and TbMtr2 accumulated different subsets of tRNAs in the nucleus. While TbMtr2 perturbed the export of all the tRNAs tested, silencing of TbMex67, led to the nuclear accumulation of tRNAs that are typically modified with queuosine. In turn, inhibition of tRNA nuclear export also affected the levels of queuosine modification in tRNAs. Taken together, the results presented demonstrate the dynamic nature of tRNA trafficking in T. brucei and its potential impact not only on the availability of tRNAs for protein synthesis but also on their modification status.

• MeSH
• beta karyoferiny antagonisté a inhibitory   genetika   metabolismus   MeSH
• biologický transport MeSH
• buněčné jádro genetika   metabolismus   MeSH
• cytoplazma genetika   metabolismus   MeSH
• konformace nukleové kyseliny MeSH
• malá interferující RNA genetika   metabolismus   MeSH
• messenger RNA genetika   metabolismus   MeSH
• nukleocytoplazmatické transportní proteiny antagonisté a inhibitory   genetika   metabolismus   MeSH
• nukleosid Q chemie   metabolismus   MeSH
• proteosyntéza MeSH
• protozoální proteiny antagonisté a inhibitory   genetika   metabolismus   MeSH
• regulace genové exprese MeSH
• RNA protozoální chemie   genetika   metabolismus   MeSH
• RNA transferová chemie   genetika   metabolismus   MeSH
• signální transdukce MeSH
• Trypanosoma brucei brucei genetika   metabolismus   MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• beta karyoferiny MeSH
• malá interferující RNA MeSH
• messenger RNA MeSH
• nukleocytoplazmatické transportní proteiny MeSH
• nukleosid Q MeSH
• protozoální proteiny MeSH
• RNA protozoální MeSH
• RNA transferová MeSH

MicroRNAs (miRNAs) are small non-coding RNAs that post-transcriptionally regulate gene expression. Each step of their production and maturation has to be strictly regulated, as any disruption of control mechanisms may lead to cancer. Thus, we have measured the expression of 19 genes involved in miRNAs biogenesis pathway in tumor tissues of 239 colorectal cancer (CRC) patients, 17 CRC patients with liver metastases and 239 adjacent tissues using real-time PCR. Subsequently, the expression of analyzed genes was correlated with the clinical-pathological features as well as with the survival of patients. In total, significant over-expression of all analyzed genes was observed in tumor tissues as well as in liver metastases except for LIN28A/B. Furthermore, it was shown that the deregulated levels of some of the analyzed genes significantly correlate with tumor stage, grade, location, size and lymph node positivity. Finally, high levels of DROSHA and TARBP2 were associated with shorter disease-free survival, while the over-expression of XPO5, TNRC6A and DDX17 was detected in tissues of patients with shorter overall survival and poor prognosis. Our data indicate that changed levels of miRNA biogenesis genes may contribute to origin as well as progression of CRC; thus, these molecules could serve as potential therapeutic targets.

• Klíčová slova
• RT-qPCR, biogenesis, colorectal cancer, disease-free survival, microRNA, overall survival,
• MeSH
• biosyntetické dráhy genetika   MeSH
• dospělí MeSH
• Kaplanův-Meierův odhad MeSH
• karyoferiny genetika   MeSH
• kolorektální nádory genetika   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• mikro RNA genetika   MeSH
• nádory jater genetika   sekundární   MeSH
• prognóza MeSH
• regulace genové exprese u nádorů * MeSH
• ribonukleasa III genetika   MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• DROSHA protein, human MeSH Prohlížeč
• karyoferiny MeSH
• mikro RNA MeSH
• ribonukleasa III MeSH
• XPO5 protein, human MeSH Prohlížeč

Microtubules of all eukaryotic cells are formed by α- and β-tubulin heterodimers. In addition to the well known cytoplasmic tubulins, a subpopulation of tubulin can occur in the nucleus. So far, the potential function of nuclear tubulin has remained elusive. In this work, we show that α- and β-tubulins of various organisms contain multiple conserved nuclear export sequences, which are potential targets of the Exportin 1/CRM1 pathway. We demonstrate exemplarily that these NES motifs are sufficient to mediate export of GFP as model cargo and that this export can be inhibited by leptomycin B, an inhibitor of the Exportin 1/CRM1 pathway. Likewise, leptomycin B causes accumulation of GFP-tagged tubulin in interphase nuclei, in both plant and animal model cells. Our analysis of nuclear tubulin content supports the hypothesis that an important function of nuclear tubulin export is the exclusion of tubulin from interphase nuclei, after being trapped by nuclear envelope reassembly during telophase.

• MeSH
• aktivní transport - buněčné jádro fyziologie   MeSH
• buněčné jádro metabolismus   MeSH
• buněčné linie MeSH
• cytoplazma metabolismus   MeSH
• eukaryotické buňky metabolismus   MeSH
• karyoferiny metabolismus   MeSH
• lidé MeSH
• mikrotubuly metabolismus   MeSH
• protein exportin 1 MeSH
• receptory cytoplazmatické a nukleární metabolismus   MeSH
• tabák metabolismus   MeSH
• transport proteinů fyziologie   MeSH
• tubulin metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• karyoferiny MeSH
• receptory cytoplazmatické a nukleární MeSH
• tubulin MeSH

In search of novel targets for influenza inhibitors, a site on PB1 was selected for its high conservation and probable interaction with a host protein, RanBP5, that is key to nuclear import of PB1, where it complexes with PB2, PA, and NP to transcribe viral RNA. Docking with libraries of drug-like compounds led to a selection of five candidates that bound tightly and with a pose likely to inhibit protein binding. These were purchased and tested in vitro, found to be active, and then one was synthetically expanded to explore the structure-activity relationship. The top candidates had a carboxylic acid converted to an ester and electron-withdrawing substituents added to a phenyl group in the original structure. Resistance was slow to develop, but cytotoxicity was moderately high. Nuclear localization of PB1 and in vitro polymerase activity were both strongly inhibited.

• Klíčová slova
• Antiviral, Nuclear localization, Polymerase inhibition, Virtual screening,
• MeSH
• beta karyoferiny metabolismus   MeSH
• chřipka lidská farmakoterapie   MeSH
• lidé MeSH
• objevování léků MeSH
• počítačová simulace MeSH
• replikace viru účinky léků   MeSH
• rychlé screeningové testy MeSH
• simulace molekulového dockingu MeSH
• virové proteiny antagonisté a inhibitory   MeSH
• virus chřipky A účinky léků   enzymologie   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• beta karyoferiny MeSH
• influenza virus polymerase basic protein 1 MeSH Prohlížeč
• IPO5 protein, human MeSH Prohlížeč
• virové proteiny MeSH

BACKGROUND INFORMATION: Repair of damaged DNA is essential for maintaining genomic stability. TP53-binding protein 1 (53BP1) plays an important role in repair of the DNA double-strand breaks. Nuclear localisation of 53BP1 depends on importin β and nucleoporin 153, but the type and location of 53BP1 nuclear localisation signal (NLS) have yet to be determined. RESULTS: Here, we show that nuclear import of 53BP1 depends on two basic regions, namely 1667-KRK-1669 and 1681-KRGRK-1685, which are both needed for importin binding. Lysine 1667 is essential for interaction with importin and its substitution to arginine reduced nuclear localisation of 53BP1. Furthermore, we have found that CDK1-dependent phosphorylation of 53BP1 at S1678 impairs importin binding during mitosis. Phosphorylation-mimicking mutant S1678D showed reduced nuclear localisation, suggesting that phosphorylation of the NLS interferes with nuclear import of the 53BP1 CONCLUSIONS: We show that 53BP1 contains a classical bipartite NLS 1666-GKRKLITSEEERSPAKRGRKS-1686, which enables the importin-mediated nuclear transport of 53BP1. Additionally, we found that posttranslational modification within the NLS region can regulate 53BP1 nuclear import. SIGNIFICANCE: Our results indicate that integrity of the NLS is important for 53BP1 nuclear localisation. Precise mapping of the NLS will facilitate further studies on the effect of posttranslational modifications and somatic mutations on the nuclear localisation 53BP1 and DNA repair.

• Klíčová slova
• DNA damage/repair, Intracellular compartmentalisation, Post-translational modification,
• MeSH
• 53BP1 genetika   metabolismus   MeSH
• aktivní transport - buněčné jádro MeSH
• arginin chemie   genetika   metabolismus   MeSH
• buněčné jádro genetika   metabolismus   MeSH
• fosforylace MeSH
• HEK293 buňky MeSH
• jaderné lokalizační signály * MeSH
• karyoferiny genetika   metabolismus   MeSH
• lidé MeSH
• lysin chemie   genetika   metabolismus   MeSH
• nádorové buňky kultivované MeSH
• nádory kostí genetika   metabolismus   patologie   MeSH
• osteosarkom genetika   metabolismus   patologie   MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• 53BP1 MeSH
• arginin MeSH
• jaderné lokalizační signály * MeSH
• karyoferiny MeSH
• lysin MeSH
• TP53BP1 protein, human MeSH Prohlížeč

The mechanism used by mouse polyomavirus (MPyV) overcomes the crowded cytosol to reach the nucleus has not been fully elucidated. Here, we investigated the involvement of importin α/β1 mediated transport in the delivery of MPyV genomes into the nucleus. Interactions of the virus with importin β1 were studied by co-immunoprecipitation and proximity ligation assay. For infectivity and nucleus delivery assays, the virus and its capsid proteins mutated in the nuclear localization signals (NLSs) were prepared and produced. We found that at early times post infection, virions bound importin β1 in a time dependent manner with a peak of interactions at 6 h post infection. Mutation analysis revealed that only when the NLSs of both VP1 and VP2/3 were disrupted, virus did not bind efficiently to importin β1 and its infectivity remarkably decreased (by 80%). Nuclear targeting of capsid proteins was improved when VP1 and VP2 were co-expressed. VP1 and VP2 were effectively delivered into the nucleus, even when one of the NLS, either VP1 or VP2, was disrupted. Altogether, our results showed that MPyV virions can use VP1 and/or VP2/VP3 NLSs in concert or individually to bind importins to deliver their genomes into the cell nucleus.

• Klíčová slova
• capsid proteins, importin β1, mouse polyomavirus, nuclear localization signal, trafficking into the nucleus,
• MeSH
• biologický transport MeSH
• buněčné jádro MeSH
• buněčné linie MeSH
• DNA virů metabolismus   MeSH
• fluorescenční protilátková technika MeSH
• jaderné lokalizační signály genetika   MeSH
• karyoferiny metabolismus   MeSH
• mutace MeSH
• myši MeSH
• polyomavirové infekce metabolismus   virologie   MeSH
• Polyomavirus fyziologie   ultrastruktura   MeSH
• sestavení viru MeSH
• substituce aminokyselin MeSH
• vazba proteinů MeSH
• virové plášťové proteiny genetika   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• DNA virů MeSH
• jaderné lokalizační signály MeSH
• karyoferiny MeSH
• virové plášťové proteiny MeSH