One of the remarkable features of eukaryotes is the nucleus, delimited by the nuclear envelope (NE), a complex structure and home to the nuclear lamina and nuclear pore complex (NPC). For decades, these structures were believed to be mainly architectural elements and, in the case of the NPC, simply facilitating nucleocytoplasmic trafficking. More recently, the critical roles of the lamina, NPC and other NE constituents in genome organisation, maintaining chromosomal domains and regulating gene expression have been recognised. Importantly, mutations in genes encoding lamina and NPC components lead to pathogenesis in humans, while pathogenic protozoa disrupt the progression of normal development and expression of pathogenesis-related genes. Here, we review features of the lamina and NPC across eukaryotes and discuss how these elements are structured in trypanosomes, protozoa of high medical and veterinary importance, highlighting lineage-specific and conserved aspects of nuclear organisation.
- Klíčová slova
- evolutionary diversity, nuclear lamina, nuclear pore complex, nucleus, trypanosoma,
- MeSH
- aktivní transport - buněčné jádro fyziologie MeSH
- jaderný obal MeSH
- jaderný pór genetika metabolismus MeSH
- komplex proteinů jaderného póru * metabolismus MeSH
- lidé MeSH
- Trypanosoma * genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Názvy látek
- komplex proteinů jaderného póru * MeSH
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
The nuclear pore complex (NPC) facilitates the trafficking of proteins and RNA between the nucleus and cytoplasm. The role of nucleoporins (Nups) in transport in the context of the NPC is well established, yet their function in tRNA export has not been fully explored. We selected several nucleoporins from different parts of the NPC to investigate their potential role in tRNA trafficking in Trypanosoma brucei. We show that while all of the nucleoporins studied are essential for cell viability, only TbNup62 and TbNup53a function in tRNA export. In contrast to homologs in yeast TbNup144 and TbNup158, which are part of the inner and outer ring of the NPC, have no role in nuclear tRNA trafficking. Instead, TbNup144 plays a critical role in nuclear division, highlighting the role of nucleoporins beyond nucleocytoplasmic transport. These results suggest that the location of nucleoporins within the NPC is crucial to maintaining various cellular processes.
- Klíčová slova
- FG-Nups, NPC, Trypanosoma brucei, nuclear division, nucleoporins, tRNA trafficking,
- MeSH
- aktivní transport - buněčné jádro MeSH
- buněčné jádro metabolismus MeSH
- jaderný pór * genetika metabolismus MeSH
- komplex proteinů jaderného póru * genetika MeSH
- Saccharomyces cerevisiae genetika metabolismus MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- komplex proteinů jaderného póru * MeSH
Export of RNA from the nucleus is essential for all eukaryotic cells and has emerged as a major step in the control of gene expression. mRNA molecules are required to complete a complex series of processing events and pass a quality control system to protect the cytoplasm from the translation of aberrant proteins. Many of these events are highly conserved across eukaryotes, reflecting their ancient origin, but significant deviation from a canonical pathway as described from animals and fungi has emerged in the trypanosomatids. With significant implications for the mechanisms that control gene expression and hence differentiation, responses to altered environments and fitness as a parasite, these deviations may also reveal additional, previously unsuspected, mRNA export pathways.
- Klíčová slova
- eukaryogenesis, mRNA export, nuclear pore complex, polycistronic transcription, trans-splicing, trypanosomes,
- MeSH
- aktivní transport - buněčné jádro genetika MeSH
- buněčné jádro genetika metabolismus MeSH
- messenger RNA genetika MeSH
- RNA * genetika metabolismus MeSH
- Trypanosoma * genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- přehledy MeSH
- Research Support, N.I.H., Extramural MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Názvy látek
- messenger RNA MeSH
- RNA * MeSH
In trypanosomatids, transcription is polycistronic and all mRNAs are processed by trans-splicing, with export mediated by noncanonical mechanisms. Although mRNA export is central to gene regulation and expression, few orthologs of proteins involved in mRNA export in higher eukaryotes are detectable in trypanosome genomes, necessitating direct identification of protein components. We previously described conserved mRNA export pathway components in Trypanosoma cruzi, including orthologs of Sub2, a component of the TREX complex, and eIF4AIII (previously Hel45), a core component of the exon junction complex (EJC). Here, we searched for protein interactors of both proteins using cryomilling and mass spectrometry. Significant overlap between TcSub2 and TceIF4AIII-interacting protein cohorts suggests that both proteins associate with similar machinery. We identified several interactions with conserved core components of the EJC and multiple additional complexes, together with proteins specific to trypanosomatids. Additional immunoisolations of kinetoplastid-specific proteins both validated and extended the superinteractome, which is capable of supporting RNA processing from splicing through to nuclear export and cytoplasmic events. We also suggest that only proteomics is powerful enough to uncover the high connectivity between multiple aspects of mRNA metabolism and to uncover kinetoplastid-specific components that create a unique amalgam to support trypanosome mRNA maturation.
- Klíčová slova
- evolution, gene expression, mRNA export, proteomics, trypanosomes,
- MeSH
- aktivní transport - buněčné jádro MeSH
- proteomika * MeSH
- RNA MeSH
- sestřih RNA MeSH
- transport RNA MeSH
- Trypanosoma cruzi * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- RNA MeSH
Kinetoplastids, including Trypanosoma brucei, control gene expression primarily at the posttranscriptional level. Nuclear mRNA export is an important, but understudied, step in this process. The general heterodimeric export factors, Mex67/Mtr2, function in the export of mRNAs and tRNAs in T. brucei, but RNA binding proteins (RBPs) that regulate export processes by controlling the dynamics of Mex67/Mtr2 ribonucleoprotein formation or transport have not been identified. Here, we report that DRBD18, an essential and abundant T. brucei RBP, associates with Mex67/Mtr2 in vivo, likely through its direct interaction with Mtr2. DRBD18 downregulation results in partial accumulation of poly(A)+ mRNA in the nucleus, but has no effect on the localization of intron-containing or mature tRNAs. Comprehensive analysis of transcriptomes from whole-cell and cytosol in DRBD18 knockdown parasites demonstrates that depletion of DRBD18 leads to impairment of nuclear export of a subset of mRNAs. CLIP experiments reveal the association of DRBD18 with several of these mRNAs. Moreover, DRBD18 knockdown leads to a partial accumulation of the Mex67/Mtr2 export receptors in the nucleus. Taken together, the current study supports a model in which DRBD18 regulates the selective nuclear export of mRNAs by promoting the mobilization of export competent mRNPs to the cytosol through the nuclear pore complex.
- Klíčová slova
- FISH, RNA binding protein, RNAseq, mRNA export, nucleoporin, trypanosome,
- MeSH
- aktivní transport - buněčné jádro MeSH
- genový knockdown metody MeSH
- membránové transportní proteiny metabolismus MeSH
- messenger RNA metabolismus MeSH
- nukleocytoplazmatické transportní proteiny metabolismus MeSH
- proteiny vázající RNA genetika metabolismus MeSH
- protozoální proteiny genetika metabolismus MeSH
- regulace genové exprese MeSH
- RNA transferová metabolismus MeSH
- transkriptom MeSH
- transport RNA 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
- membránové transportní proteiny MeSH
- messenger RNA MeSH
- nukleocytoplazmatické transportní proteiny MeSH
- proteiny vázající RNA MeSH
- protozoální proteiny MeSH
- RNA transferová MeSH
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
- antitumorózní látky farmakologie terapeutické užití 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
- 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
- antitumorózní látky MeSH
- hydraziny MeSH
- karyoferiny MeSH
- receptory cytoplazmatické a nukleární MeSH
- selinexor MeSH Prohlížeč
- triazoly MeSH
Shuttling proteins are molecules that can facilitate transport through the nuclear envelope. A very large number of proteins are involved in this process that includes nuclear pore buildup, signal, receptor and enzyme proteins. There are many examples of proteins whose biological activity depends on nucleocytoplasmic transport. Very often they are largely responsible for the proper occurrence of cell division, maturation, development and differentiation. Thanks to the well mastered methods of in vitro cell culture, it is possible to trace the levels of protein expression and their distribution in cells. Advanced molecular techniques allow for precise determination of their displacement in time. Several studies are still being carried out, using primary cultures, to identify the factors that determine the maturation, development and differentiation of cells. In understanding of the detailed mechanisms controlling cell life, the key is not the level of expression of a specific protein, but its distribution in individual cellular compartments.
- Klíčová slova
- in vitro growth and development, nuclear-cytoplasmic shuttling, primary cell model,
- MeSH
- aktivní transport - buněčné jádro * MeSH
- buněčné jádro metabolismus MeSH
- cytoplazma metabolismus MeSH
- lidé MeSH
- primární buněčná kultura * MeSH
- proteiny metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- dopisy MeSH
- Názvy látek
- proteiny MeSH
Nicotinamide phosphoribosyltransferase (NAMPT) is located in both the nucleus and cytoplasm and has multiple biological functions including catalyzing the rate-limiting step in NAD synthesis. Moreover, up-regulated NAMPT expression has been observed in many cancers. However, the determinants and regulation of NAMPT's nuclear transport are not known. Here, we constructed a GFP-NAMPT fusion protein to study NAMPT's subcellular trafficking. We observed that in unsynchronized 3T3-L1 preadipocytes, 25% of cells had higher GFP-NAMPT fluorescence in the cytoplasm, and 62% had higher GFP-NAMPT fluorescence in the nucleus. In HepG2 hepatocytes, 6% of cells had higher GFP-NAMPT fluorescence in the cytoplasm, and 84% had higher GFP-NAMPT fluorescence in the nucleus. In both 3T3-L1 and HepG2 cells, GFP-NAMPT was excluded from the nucleus immediately after mitosis and migrated back into it as the cell cycle progressed. In HepG2 cells, endogenous, untagged NAMPT displayed similar changes with the cell cycle, and in nonmitotic cells, GFP-NAMPT accumulated in the nucleus. Similarly, genotoxic, oxidative, or dicarbonyl stress also caused nuclear NAMPT localization. These interventions also increased poly(ADP-ribosyl) polymerase and sirtuin activity, suggesting an increased cellular demand for NAD. We identified a nuclear localization signal in NAMPT and amino acid substitution in this sequence (424RSKK to ASGA), which did not affect its enzymatic activity, blocked nuclear NAMPT transport, slowed cell growth, and increased histone H3 acetylation. These results suggest that NAMPT is transported into the nucleus where it presumably increases NAD synthesis required for cell proliferation. We conclude that specific inhibition of NAMPT transport into the nucleus might be a potential avenue for managing cancer.
- Klíčová slova
- GFP fusion, NAMPT, cancer, epigenetics, nicotinamide adenine dinucleotide (NAD), nuclear localization, pre–B cell colony enhancing factor (PBEF), sirtuin, visfatin,
- MeSH
- akrylamidy farmakologie MeSH
- aktivní transport - buněčné jádro MeSH
- buněčné jádro metabolismus MeSH
- buňky 3T3-L1 MeSH
- buňky Hep G2 MeSH
- cytoplazma metabolismus MeSH
- histony metabolismus MeSH
- kontrolní body buněčného cyklu MeSH
- lidé MeSH
- mutageneze cílená MeSH
- myši MeSH
- NAD metabolismus MeSH
- nikotinamidfosforibosyltransferasa chemie genetika metabolismus MeSH
- oxidační stres MeSH
- piperidiny farmakologie MeSH
- poly(ADP-ribosa)-polymerasy metabolismus MeSH
- proliferace buněk MeSH
- rekombinantní fúzní proteiny chemie genetika metabolismus MeSH
- sirtuiny metabolismus MeSH
- viabilita buněk účinky léků MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- akrylamidy MeSH
- histony MeSH
- N-(4-(1-benzoylpiperidin-4-yl)butyl)-3-(pyridin-3-yl)acrylamide MeSH Prohlížeč
- NAD MeSH
- nikotinamidfosforibosyltransferasa MeSH
- piperidiny MeSH
- poly(ADP-ribosa)-polymerasy MeSH
- rekombinantní fúzní proteiny MeSH
- sirtuiny MeSH
