The RNA content is crucial for the formation of nuclear compartments, such as nuclear speckles and nucleoli. Phosphatidylinositol 4,5-bisphosphate (PIP2) is found in nuclear speckles, nucleoli, and nuclear lipid islets and is involved in RNA polymerase I/II transcription. Intriguingly, the nuclear localization of PIP2 was also shown to be RNA-dependent. We therefore investigated whether PIP2 and RNA cooperate in the establishment of nuclear architecture. In this study, we unveiled the RNA-dependent PIP2-associated (RDPA) nuclear proteome in human cells by mass spectrometry. We found that intrinsically disordered regions (IDRs) with polybasic PIP2-binding K/R motifs are prevalent features of RDPA proteins. Moreover, these IDRs of RDPA proteins exhibit enrichment for phosphorylation, acetylation, and ubiquitination sites. Our results show for the first time that the RDPA protein Bromodomain-containing protein 4 (BRD4) associates with PIP2 in the RNA-dependent manner via electrostatic interactions, and that altered PIP2 levels affect the number of nuclear foci of BRD4 protein. Thus, we propose that PIP2 spatiotemporally orchestrates nuclear processes through association with RNA and RDPA proteins and affects their ability to form foci presumably via phase separation. This suggests the pivotal role of PIP2 in the establishment of a functional nuclear architecture competent for gene expression.
- MeSH
- buněčné jádro * metabolismus genetika MeSH
- fosfatidylinositol-4,5-difosfát * metabolismus MeSH
- fosforylace MeSH
- jaderné proteiny * metabolismus genetika MeSH
- lidé MeSH
- proteiny buněčného cyklu metabolismus genetika MeSH
- proteiny obsahující bromodoménu MeSH
- RNA metabolismus genetika MeSH
- transkripční faktory * metabolismus genetika MeSH
- vazba proteinů MeSH
- vnitřně neuspořádané proteiny * metabolismus genetika chemie MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
[Figure: see text].
- MeSH
- adaptorové proteiny signální transdukční chemie metabolismus MeSH
- DNA vazebné proteiny chemie metabolismus MeSH
- elongace genetické transkripce * MeSH
- exprese genu MeSH
- interakční proteinové domény a motivy genetika MeSH
- lidé MeSH
- mapy interakcí proteinů MeSH
- molekulární modely MeSH
- mutace MeSH
- nádorové buněčné linie MeSH
- proteinové domény MeSH
- proteiny vázající RNA chemie genetika metabolismus MeSH
- RNA-polymerasa II chemie metabolismus MeSH
- transkripční elongační faktory chemie metabolismus MeSH
- transkripční faktory chemie genetika metabolismus MeSH
- vazba proteinů MeSH
- vnitřně neuspořádané proteiny chemie metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Ameloblastin (Ambn) as an intrinsically disordered protein (IDP) stands for an important role in the formation of enamel-the hardest biomineralized tissue commonly formed in vertebrates. The human ameloblastin (AMBN) is expressed in two isoforms: full-length isoform I (AMBN ISO I) and isoform II (AMBN ISO II), which is about 15 amino acid residues shorter than AMBN ISO I. The significant feature of AMBN-its oligomerization ability-is enabled due to a specific sequence encoded by exon 5 present at the N-terminal part in both known isoforms. In this study, we characterized AMBN ISO I and AMBN ISO II by biochemical and biophysical methods to determine their common features and differences. We confirmed that both AMBN ISO I and AMBN ISO II form oligomers in in vitro conditions. Due to an important role of AMBN in biomineralization, we further addressed the calcium (Ca2+)-binding properties of AMBN ISO I and ISO II. The binding properties of AMBN to Ca2+ may explain the role of AMBN in biomineralization and more generally in Ca2+ homeostasis processes.
- MeSH
- biologické modely MeSH
- hydrodynamika MeSH
- lidé MeSH
- multimerizace proteinu MeSH
- protein - isoformy MeSH
- proteiny vázající vápník chemie metabolismus MeSH
- proteiny zubní skloviny chemie metabolismus MeSH
- spektrální analýza MeSH
- teplota MeSH
- vápník metabolismus MeSH
- vazba proteinů MeSH
- vnitřně neuspořádané proteiny metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
In addition to their force-generating motor domains, kinesin motor proteins feature various accessory domains enabling them to fulfill a variety of functions in the cell. Human kinesin-3, Kif14, localizes to the midbody of the mitotic spindle and is involved in the progression of cytokinesis. The specific motor properties enabling Kif14's cellular functions, however, remain unknown. Here, we show in vitro that the intrinsically disordered N-terminal domain of Kif14 enables unique functional diversity of the kinesin. Using single molecule TIRF microscopy, we found that Kif14 exists either as a diffusible monomer or as processive dimer and that the disordered domain (1) enables diffusibility of the monomeric Kif14, (2) renders the dimeric Kif14 super-processive and enables the kinesin to pass through highly crowded areas, (3) enables robust, autonomous Kif14 tracking of growing microtubule tips, independent of microtubule end-binding (EB) proteins, and (4) is sufficient to enable crosslinking of parallel microtubules and necessary to enable Kif14-driven sliding of antiparallel ones. We explain these features of Kif14 by the observed diffusible interaction of the disordered domain with the microtubule lattice and the observed increased affinity of the disordered domain for GTP-bound tubulin. We suggest that the disordered domain tethers the motor domain to the microtubule providing a diffusible foothold and a regulatory hub, tuning the kinesin's interaction with microtubules. Our findings thus exemplify pliable protein tethering as a fundamental mechanism of molecular motor regulation.
- MeSH
- aparát dělícího vřeténka fyziologie MeSH
- cytokineze * MeSH
- kineziny chemie genetika metabolismus MeSH
- lidé MeSH
- mikrotubuly metabolismus MeSH
- onkogenní proteiny chemie genetika metabolismus MeSH
- vazba proteinů MeSH
- vnitřně neuspořádané proteiny chemie genetika metabolismus MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Intracellular trafficking of organelles, driven by kinesin-1 stepping along microtubules, underpins essential cellular processes. In absence of other proteins on the microtubule surface, kinesin-1 performs micron-long runs. Under crowding conditions, however, kinesin-1 motility is drastically impeded. It is thus unclear how kinesin-1 acts as an efficient transporter in intracellular environments. Here, we demonstrate that TRAK1 (Milton), an adaptor protein essential for mitochondrial trafficking, activates kinesin-1 and increases robustness of kinesin-1 stepping on crowded microtubule surfaces. Interaction with TRAK1 i) facilitates kinesin-1 navigation around obstacles, ii) increases the probability of kinesin-1 passing through cohesive islands of tau and iii) increases the run length of kinesin-1 in cell lysate. We explain the enhanced motility by the observed direct interaction of TRAK1 with microtubules, providing an additional anchor for the kinesin-1-TRAK1 complex. Furthermore, TRAK1 enables mitochondrial transport in vitro. We propose adaptor-mediated tethering as a mechanism regulating kinesin-1 motility in various cellular environments.
- MeSH
- adaptorové proteiny vezikulární transportní genetika izolace a purifikace metabolismus MeSH
- fluorescenční mikroskopie MeSH
- kineziny genetika izolace a purifikace metabolismus MeSH
- luminescentní proteiny genetika metabolismus MeSH
- mikrotubuly metabolismus MeSH
- mitochondrie metabolismus MeSH
- myši MeSH
- nádorové buněčné linie MeSH
- proteiny tau genetika metabolismus MeSH
- rekombinantní proteiny genetika metabolismus MeSH
- vnitřně neuspořádané proteiny genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs) are now recognised as major determinants in cellular regulation. This white paper presents a roadmap for future e-infrastructure developments in the field of IDP research within the ELIXIR framework. The goal of these developments is to drive the creation of high-quality tools and resources to support the identification, analysis and functional characterisation of IDPs. The roadmap is the result of a workshop titled "An intrinsically disordered protein user community proposal for ELIXIR" held at the University of Padua. The workshop, and further consultation with the members of the wider IDP community, identified the key priority areas for the roadmap including the development of standards for data annotation, storage and dissemination; integration of IDP data into the ELIXIR Core Data Resources; and the creation of benchmarking criteria for IDP-related software. Here, we discuss these areas of priority, how they can be implemented in cooperation with the ELIXIR platforms, and their connections to existing ELIXIR Communities and international consortia. The article provides a preliminary blueprint for an IDP Community in ELIXIR and is an appeal to identify and involve new stakeholders.
p53 is an intrinsically disordered protein with a large number of post-translational modifications and interacting partners. The hierarchical order and subcellular location of these events are still poorly understood. The activation of p53 during the DNA damage response (DDR) requires a switch in the activity of the E3 ubiquitin ligase MDM2 from a negative to a positive regulator of p53. This is mediated by the ATM kinase that regulates the binding of MDM2 to the p53 mRNA facilitating an increase in p53 synthesis. Here we show that the binding of MDM2 to the p53 mRNA brings ATM to the p53 polysome where it phosphorylates the nascent p53 at serine 15 and prevents MDM2-mediated degradation of p53. A single synonymous mutation in p53 codon 22 (L22L) prevents the phosphorylation of the nascent p53 protein and the stabilization of p53 following genotoxic stress. The ATM trafficking from the nucleus to the p53 polysome is mediated by MDM2, which requires its interaction with the ribosomal proteins RPL5 and RPL11. These results show how the ATM kinase phosphorylates the p53 protein while it is being synthesized and offer a novel mechanism whereby a single synonymous mutation controls the stability and activity of the encoded protein.
- MeSH
- ATM protein genetika metabolismus MeSH
- buňky A549 MeSH
- ELISA MeSH
- fosforylace genetika fyziologie MeSH
- lidé MeSH
- malá interferující RNA metabolismus MeSH
- messenger RNA metabolismus MeSH
- mutace genetika MeSH
- nádorové buněčné linie MeSH
- nádorový supresorový protein p53 genetika metabolismus MeSH
- polyribozomy metabolismus MeSH
- protoonkogenní proteiny c-mdm2 genetika metabolismus MeSH
- stabilita proteinů MeSH
- vnitřně neuspořádané proteiny genetika metabolismus MeSH
- western blotting MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
The transcription factor ASCIZ (ATMIN, ZNF822) has an unusually high number of recognition motifs for the product of its main target gene, the hub protein LC8 (DYNLL1). Using a combination of biophysical methods, structural analysis by NMR and electron microscopy, and cellular transcription assays, we developed a model that proposes a concerted role of intrinsic disorder and multiple LC8 binding events in regulating LC8 transcription. We demonstrate that the long intrinsically disordered C-terminal domain of ASCIZ binds LC8 to form a dynamic ensemble of complexes with a gradient of transcriptional activity that is inversely proportional to LC8 occupancy. The preference for low occupancy complexes at saturating LC8 concentrations with both human and Drosophila ASCIZ indicates that negative cooperativity is an important feature of ASCIZ-LC8 interactions. The prevalence of intrinsic disorder and multivalency among transcription factors suggests that formation of heterogeneous, dynamic complexes is a widespread mechanism for tuning transcriptional regulation.
- MeSH
- cytoplazmatické dyneiny chemie genetika metabolismus MeSH
- Drosophila melanogaster růst a vývoj metabolismus fyziologie MeSH
- dyneiny chemie genetika metabolismus MeSH
- lidé MeSH
- proteiny Drosophily chemie genetika metabolismus MeSH
- regulace genové exprese * MeSH
- transkripční faktory chemie genetika metabolismus MeSH
- vnitřně neuspořádané proteiny genetika metabolismus MeSH
- zvířata MeSH
- Check Tag
- lidé MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
The formation of mineralized tissues is governed by extracellular matrix proteins that assemble into a 3D organic matrix directing the deposition of hydroxyapatite. Although the formation of bones and dentin depends on the self-assembly of type I collagen via the Gly-X-Y motif, the molecular mechanism by which enamel matrix proteins (EMPs) assemble into the organic matrix remains poorly understood. Here we identified a Y/F-x-x-Y/L/F-x-Y/F motif, evolutionarily conserved from the first tetrapods to man, that is crucial for higher order structure self-assembly of the key intrinsically disordered EMPs, ameloblastin and amelogenin. Using targeted mutations in mice and high-resolution imaging, we show that impairment of ameloblastin self-assembly causes disorganization of the enamel organic matrix and yields enamel with disordered hydroxyapatite crystallites. These findings define a paradigm for the molecular mechanism by which the EMPs self-assemble into supramolecular structures and demonstrate that this process is crucial for organization of the organic matrix and formation of properly structured enamel.
- MeSH
- amelogenin metabolismus MeSH
- aminokyselinové motivy fyziologie MeSH
- biologická evoluce MeSH
- extracelulární matrix - proteiny metabolismus MeSH
- hydroxyapatit metabolismus MeSH
- myši MeSH
- proteiny zubní skloviny metabolismus MeSH
- sekvence aminokyselin MeSH
- vazba proteinů fyziologie MeSH
- vnitřně neuspořádané proteiny metabolismus MeSH
- zubní sklovina metabolismus MeSH
- zvířata MeSH
- Check Tag
- mužské pohlaví MeSH
- myši MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Research Support, N.I.H., Extramural MeSH
Microtubule-associated proteins (MAPs) are abundantly present in axons and dendrites, and have been shown to play crucial role during the neuronal morphogenesis. The period of main dendritic outgrowth and synaptogenesis coincides with high expression levels of one of MAPs, the MAP2c, in rats. The MAP2c is a 49.2 kDa intrinsically disordered protein. To achieve an atomic resolution characterization of such a large protein, we have developed a protocol based on the acquisition of two five-dimensional (13)C-directly detected NMR experiments. Our previously published 5D CACONCACO experiment (Nováček et al. in J Biomol NMR 50(1):1-11, 2011) provides the sequential assignment of the backbone resonances, which is not interrupted by the presence of the proline residues in the amino acid sequence. A novel 5D HC(CC-TOCSY)CACON experiment facilitates the assignment of the aliphatic side chain resonances. To streamline the data analysis, we have developed a semi-automated procedure for signal assignments. The obtained data provides the first atomic resolution insight into the conformational state of MAP2c and constitutes a model for further functional studies of MAPs.
- MeSH
- algoritmy MeSH
- glycin MeSH
- krysa rodu rattus MeSH
- molekulární sekvence - údaje MeSH
- molekulová hmotnost MeSH
- nukleární magnetická rezonance biomolekulární MeSH
- proteiny asociované s mikrotubuly chemie metabolismus MeSH
- sekundární struktura proteinů MeSH
- sekvence aminokyselin MeSH
- vnitřně neuspořádané proteiny chemie metabolismus MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
