scholarly journals A Beckwith–Wiedemann-Associated CDKN1C Mutation Allows the Identification of a Novel Nuclear Localization Signal in Human p57Kip2

2021 ◽  
Vol 22 (14) ◽  
pp. 7428
Author(s):  
Emanuela Stampone ◽  
Debora Bencivenga ◽  
Clementina Barone ◽  
Marilena Di Finizio ◽  
Fulvio Della Ragione ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Cellular Localization ◽  
Genetic Diseases ◽  
Mutant Form ◽  
Nuclear Entry ◽  
Gene Encoding ◽  
Inhibitory Function ◽  
C Terminus ◽  
Localization Signal

p57Kip2 protein is a member of the CIP/Kip family, mainly localized in the nucleus where it exerts its Cyclin/CDKs inhibitory function. In addition, the protein plays key roles in embryogenesis, differentiation, and carcinogenesis depending on its cellular localization and interactors. Mutations of CDKN1C, the gene encoding human p57Kip2, result in the development of different genetic diseases, including Beckwith–Wiedemann, IMAGe and Silver–Russell syndromes. We investigated a specific Beckwith–Wiedemann associated CDKN1C change (c.946 C>T) that results in the substitution of the C-terminal amino acid (arginine 316) with a tryptophan (R316W-p57Kip2). We found a clear redistribution of R316W-p57Kip2, in that while the wild-type p57Kip2 mostly occurs in the nucleus, the mutant form is also distributed in the cytoplasm. Transfection of two expression constructs encoding the p57Kip2 N- and C-terminal domain, respectively, allows the mapping of the nuclear localization signal(s) (NLSs) between residues 220–316. Moreover, by removing the basic RKRLR sequence at the protein C-terminus (from 312 to 316 residue), p57Kip2 was confined in the cytosol, implying that this sequence is absolutely required for nuclear entry. In conclusion, we identified an unreported p57Kip2 NLS and suggest that its absence or mutation might be of relevance in CDKN1C-associated human diseases determining significant changes of p57Kip2 localization/regulatory roles.

scholarly journals The C-Terminal Region of PTHrP, in Addition to the Nuclear Localization Signal, Is Essential for the Intracrine Stimulation of Proliferation in Vascular Smooth Muscle Cells

Endocrinology ◽  
2001 ◽  
Vol 142 (9) ◽  
pp. 4096-4105 ◽  
Author(s):  
F. de Miguel ◽  
N. Fiaschi-Taesch ◽  
J. C. López-Talavera ◽  
K. K. Takane ◽  
T. Massfelder ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Smooth Muscle Cells ◽  
Vascular Smooth Muscle Cells ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Muscle Cells ◽  
Nuclear Entry ◽  
C Terminus ◽  
Localization Signal

Abstract PTHrP is secreted by most cell types. In addition to a paracrine/autocrine role, PTHrP has “intracrine” actions, entering the nuclear compartment under the direction of a classic bipartite nuclear localization signal. In vascular smooth muscle cells, nuclear entry stimulates mitogenesis. In the current study, we sought to more precisely define the regions of PTHrP required for the activation of mitogenesis in vascular smooth muscle cells. PTHrP deletion mutants missing large regions [i.e. the signal peptide, N terminus (1–36), mid region (38–86), nuclear localization signal, C terminus (108–139), or combinations of the above] were expressed in A-10 vascular smooth muscle cells. The consequences on nuclear localization and proliferation were examined. Deletion of the nuclear localization signal prevented nuclear entry and slowed proliferation. Deletion of the highly conserved N terminus or mid region had no impact on nuclear localization or on proliferation. Deletion of the C terminus had no deleterious effect on nuclear localization but dramatically reduced proliferation. Thus, the nuclear localization signal is both necessary and sufficient for nuclear localization of PTHrP. In contrast, activation of proliferation in vascular smooth muscle cells requires both an intact nuclear localization signal and an intact C terminus. Whereas the nuclear localization signal is required for nuclear entry, the C terminus may serve a trans-activating function to stimulate mitogenesis once inside the nucleus of vascular smooth muscle cells.

No Enhancement of Nuclear Entry by Direct Conjugation of a Nuclear Localization Signal Peptide to Linearized DNA

2003 ◽  
Vol 14 (6) ◽  
pp. 1197-1202 ◽  
Author(s):  
Mitsuhide Tanimoto ◽  
Hiroyuki Kamiya ◽  
Noriaki Minakawa ◽  
Akira Matsuda ◽  
Hideyoshi Harashima
Keyword(s):  
Nuclear Localization ◽  
Signal Peptide ◽  
Nuclear Localization Signal ◽  
Nuclear Entry ◽  
Localization Signal

scholarly journals Dual role of the adenovirus pVI C terminus as a nuclear localization signal and activator of the viral protease

2004 ◽  
Vol 85 (11) ◽  
pp. 3367-3376 ◽  
Author(s):  
K. S. Honkavuori ◽  
B. D. Pollard ◽  
M. S. Rodriguez ◽  
R. T. Hay ◽  
G. D. Kemp
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Human Adenovirus ◽  
Dual Role ◽  
Adenovirus Infection ◽  
Heterologous Proteins ◽  
Viral Protease ◽  
C Terminus ◽  
Localization Signal

Adenain, the protease produced by adenovirus, is regulated by formation of a heterodimer with an 11 aa peptide derived from the C terminus of another adenoviral protein, pVI. Here, the role of the basic motif KRRR, which is conserved in pVI sequences from human adenovirus serotypes, was investigated. It was shown that this motif is less important than the N- or C-terminal regions in the formation of the adenain–peptide heterodimer and in the activity of the subsequent complex. This motif, however, acted as a nuclear localization signal that was capable of targeting heterologous proteins to the nucleus, resulting in a distinctive intranuclear distribution consisting of discrete foci, which is similar to that found for pVI during adenovirus infection.

scholarly journals Interaction of the Influenza A Virus Polymerase PB2 C-terminal Region with Importin α Isoforms Provides Insights into Host Adaptation and Polymerase Assembly

2011 ◽  
Vol 286 (12) ◽  
pp. 10439-10448 ◽  
Author(s):  
Stephane Boivin ◽  
Darren J. Hart
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Influenza A ◽  
Host Adaptation ◽  
New Host ◽  
Adaptive Mutations ◽  
C Terminus ◽  
Importin Α ◽  
Localization Signal ◽  
Import Receptors

In the adaptation of avian viruses to mammalian hosts, mutations in the viral polymerase, notably in the PB2 subunit, play an important role. A PB2 C-terminal domain rich in putative host adaptation residues has been shown to bind importin α nuclear import receptors. Adaptation has been proposed to involve binding of PB2 to importins of the new host. To date PB2-importin complexes have been characterized semiquantitatively with no precise measurement of binding parameters. To investigate the effects of adaptive mutations on importin interaction and selectivity, surface plasmon resonance was used to compare the binding rate constants and affinities of avian H5N1 and human H3N2 PB2 C-terminal variants with importin isoforms human α 1, 3, 5 and 7, and avian α 1. Using purified proteins eliminates host environment effects and permits measurement of intrinsic affinities and rates of complex formation and dissociation. Two effects were observed: first, adaptive mutations D701N, R702K, and S714R in the nuclear localization signal domain increased 2–4-fold the association rates with avian and human importins; second, measurement of different structural forms of the PB2 C terminus demonstrated that the upstream 627 domain reduced binding affinity, consistent with a steric clash predicted from crystal structures. From these kinetic data, structural analyses, and the data of others, a model is proposed in which an increase in charged surface residues during host adaptation increases the association rate of PB2 to cytoplasmic importins and where the C-terminal 627-nuclear localization signal domain may reorganize upon importin binding, consistent with a role in active polymerase assembly.

scholarly journals Functional Evolution of the Photolyase/Cryptochrome Protein Family: Importance of the C Terminus of Mammalian CRY1 for Circadian Core Oscillator Performance

2006 ◽  
Vol 26 (5) ◽  
pp. 1743-1753 ◽  
Author(s):  
Inês Chaves ◽  
Kazuhiro Yagita ◽  
Sander Barnhoorn ◽  
Hitoshi Okamura ◽  
Gijsbertus T. J. van der Horst ◽  
...  
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Coiled Coil ◽  
Structural Similarity ◽  
Light Signaling ◽  
Core Domain ◽  
Coiled Coil Domain ◽  
C Terminus ◽  
Localization Signal ◽  
Species Specific

ABSTRACT Cryptochromes (CRYs) are composed of a core domain with structural similarity to photolyase and a distinguishing C-terminal extension. While plant and fly CRYs act as circadian photoreceptors, using the C terminus for light signaling, mammalian CRY1 and CRY2 are integral components of the circadian oscillator. However, the function of their C terminus remains to be resolved. Here, we show that the C-terminal extension of mCRY1 harbors a nuclear localization signal and a putative coiled-coil domain that drive nuclear localization via two independent mechanisms and shift the equilibrium of shuttling mammalian CRY1 (mCRY1)/mammalian PER2 (mPER2) complexes towards the nucleus. Importantly, deletion of the complete C terminus prevents mCRY1 from repressing CLOCK/BMAL1-mediated transcription, whereas a plant photolyase gains this key clock function upon fusion to the last 100 amino acids of the mCRY1 core and its C terminus. Thus, the acquirement of different (species-specific) C termini during evolution not only functionally separated cryptochromes from photolyase but also caused diversity within the cryptochrome family.

scholarly journals Splicing Factor hSlu7 Contains a Unique Functional Domain Required to Retain the Protein within the Nucleus

2004 ◽  
Vol 15 (8) ◽  
pp. 3782-3795 ◽  
Author(s):  
Noam Shomron ◽  
Mika Reznik ◽  
Gil Ast
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Cellular Localization ◽  
Correct Selection ◽  
Functional Domain ◽  
Protein Levels ◽  
Localization Signal ◽  
Precursor Mrna ◽  
Small Nuclear Ribonucleoproteins ◽  
Selection Of

Precursor-mRNA splicing removes the introns and ligates the exons to form a mature mRNA. This process is carried out in a spliceosomal complex containing >150 proteins and five small nuclear ribonucleoproteins. Splicing protein hSlu7 is required for correct selection of the 3′ splice site. Here, we identify by bioinformatics and mutational analyses three functional domains of the hSlu7 protein that have distinct roles in its subcellular localization: a nuclear localization signal, a zinc-knuckle motif, and a lysine-rich region. The zinc-knuckle motif is embedded within the nuclear localization signal in a unique functional structure that is not required for hSlu7's entrance into the nucleus but rather to maintain hSlu7 inside it, preventing its shuttle back to the cytoplasm via the chromosomal region maintenance 1 pathway. Thus, the zinc-knuckle motif of hSlu7 determines the cellular localization of the protein through a nucleocytoplasmic-sensitive shuttling balance. Altogether, this indicates that zinc-dependent nucleocytoplasmic shuttling might be the possible molecular basis by which hSlu7 protein levels are regulated within the nucleus.

scholarly journals The ORF012 Gene of Marek's Disease Virus Type 1 Produces a Spliced Transcript and Encodes a Novel Nuclear Phosphoprotein Essential for Virus Growth

2014 ◽  
Vol 89 (2) ◽  
pp. 1348-1363 ◽  
Author(s):  
Timo Schippers ◽  
Keith Jarosinski ◽  
Nikolaus Osterrieder
Keyword(s):  
Disease Virus ◽  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Marek's Disease Virus ◽  
Marek's Disease ◽  
Marek’S Disease Virus ◽  
Marek’S Disease ◽  
Virus Growth ◽  
C Terminus ◽  
Localization Signal

ABSTRACTMarek's disease virus (MDV), an alphaherpesvirus, is the causative agent of a lethal disease in chickens characterized by generalized nerve inflammation and rapid lymphoma development. The extensive colinearity of the MDV genome with those of related herpesviruses has eased functional characterization of many MDV genes. However, MDV carries a number of unique open reading frames (ORFs) that have not yet been investigated regarding their coding potentials and the functions of their products. Among these unique ORFs are two putative ORFs, ORF011 and ORF012, which are found at the extreme left end of the MDV unique long region. Using reverse transcriptase PCR, we showed that ORF011 and ORF012 are not individual genes but form a single gene through mRNA splicing of a small intron, resulting in the novel ORF012. We generated an ORF012-null virus using an infectious clone of MDV strain RB-1B. The deletion virus had a marked growth defectin vitroand could not be passaged in cultured cells, suggesting an essential role for the ORF012 product in virus replication. Further studies revealed that protein 012 (p012) localized to the nucleus in transfected and infected cells, and we identified by site-directed mutagenesis and green fluorescent protein (GFP) reporter fusion assays a nuclear localization signal (NLS) that was mapped to a 23-amino-acid sequence at the protein's C terminus. Nuclear export was blocked using leptomycin B, suggesting a potential role for p012 as a nuclear/cytoplasmic shuttling protein. Finally, p012 is phosphorylated at multiple residues, a modification that could possibly regulate its subcellular distribution.IMPORTANCEMarek's disease virus (MDV) causes a devastating oncogenic disease in chickens with high morbidity and mortality. The costs for disease prevention reach several billion dollars annually. The functional investigation of MDV genes is necessary to understand its complex replication cycle, which eventually could help us to interfere with MDV and herpesviral pathogenesis. We have identified a previously unidentified phosphoprotein encoded by MDV ORF012. We were able to show experimentally that predicted splicing of the gene based on bioinformatics data does indeed occur during replication. The newly identified p012 is essential for MDV replication and localizes to the nucleus due to the presence of a transferable nuclear localization signal at its C terminus. Our results also imply that p012 could constitute a nucleocytoplasmic shuttle protein, a feature that could prove interesting and important.

scholarly journals Duck Plague Virus pUL48 Protein Activates the Immediate-Early Gene to Initiate the Transcription of the Virus Gene

2021 ◽  
Vol 12 ◽  
Author(s):  
Tong Zhou ◽  
Dengjian Fan ◽  
Mingshu Wang ◽  
Anchun Cheng ◽  
Ying Wu ◽  
...  
Keyword(s):  
Amino Acids ◽  
Nuclear Localization ◽  
Transcriptional Activation ◽  
Nuclear Localization Signal ◽  
Activation Function ◽  
Immediate Early ◽  
Luciferase Reporter ◽  
Nuclear Entry ◽  
Duck Plague Virus ◽  
Localization Signal

Duck plague caused by the duck plague virus (DPV) is an infectious disease that seriously harms the waterfowl breeding industry. The VP16 protein of α herpesvirus can bind to specific cis-acting elements upstream of the promoter of the immediate-early (IE, α) gene to promote the transcription of the IE gene, so it is also called the trans-inducer of IE gene (α-TIF). However, no studies on DPV α-TIF have been reported. This study investigated the DPV pUL48, a homolog of HSV-1 VP16, transcriptional activation region, target sequence, and viral protein affecting its transcriptional activation using a dual-luciferase reporter gene detection system, and pUL48 was identified as the α-TIF of DPV. (1) The regulation of pUL48 on DPV different gene promoters showed that pUL48 could activate all the promoters of IE genes (ICP4, ICP22, and ICP27) but not the promoters of early and late genes. (2) The activity of pUL48 to ICP4 and ICP22 promoters with different upstream lengths showed that pUL48 activated ICP4 and ICP22 promoters by acting on TAATGA (T) TAT element upstream of ICP4 promoter and TAATTATAT element upstream of ICP22 promoter, respectively. (3) Transcriptional activation of IE gene by truncated proteins of different lengths at the N-terminal of pUL48 was detected. The results showed that the transcriptional activation domain of pUL48 was amino acids 1–60 at the N-terminal, and amino acids 1–20 was its core region. In addition, it was found that pUL14, pUL46, and pUL47 significantly promoted the transcriptional activation of pUL48. The effects of loss of pUL47 and its nuclear localization signal on the nuclear entry and transcriptional activation function of pUL48 were further examined. The results showed that pUL47 could promote the nuclear entry of pUL48 through its nuclear localization signal at positions 40–50 and 768–777 amino acids, thus, enhancing the transcriptional activation function of pUL48 and synergistic promotion of viral gene transcription.

scholarly journals Invading the Yeast Nucleus: a Nuclear Localization Signal at the C Terminus of Ty1 Integrase Is Required for Transposition In Vivo

1998 ◽  
Vol 18 (2) ◽  
pp. 1115-1124 ◽  
Author(s):  
Margaret A. Kenna ◽  
Carrie Baker Brachmann ◽  
Scott E. Devine ◽  
Jef D. Boeke
Keyword(s):  
Nuclear Localization ◽  
Nuclear Localization Signal ◽  
Reverse Transcriptase Activity ◽  
Deletion Mutants ◽  
Amino Acid Residues ◽  
Wild Type ◽  
C Terminus ◽  
Localization Signal

ABSTRACT Retrotransposon Ty1 faces a formidable cell barrier during transposition—the yeast nuclear membrane which remains intact throughout the cell cycle. We investigated the mechanism by which transposition intermediates are transported from the cytoplasm (the presumed site of Ty1 DNA synthesis) to the nucleus, where they are integrated into the genome. Ty1 integrase has a nuclear localization signal (NLS) at its C terminus. Both full-length integrase and a C-terminal fragment localize to the nucleus. C-terminal deletion mutants in Ty1 integrase were used to map the putative NLS to the last 74 amino acid residues of integrase. Mutations in basic segments within this region decreased retrotransposition at least 50-fold in vivo. Furthermore, these mutant integrase proteins failed to localize to the nucleus. Production of virus-like particles, reverse transcriptase activity, and complete in vitro Ty1 integration resembled wild-type levels, consistent with failure of the mutant integrases to enter the nucleus.

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