NSP1: A yeast nuclear envelope protein localized at the nuclear pores exerts its essential function by its carboxy-terminal domain

Cell ◽  
1990 ◽  
Vol 61 (6) ◽  
pp. 979-989 ◽  
Author(s):  
Ulf Nehrbass ◽  
Hildegard Kern ◽  
Ann Mutvei ◽  
Heinz Horstmann ◽  
Brigitte Marshallsay ◽  
...  
2001 ◽  
Vol 21 (23) ◽  
pp. 7944-7955 ◽  
Author(s):  
Susanne M. Bailer ◽  
Carolin Balduf ◽  
Ed Hurt

ABSTRACT Nucleoporin Nsp1p, which has four predicted coiled-coil regions (coils 1 to 4) in the essential carboxy-terminal domain, is unique in that it is part of two distinct nuclear pore complex (NPC) subcomplexes, Nsp1p-Nup57p-Nup49p-Nic96p and Nsp1p-Nup82p-Nup159p. As shown by in vitro reconstitution, coiled-coil region 2 (residues 673 to 738) is sufficient to form heterotrimeric core complexes and can bind either Nup57p or Nup82p. Accordingly, interaction of Nup82p with Nsp1p coil 2 is competed by excess Nup57p. Strikingly, coil 3 and 4 mutants are still assembled into the core Nsp1p-Nup57p-Nup49p complex but no longer associate with Nic96p. Consistently, the Nsp1p-Nup57p-Nup49p core complex dissociates from the nuclear pores in nsp1coil 3 and 4 mutant cells, and as a consequence, defects in nuclear protein import are observed. Finally, the nsp1-L640Stemperature-sensitive mutation, which maps in coil 1, leads to a strong nuclear mRNA export defect. Thus, distinct coiled-coil regions within Nsp1p-C have separate functions that are related to the assembly of different NPC subcomplexes, nucleocytoplasmic transport, and incorporation into the nuclear pores.


1990 ◽  
Vol 111 (6) ◽  
pp. 2829-2837 ◽  
Author(s):  
E C Hurt

The yeast nuclear envelope protein NSP1 is located at the nuclear pores and mediates its essential function via the carboxy-terminal domain. The passenger protein, cytosolic dihydrofolate reductase from mouse, was fused to the 220 residue long NSP1 carboxy-terminal domain. When expressed in yeast, this chimeric protein was tightly associated with nuclear structures and was localized at the nuclear periphery very similar to authentic NSP1. Furthermore, the DHFR-C-NSP1 fusion protein was able to complement a yeast mutant lacking a functional NSP1 gene showing that DHFR-C-NSP1 fulfils the same basic function as compared to the endogenous NSP1 protein. These data also show that the NSP1 protein is composed of separate functional moieties: a carboxy-terminal domain that is sufficient to mediate the association with the nuclear periphery and an amino-terminal and middle repetitive domain with an as yet unknown function. It is suggested that heptad repeats found in the NSP1 carboxy-terminal domain, which are similar to those found in intermediate filament proteins, are crucial for mediating the association with the nuclear pores.


Life ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 674
Author(s):  
Francesco Capriglia ◽  
Francesca Rizzo ◽  
Giuseppe Petrosillo ◽  
Veronica Morea ◽  
Giulia d’Amati ◽  
...  

The m.3243A>G mutation within the mitochondrial mt-tRNALeu(UUR) gene is the most prevalent variant linked to mitochondrial encephalopathy with lactic acidosis and stroke-like episodes (MELAS) syndrome. This pathogenic mutation causes severe impairment of mitochondrial protein synthesis due to alterations of the mutated tRNA, such as reduced aminoacylation and a lack of post-transcriptional modification. In transmitochondrial cybrids, overexpression of human mitochondrial leucyl-tRNA synthetase (LARS2) has proven effective in rescuing the phenotype associated with m.3243A>G substitution. The rescuing activity resides in the carboxy-terminal domain (Cterm) of the enzyme; however, the precise molecular mechanisms underlying this process have not been fully elucidated. To deepen our knowledge on the rescuing mechanisms, we demonstrated the interactions of the Cterm with mutated mt-tRNALeu(UUR) and its precursor in MELAS cybrids. Further, the effect of Cterm expression on mitochondrial functions was evaluated. We found that Cterm ameliorates de novo mitochondrial protein synthesis, whilst it has no effect on mt-tRNALeu(UUR) steady-state levels and aminoacylation. Despite the complete recovery of cell viability and the increase in mitochondrial translation, Cterm-overexpressing cybrids were not able to recover bioenergetic competence. These data suggest that, in our MELAS cell model, the beneficial effect of Cterm may be mediated by factors that are independent of the mitochondrial bioenergetics.


2021 ◽  
Author(s):  
Blase Matthew LeBlanc ◽  
Rosamaria Yvette Moreno ◽  
Edwin Escobar ◽  
Mukesh Kumar Venkat Ramani ◽  
Jennifer S Brodbelt ◽  
...  

RNA polymerase II (RNAP II) is one of the primary enzymes responsible for expressing protein-encoding genes and some small nuclear RNAs. The enigmatic carboxy-terminal domain (CTD) of RNAP II and...


2008 ◽  
Vol 8 (1) ◽  
pp. 5-12 ◽  
Author(s):  
Thomas Kernebeck ◽  
Stefan Pflanz ◽  
Peter C. Heinrich ◽  
Axel Wollmer ◽  
Joachim Grötzinger ◽  
...  

RSC Advances ◽  
2015 ◽  
Vol 5 (98) ◽  
pp. 80434-80440 ◽  
Author(s):  
Saihui Zhang ◽  
Yantao Shi ◽  
Wei Wang ◽  
Zhi Yuan

Association between zinc(ii)-dipicolylamine appended beta-cyclodextrin and CTD (carboxy-terminal domain of RNA polymerase II) peptides with different phosphorylation patterns was studied by ITC and NMR.


2009 ◽  
Vol 83 (19) ◽  
pp. 10016-10027 ◽  
Author(s):  
Melissa P. Stropes ◽  
Olivia D. Schneider ◽  
William A. Zagorski ◽  
Jeanette L. C. Miller ◽  
William E. Miller

ABSTRACT The human cytomegalovirus (HCMV)-encoded G-protein-coupled receptor (GPCR) US28 is a potent activator of a number of signaling pathways in HCMV-infected cells. The intracellular carboxy-terminal domain of US28 contains residues critical for the regulation of US28 signaling in heterologous expression systems; however, the role that this domain plays during HCMV infection remains unknown. For this study, we constructed an HCMV recombinant virus encoding a carboxy-terminal domain truncation mutant of US28, FLAG-US28/1-314, to investigate the role that this domain plays in US28 signaling. We demonstrate that US28/1-314 exhibits a more potent phospholipase C-β (PLC-β) signal than does wild-type US28, indicating that the carboxy-terminal domain plays an important role in regulating agonist-independent signaling in infected cells. Moreover, HMCV-infected cells expressing the US28/1-314 mutant exhibit a prolonged calcium signal in response to CCL5, indicating that the US28 carboxy-terminal domain also regulates agonist-dependent signaling. Finally, while the chemokine CX3CL1 behaves as an inverse agonist or inhibitor of constitutive US28 signaling to PLC-β, we demonstrate that CX3CL1 functions as an agonist with regard to US28-stimulated calcium release. This study is the first to demonstrate that the carboxy terminus of US28 controls US28 signaling in the context of HCMV infection and indicates that chemokines such as CX3CL1 can decrease constitutive US28 signals and yet simultaneously promote nonconstitutive US28 signals.


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