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NUP145 encodes a novel yeast glycine-leucine-phenylalanine-glycine (GLFG) nucleoporin required for nuclear envelope structure.

ABSTRACT: We have isolated and characterized the gene encoding a fourth yeast glycine-leucine-phenylalanine-glycine (GLFG) repeat nucleoporin with a calculated molecular mass of 145.3 kD, and therefore termed NUP145. The amino-terminal half of Nup145p is similar to two previously identified GLFG nucleoporins, Nup116p and Nup100p (Wente, S. R., M. P. Rout, and G. Blobel. 1992. J. Cell Biol. 119:705-723). A deletion/disruption in the amino-terminal half of NUP145 (nup145 delta N) had only a slight effect on cell growth at temperatures between 17 and 37 degrees C. However, immunofluorescence microscopy of nup145 delta N cells with antinucleoporin antibodies showed that the characteristic punctate nuclear staining normally seen in wild-type yeast cells was reduced, with the majority of the signal located in one or two intense spots at the nuclear periphery. Thin section electron microscopy analysis revealed the presence of what appeared to be successive herniations of the nuclear envelope forming grape-like structures at primarily one site on the nup145 delta N nuclei. These successive herniations contained numerous NPC-like structures, correlating to the limited bright patches of anti-nucleoporin immunofluorescence signal. In some cases the successive herniations were small. Occasionally, however, multi-lobulated nuclei were seen. We suggest that the ultrastructural phenotype of nup145 delta N cells is due to a defective interaction of nup145 delta N NPCs with the surrounding pore membrane domain of the nuclear envelope. We have also analyzed the synthetic lethal phenotypes among GLFG nucleoporin mutant alleles, and found that strains harboring nup116 and either nup100 or nup145 mutations were not viable. This, in combination with the morphological analysis, may reflect overlapping yet distinct roles for these three GLFG nucleoporins in NPC-nuclear envelope interactions.

SUBMITTER: Wente SR

PROVIDER: S-EPMC2120051 | biostudies-other | 1994 Jun

REPOSITORIES: biostudies-other

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NUP145 encodes a novel yeast glycine-leucine-phenylalanine-glycine (GLFG) nucleoporin required for nuclear envelope structure.

Wente S R SR Blobel G G

The Journal of cell biology 19940601 5

We have isolated and characterized the gene encoding a fourth yeast glycine-leucine-phenylalanine-glycine (GLFG) repeat nucleoporin with a calculated molecular mass of 145.3 kD, and therefore termed NUP145. The amino-terminal half of Nup145p is similar to two previously identified GLFG nucleoporins, Nup116p and Nup100p (Wente, S. R., M. P. Rout, and G. Blobel. 1992. J. Cell Biol. 119:705-723). A deletion/disruption in the amino-terminal half of NUP145 (nup145 delta N) had only a slight effect on ...[more]

PMID: 8195299

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Project description:Lentiviruses can infect non-dividing cells, and various cellular transport proteins provide crucial functions for lentiviral nuclear entry and integration. We previously showed that the viral capsid (CA) protein mediated the dependency on cellular nucleoporin (NUP) 153 during HIV-1 infection, and now demonstrate a direct interaction between the CA N-terminal domain and the phenylalanine-glycine (FG)-repeat enriched NUP153 C-terminal domain (NUP153(C)). NUP153(C) fused to the effector domains of the rhesus Trim5α restriction factor (Trim-NUP153(C)) potently restricted HIV-1, providing an intracellular readout for the NUP153(C)-CA interaction during retroviral infection. Primate lentiviruses and equine infectious anemia virus (EIAV) bound NUP153(C) under these conditions, results that correlated with direct binding between purified proteins in vitro. These binding phenotypes moreover correlated with the requirement for endogenous NUP153 protein during virus infection. Mutagenesis experiments concordantly identified NUP153(C) and CA residues important for binding and lentiviral infectivity. Different FG motifs within NUP153(C) mediated binding to HIV-1 versus EIAV capsids. HIV-1 CA binding mapped to residues that line the common alpha helix 3/4 hydrophobic pocket that also mediates binding to the small molecule PF-3450074 (PF74) inhibitor and cleavage and polyadenylation specific factor 6 (CPSF6) protein, with Asn57 (Asp58 in EIAV) playing a particularly important role. PF74 and CPSF6 accordingly each competed with NUP153(C) for binding to the HIV-1 CA pocket, and significantly higher concentrations of PF74 were needed to inhibit HIV-1 infection in the face of Trim-NUP153(C) expression or NUP153 knockdown. Correlation between CA mutant viral cell cycle and NUP153 dependencies moreover indicates that the NUP153(C)-CA interaction underlies the ability of HIV-1 to infect non-dividing cells. Our results highlight similar mechanisms of binding for disparate host factors to the same region of HIV-1 CA during viral ingress. We conclude that a subset of lentiviral CA proteins directly engage FG-motifs present on NUP153 to affect viral nuclear import.

Dataset Information

NUP145 encodes a novel yeast glycine-leucine-phenylalanine-glycine (GLFG) nucleoporin required for nuclear envelope structure.

Publications

NUP145 encodes a novel yeast glycine-leucine-phenylalanine-glycine (GLFG) nucleoporin required for nuclear envelope structure.

Similar Datasets

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