Autoantibodies from patients with primary biliary cirrhosis preferentially react with the amino-terminal domain of nuclear pore complex glycoprotein gp210.

Patients with primary biliary cirrhosis frequently develop autoantibodies directed to gp210, a major glycoprotein of the nuclear pore complex. This protein contains a large glycosylated cisternal domain, a single transmembrane segment, and a short cytoplasmic tail. It has been previously shown that autoantibodies from primary biliary cirrhosis patients exclusively react with the cytoplasmic tail. We demonstrate that autoantibodies against gp210 recognize at least two different epitopes. 4 out of 12 anti-gp210 positive sera reacted with the fragment consisting of the cytoplasmic tail, and 8 sera targeted a novel epitope located within the large glycosylated lumenal domain. Moreover, our data prove that carbohydrate moieties are an essential part of this novel epitope. We propose, therefore, that future screening assays should be performed with antigens possessing both epitopes to detect all sera with anti-gp210 specificity.

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Autoantibodies from patients with primary biliary cirrhosis recognize a restricted region within the cytoplasmic tail of nuclear pore membrane glycoprotein Gp210.

Journal of Experimental Medicine ◽

10.1084/jem.178.6.2237 ◽

1993 ◽

Vol 178 (6) ◽

pp. 2237-2242 ◽

Cited By ~ 64

Author(s):

R E Nickowitz ◽

H J Worman

Keyword(s):

Amino Acids ◽

Amino Acid ◽

Primary Biliary Cirrhosis ◽

Antigenic Determinants ◽

Nuclear Pore ◽

Biliary Cirrhosis ◽

Amino Terminal ◽

Terminal Domain ◽

Carboxy Terminal ◽

Amino Terminal Domain

Patients with primary biliary cirrhosis (PBC) frequently have autoantibodies against a 210-kD integral glycoprotein of the nuclear envelope pore membrane. This protein, termed gp210, has a 1,783-amino acid amino-terminal domain located in the perinuclear space, a 20-amino acid transmembrane segment, and a 58-amino acid cytoplasmic carboxy-terminal tail. We now demonstrate that autoantibodies from 25 patients with PBC that recognize gp210 react with the cytoplasmic carboxy-terminal tail while none react with unmodified linear epitopes in the amino-terminal domain. The epitope(s) recognized by autoantibodies from all 25 patients is contained within a stretch of 15 amino acids. The recognized amino acid sequence is homologous to the protein products of the Escherichia coli mutY gene and Salmonella typhimurium mutB gene with an exact identity of six consecutive amino acids, suggesting that anti-gp210 antibodies may arise by molecular mimicry of bacterial antigenic determinants.

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Nic96p is required for nuclear pore formation and functionally interacts with a novel nucleoporin, Nup188p.

The Journal of Cell Biology ◽

10.1083/jcb.133.6.1141 ◽

1996 ◽

Vol 133 (6) ◽

pp. 1141-1152 ◽

Cited By ~ 77

Author(s):

U Zabel ◽

V Doye ◽

H Tekotte ◽

R Wepf ◽

P Grandi ◽

...

Keyword(s):

Nuclear Pore Complex ◽

Pore Formation ◽

Nucleocytoplasmic Transport ◽

Nuclear Pore ◽

Physical Interaction ◽

Nonpermissive Temperature ◽

Null Mutant ◽

Amino Terminal ◽

Allele Specific ◽

Amino Terminal Domain

The amino-terminal domain of Nic96p physically interacts with the Nsp1p complex which is involved in nucleocytoplasmic transport. Here we show that thermosensitive mutations mapping in the central domain of Nic96p inhibit nuclear pore formation at the nonpermissive temperature. Furthermore, the carboxyterminal domain of Nic96p functionally interacts with a novel nucleoporin Nup188p in an allele-specific fashion, and when ProtA-Nup188p was affinity purified, a fraction of Nic96p was found in physical interaction. Although NUP188 is not essential for viability, a null mutant exhibits striking abnormalities in nuclear envelope and nuclear pore morphology. We propose that Nic96p is a multivalent protein of the nuclear pore complex linked to several nuclear pore proteins via its different domains.

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Yeast N1e3p/Nup170p is required for normal stoichiometry of FG nucleoporins within the nuclear pore complex.

Molecular and Cellular Biology ◽

10.1128/mcb.16.5.2025 ◽

1996 ◽

Vol 16 (5) ◽

pp. 2025-2036 ◽

Cited By ~ 36

Author(s):

M A Kenna ◽

J G Petranka ◽

J L Reilly ◽

L I Davis

Keyword(s):

Nuclear Pore Complex ◽

Complementation Group ◽

Nuclear Localization Sequence ◽

Nuclear Pore ◽

Glutathione S Transferase ◽

Amino Terminal ◽

Localization Sequence ◽

Complementation Groups ◽

Amino Terminal Domain ◽

Yeast Homolog

The FG nucleoporins are a conserved family of proteins, some of which bind to the nuclear localization sequence receptor, karyopherin. Distinct members of this family are found in each region of the nuclear pore complex (NPC), spanning from the cytoplasmically disposed filaments to the distal end of the nuclear basket. Movement of karyopherin from one FG nucleoporin to the next may be required for translocation of substrates across the NPC. So far, nothing is known about how the FG nucleoporins are localized within the NPC. To identify proteins that interact functionally with one member of this family, the Saccharomyces cerevisiae protein Nup1p, we previously identified 16 complementation groups containing mutants that are lethal in the absence of NUP1 These mutants were referred to as nle (Nup-lethal) mutants. Mutants in the nle3/nlel7 complementation group are lethal in combination with amino-terminal nup1 truncation mutants, which we have previously shown to be defective for localization to the NPC. Here we show that NLE3 (which is allelic to NUP170) encodes a protein with similarity to the mammalian nucleoporin Nup155. We show that Nle3p coprecipitates with glutathione S-transferase fusions containing the amino-terminal domain of Nup1p. Furthermore, a deletion of Nle3p leads to changes in the stoichiometry of several of the XFXFG nucleoporins, including the loss of Nup1p and Nup2p. These results suggest that Nle3p plays a role in localizing specific FG nucleoporins within the NPC. The broad spectrum of synthetic phenotypes observed with the nle3delta mutant provides support for this model. We also identify a redundant yeast homolog that can partially substitute for Nle3p and show that together these proteins are required for viability.

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Primary biliary cirrhosis and the nuclear pore complex

Autoimmunity Reviews ◽

10.1016/j.autrev.2012.03.005 ◽

2012 ◽

Vol 11 (12) ◽

pp. 898-902 ◽

Cited By ~ 23

Author(s):

Carolina Duarte-Rey ◽

Dimitrios Bogdanos ◽

Chen-Yen Yang ◽

Krista Roberts ◽

Patrick S.C. Leung ◽

...

Keyword(s):

Primary Biliary Cirrhosis ◽

Nuclear Pore Complex ◽

Nuclear Pore ◽

Biliary Cirrhosis

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Autoantibodies against a 210kDa glycoprotein of the nuclear pore complex as a prognostic marker in patients with primary biliary cirrhosis

Journal of Gastroenterology and Hepatology ◽

10.1111/j.1440-1746.1998.01553.x ◽

1998 ◽

Vol 13 (3) ◽

pp. 257-265 ◽

Cited By ~ 83

Author(s):

SHINICHI ITOH ◽

TAKAFUMI ICHIDA ◽

TOSHIAKI YOSHIDA ◽

AKIHITO HAYAKAWA ◽

MORIAKI UCHIDA ◽

...

Keyword(s):

Primary Biliary Cirrhosis ◽

Prognostic Marker ◽

Nuclear Pore Complex ◽

Nuclear Pore ◽

Biliary Cirrhosis

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Enzymes of the SUMO Modification Pathway Localize to Filaments of the Nuclear Pore Complex

Molecular and Cellular Biology ◽

10.1128/mcb.22.18.6498-6508.2002 ◽

2002 ◽

Vol 22 (18) ◽

pp. 6498-6508 ◽

Cited By ~ 194

Author(s):

Hong Zhang ◽

Hisato Saitoh ◽

Michael J. Matunis

Keyword(s):

Nuclear Pore Complex ◽

Nucleocytoplasmic Transport ◽

Nuclear Pore ◽

Binding Studies ◽

Sumo Modification ◽

Amino Terminal ◽

Trimeric Complex ◽

Cytoplasmic Filaments ◽

Amino Terminal Domain

ABSTRACT SUMOs are small ubiquitin-related polypeptides that are reversibly conjugated to many nuclear proteins. Although the number of identified substrates has grown rapidly, relatively little is still understood about when, where, and why most proteins are modified by SUMO. Here, we demonstrate that enzymes involved in the SUMO modification and demodification of proteins are components of the nuclear pore complex (NPC). We show that SENP2, a SUMO protease that is able to demodify both SUMO-1 and SUMO-2 or SUMO-3 protein conjugates, localizes to the nucleoplasmic face of the NPC. The unique amino-terminal domain of SENP2 interacts with the FG repeat domain of Nup153, indicating that SENP2 associates with the nucleoplasmic basket of the NPC. We also investigated the localization of the SUMO conjugating enzyme, Ubc9. Using immunogold labeling of isolated nuclear envelopes, we found that Ubc9 localizes to both the cytoplasmic and the nucleoplasmic filaments of the NPC. In vitro binding studies revealed that Ubc9 and SUMO-1-modified RanGAP1 bind synergistically to form a trimeric complex with a component of the cytoplasmic filaments of the NPC, Nup358. Our results indicate that both SUMO modification and demodification of proteins may occur at the NPC and suggest a connection between the SUMO modification pathway and nucleocytoplasmic transport.

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Nucleoporins as Components of the Nuclear Pore Complex Core Structure and Tpr as the Architectural Element of the Nuclear Basket

Molecular Biology of the Cell ◽

10.1091/mbc.e04-03-0165 ◽

2004 ◽

Vol 15 (9) ◽

pp. 4261-4277 ◽

Cited By ~ 148

Author(s):

Sandra Krull ◽

Johan Thyberg ◽

Birgitta Björkroth ◽

Hans-Richard Rackwitz ◽

Volker C. Cordes

Keyword(s):

Nuclear Pore Complex ◽

Coiled Coil ◽

Radial Symmetry ◽

Nuclear Pore ◽

Amino Terminal ◽

Architectural Element ◽

Genes Encoding ◽

Complex Core ◽

Core Elements ◽

Amino Terminal Domain

The vertebrate nuclear pore complex (NPC) is a macromolecular assembly of protein subcomplexes forming a structure of eightfold radial symmetry. The NPC core consists of globular subunits sandwiched between two coaxial ring-like structures of which the ring facing the nuclear interior is capped by a fibrous structure called the nuclear basket. By postembedding immunoelectron microscopy, we have mapped the positions of several human NPC proteins relative to the NPC core and its associated basket, including Nup93, Nup96, Nup98, Nup107, Nup153, Nup205, and the coiled coil-dominated 267-kDa protein Tpr. To further assess their contributions to NPC and basket architecture, the genes encoding Nup93, Nup96, Nup107, and Nup205 were posttranscriptionally silenced by RNA interference (RNAi) in HeLa cells, complementing recent RNAi experiments on Nup153 and Tpr. We show that Nup96 and Nup107 are core elements of the NPC proper that are essential for NPC assembly and docking of Nup153 and Tpr to the NPC. Nup93 and Nup205 are other NPC core elements that are important for long-term maintenance of NPCs but initially dispensable for the anchoring of Nup153 and Tpr. Immunogold-labeling for Nup98 also results in preferential labeling of NPC core regions, whereas Nup153 is shown to bind via its amino-terminal domain to the nuclear coaxial ring linking the NPC core structures and Tpr. The position of Tpr in turn is shown to coincide with that of the nuclear basket, with different Tpr protein domains corresponding to distinct basket segments. We propose a model in which Tpr constitutes the central architectural element that forms the scaffold of the nuclear basket.

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A major glycoprotein of the nuclear pore complex is a membrane-spanning polypeptide with a large lumenal domain and a small cytoplasmic tail.

The EMBO Journal ◽

10.1002/j.1460-2075.1990.tb08267.x ◽

1990 ◽

Vol 9 (5) ◽

pp. 1495-1502 ◽

Cited By ~ 134

Author(s):

U.F. Greber ◽

A. Senior ◽

L. Gerace

Keyword(s):

Nuclear Pore Complex ◽

Cytoplasmic Tail ◽

Nuclear Pore ◽

Membrane Spanning ◽

Lumenal Domain

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The single transmembrane segment of gp210 is sufficient for sorting to the pore membrane domain of the nuclear envelope.

The Journal of Cell Biology ◽

10.1083/jcb.119.6.1441 ◽

1992 ◽

Vol 119 (6) ◽

pp. 1441-1449 ◽

Cited By ~ 75

Author(s):

R W Wozniak ◽

G Blobel

Keyword(s):

Nuclear Envelope ◽

Nuclear Pore Complex ◽

Immunofluorescence Microscopy ◽

Nuclear Pore ◽

Transmembrane Helices ◽

Wild Type ◽

Transmembrane Segment ◽

Membrane Domain ◽

3T3 Cells ◽

Type Mutant

The glycoprotein gp210 is located in the "pore membrane," a specialized domain of the nuclear envelope to which the nuclear pore complex (NPC) is anchored. gp210 contains a large cisternal domain, a single transmembrane segment (TM), and a COOH-terminal, 58-amino acid residue cytoplasmic tail (CT) (Wozniak, R. W., E. Bartnik, and G. Blobel. 1989. J. Cell Biol. 108:2083-2092; Greber, U. F., A. Senior, and L. Gerace. 1990. EMBO (Eur. Mol. Biol. Organ.) J. 9:1495-1502). To locate determinants for sorting of gp210 to the pore membrane, we constructed various cDNAs coding for wild-type, mutant, and chimeric gp210, and monitored localization of the expressed protein in 3T3 cells by immunofluorescence microscopy using appropriate antibodies. The large cisternal domain of gp210 (95% of its mass) did not reveal any sorting determinants. Surprisingly, the TM of gp210 is sufficient for sorting to the pore membrane. The CT also contains a sorting determinant, but it is weaker than that of the TM. We propose specific lateral association of the transmembrane helices of two proteins to yield either a gp210 homodimer or a heterodimer of gp210 and another protein. The cytoplasmically oriented tails of these dimers may bind cooperatively to the adjacent NPCs. In addition, we demonstrate that gp210 co-localizes with cytoplasmically dispersed nucleoporins, suggesting a cytoplasmic association of these components.

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