NUP159 Antibody

What is NUP159 and what cellular functions does it have?

NUP159 (also known as Nucleoporin Nup155, KIAA0791, or Nuclear pore complex protein Nup155) is an essential component of the nuclear pore complex (NPC). It plays critical roles in:

• Binding and translocating proteins during nucleocytoplasmic transport

• Essential for embryogenesis

• mRNA export from the nucleus to the cytoplasm

In yeast, Nup159p (the yeast homolog) has been identified as a 159 kDa protein that localizes to the cytoplasmic side of the nuclear pore complex, as demonstrated by immunogold electron microscopy . It contains multiple domains including coiled-coil regions near the C-terminus that are essential for cell viability .

What applications can NUP159 antibodies be used for?

Based on validated research applications, NUP159 antibodies can be used for:

• Western blotting (WB): Effective for detecting NUP159 in whole cell lysates from various cell lines including 293T, HeLa, Jurkat, and NIH 3T3 cells

• Immunoprecipitation (IP): Useful for studying protein-protein interactions, such as the interaction between NUP159 and other nucleoporins

• Immunofluorescence microscopy: For visualizing NPC distribution and localization in fixed cells

• Co-immunoprecipitation assays: For investigating novel interactions, such as between NUP159 and the Bfa1/Bub2 complex

For example, immunofluorescence with specific NUP159 antibodies typically reveals a punctate nuclear rim staining pattern characteristic of nucleoporins .

What species reactivity should I expect from NUP159 antibodies?

Commercial NUP159 antibodies show varying species reactivity:

When selecting an antibody for cross-species applications, verify sequence homology and consider preliminary validation experiments to confirm reactivity in your specific experimental system .

How can I optimize Western blot conditions for detecting NUP159?

Optimization of Western blot protocols for NUP159 detection requires careful consideration of several parameters:

Recommended protocol based on published research:

• Protein loading: Use 15-50 μg of whole cell lysate per lane

• Antibody concentration: For ab157104, use 0.1 μg/mL dilution

• Detection method: ECL technique provides good results

• Exposure time: Starting with 3 minutes is recommended

• Expected band size: For human NUP159, approximately 155 kDa

Sample preparation considerations:

• NUP159 is prone to degradation in protein extracts, resulting in several faster migrating bands besides the full-length protein

• Use protease inhibitors and keep samples cold during preparation

• For better preservation of NUP159, use protease-deficient strains when working with yeast models

What are the best fixation and permeabilization methods for immunofluorescence with NUP159 antibodies?

Based on successful protocols from the literature:

Method 1 (for mammalian cells):

• Fix cells with 3.7% formaldehyde

• Permeabilize with 0.1% Triton X-100 for 20 minutes at room temperature

• Block with 2% normal goat serum in PBS containing 1% BSA

• Wash with 0.1% Tween 20

Method 2 (for yeast cells):

• Fix cells with 3.7% formaldehyde

• Convert to spheroplasts using 300 mg/ml Zymolyase 100T

• Incubate overnight at 4°C with primary antibody

• Wash and incubate with appropriate fluorophore-conjugated secondary antibody

Images can be acquired using fluorescence microscopy with standard FITC filter sets (excitation 450-490 nm, emission 515-560 nm) .

How can I distinguish between true NUP159 signals and non-specific binding in co-immunoprecipitation experiments?

To ensure specificity in co-immunoprecipitation experiments involving NUP159:

• Essential controls:

  • Use IgG-only control lanes to identify non-specific binding to the beads

  • Include untagged strains or cell lines as negative controls

  • Compare bound and unbound (flow-through) fractions to assess pull-down efficiency

• Specific considerations for NUP159 experiments:

  • When using protein A-tagged constructs for immunoprecipitation, add 10% human serum to decrease non-specific cross-reactivity of antibodies with the protein A moiety

  • For co-immunoprecipitation of NUP159 with other proteins (e.g., Bfa1), be aware that residual background signals can sometimes be observed in control cells due to unspecific binding to magnetic beads

  • Verify interactions with alternative techniques such as BiFC (Bimolecular Fluorescence Complementation) assays

How can I use NUP159 antibodies to study the dynamics of nuclear pore complex assembly?

NUP159 antibodies can be valuable tools for studying NPC assembly and dynamics:

• Combined immunofluorescence approaches:

  • Co-stain with mAb414 (recognizes several FG-repeat nucleoporins) and antibodies specific to individual nucleoporins like NUP93, NUP107, or POM121

  • This allows detection of assembly intermediates that might only be positive for scaffold Nups but not yet for FG-repeat Nups

• Cell cycle-dependent studies:

  • Use temperature-sensitive mutants or cell synchronization methods to arrest cells at specific cell cycle stages

  • Compare NUP159 localization and interactions at different cell cycle points

  • For example, the interaction between NUP159 and Bfa1/Bub2 is cell cycle-regulated, being reduced in metaphase but strongly stimulated during anaphase

• Live cell imaging:

  • Use GFP-tagged nucleoporins (like GFP-Nup49p) to visualize NPC distribution in living cells

  • Treatment with protein synthesis inhibitors like cycloheximide can help differentiate between new NPC assembly and redistribution of existing NPCs

What is known about the interaction between NUP159 and Dbp5, and how can this be studied using antibodies?

The interaction between NUP159 and Dbp5 is critical for mRNA export:

• Structural basis of interaction:

  • The N-terminal domain (NTD) of NUP159 (residues 1-387) is necessary and sufficient for Dbp5 binding

  • NUP159-NTD specifically promotes the release of ADP from Dbp5, acting as a nucleotide exchange factor

  • This release activity is concentration-dependent and reaches optimal efficiency at a 1:1 Dbp5:NUP159 molar ratio

• Experimental approaches to study this interaction:

  • Nucleotide binding assays: Using radiolabeled nucleotides (14C-ADP) to monitor NUP159-mediated ADP release from Dbp5

  • Mutagenesis studies: Creating altered versions of NUP159 that lack Dbp5 binding (e.g., nup159DD or nup159VI) as negative controls

  • Immunoprecipitation: Using antibodies against NUP159 or Dbp5 to pull down the protein complex

• Functional consequences:

  • Mutants lacking the Dbp5 binding region show defects in mRNA export

  • The interaction is part of a cycle where NUP159 and Gle1-IP6 regulate Dbp5 by controlling its nucleotide-bound state

How can domain-specific antibodies help understand the function of different regions of NUP159?

Domain-specific antibodies are valuable tools for dissecting NUP159 function:

• Available domain-specific antibodies:

  • Antibodies against the repeat region (e.g., rat7#4 raised against the repeat region of Nup159p)

  • Antibodies against the carboxyl domain (e.g., rat7#5)

• Applications of domain-specific antibodies:

  • Structure-function analysis: Can be used to study mutants with specific domain deletions (e.g., nup159-ΔN lacking amino acids 1-456, or nup159-C containing only the C-terminal heptad repeat)

  • Protein localization: Different domains may show distinct subcellular localizations

  • Interaction mapping: Can help determine which domains interact with specific binding partners

• Research findings using domain-specific approaches:

  • The SAFG/PSFG repeat region in the central third of NUP159 is dispensable for growth

  • The coiled-coil regions near the C-terminus are essential for viability

  • The N-terminal third plays an important role in mRNA export

  • The C-terminal domain anchors NUP159 within the NPC through interactions with Nsp1p and Nup82p

What are common issues when using NUP159 antibodies and how can they be addressed?

When working with NUP159 antibodies, researchers frequently encounter these challenges:

• Protein degradation:

  • Issue: NUP159 is prone to degradation in protein extracts, resulting in multiple bands on Western blots

  • Solution: Use protease inhibitor cocktails, keep samples cold, reduce processing time, and consider using protease-deficient strains for yeast work

• Cross-reactivity with Protein A tags:

  • Issue: When using Protein A-tagged constructs, antibodies may cross-react with the tag

  • Solution: Add 10% human serum during incubation steps to decrease non-specific binding

• Background signal in co-immunoprecipitation:

  • Issue: Residual background signal in control samples due to unspecific binding to beads

  • Solution: Include proper controls, optimize wash conditions, and validate interactions with alternative methods like BiFC

• Epitope masking in fixed samples:

  • Issue: Some fixation methods may mask epitopes

  • Solution: Test different fixation and permeabilization protocols; formaldehyde fixation followed by Triton X-100 permeabilization works well for many NPC antibodies

How do I design appropriate controls for NUP159 immunofluorescence experiments?

Proper controls are essential for reliable NUP159 immunofluorescence:

• Negative controls:

  • Secondary antibody only (omit primary antibody)

  • Pre-immune serum at the same dilution as the primary antibody

  • Use of deletion mutants or knockdown cells where NUP159 is absent or reduced

• Positive controls:

  • Co-staining with mAb414 antibody, which recognizes several nucleoporins and gives a characteristic nuclear rim pattern

  • Use of GFP-tagged nucleoporins as reference markers for NPC localization

• Validation controls:

  • Temperature-shift experiments with conditional mutants (e.g., nup159-1) to confirm antibody specificity

  • Peptide competition assays where the immunizing peptide is pre-incubated with the antibody

• Technical considerations:

  • Document equivalent exposure conditions for all images

  • Include wild-type and mutant samples in the same experiment for direct comparison

What strategies can be used to distinguish between different nucleoporins in complex samples?

Distinguishing between different nucleoporins can be challenging due to their similar localization and sometimes overlapping molecular weights:

• Sequential immunoprecipitation:

  • First immunoprecipitate with antibodies against one nucleoporin

  • Then use the eluate for a second immunoprecipitation with antibodies against another nucleoporin

  • This approach can help identify specific subcomplexes

• Combinatorial immunofluorescence:

  • Use antibodies raised in different species to allow simultaneous detection

  • For example, combine rabbit anti-Nsp1p with guinea pig anti-Nup159p

  • This allows visualization of colocalization or distinct localization patterns

• Differential extraction techniques:

  • Some nucleoporins may be more readily extracted than others under specific conditions

  • For instance, peripheral nucleoporins versus scaffold nucleoporins

• Molecular weight discrimination:

  • Many nucleoporins have characteristic molecular weights (e.g., NUP159 at 159 kDa)

  • Use high-resolution SDS-PAGE gels (e.g., 8% polyacrylamide) for better separation

How can I use NUP159 antibodies to investigate the relationship between nuclear pore complexes and cell cycle regulation?

Recent research has revealed connections between NPCs and cell cycle regulation that can be studied using NUP159 antibodies:

• Cell cycle synchronization approaches:

  • Use of temperature-sensitive mutants (e.g., cdc13-1, cdc15-2, cdc20-3) to arrest cells at specific cell cycle stages

  • Chemical synchronization methods like alpha-factor (G1), hydroxyurea (S-phase), or nocodazole (metaphase)

  • After synchronization, analyze NUP159 localization, interactions, or modifications

• Investigation of specific interactions:

  • The Bfa1/Bub2 complex associates with NUP159 in a cell cycle-regulated manner

  • This interaction is reduced in metaphase-arrested cells but enhanced in anaphase-blocked cells

  • Co-immunoprecipitation assays with appropriate antibodies can track these dynamic interactions

• Correlation with cellular checkpoints:

  • NUP159 interactions can be studied in relation to spindle assembly checkpoint (SAC) activation

  • Experiments combining nocodazole treatment (activates SAC) with temperature-sensitive mutations provide insights into the interplay between nucleoporins and checkpoint mechanisms

• Quantitative analysis approaches:

  • Measure the efficiency of co-immunoprecipitation at different cell cycle stages

  • Use BiFC assays to visualize and quantify interactions in living cells during cell cycle progression

What novel interactions of NUP159 have been recently discovered?

Recent research has uncovered previously unknown interactions involving NUP159:

• Interaction with the Bfa1/Bub2 complex:

  • NUP159 associates with the Bfa1/Bub2 complex, which is a part of the spindle positioning checkpoint

  • This interaction is cell cycle-regulated and requires Bfa1/Bub2 localization to the spindle pole bodies (SPBs)

  • The interaction is specifically prevented during the initial stages of spindle positioning but promoted in anaphase

  • This association may facilitate the activity of a NUP159-dependent autophagic pathway

• Interaction with the Dyn2 protein:

  • Dyn2 is predominantly a homodimer that binds arrayed sites on NUP159

  • This binding promotes the parallel homodimerization of NUP159

  • Dyn2 recognizes a highly conserved QT motif in NUP159 while allowing sequence plasticity in flanking residues

  • Isothermal titration calorimetric analysis shows similar affinities (18 and 13 μM) for two different NUP159 target sites

• Interactions within the NUP159/Nsp1p/Nup82p subcomplex:

  • Detailed biochemical studies have mapped the domains involved in these interactions

  • The carboxyl-terminal domain of NUP159 interacts with both Nsp1p and Nup82p

  • The carboxyl-terminal domain of Nup82p is required for its interaction with Nsp1p but not for the interaction between NUP159 and Nsp1p

  • These interactions are critical for anchoring NUP159 at the cytoplasmic face of the NPC

How do mutations in NUP159 affect nuclear transport and what can antibodies reveal about these effects?

Studies using antibodies have provided insights into how NUP159 mutations affect nuclear transport:

• Effects on mRNA export:

  • The temperature-sensitive nup159-1/rat7-1 mutant shows rapid and dramatic nuclear accumulation of poly(A)+ RNA when shifted to restrictive temperature

  • This defect can be visualized using in situ hybridization techniques in conjunction with immunofluorescence using NUP159 antibodies

• Differential effects on import versus export:

  • Interestingly, nup159-1 and nup82Δ108 mutant strains show little to no defect in nuclear protein import and protein export despite severe mRNA export defects

  • This suggests functional specificity in how different nucleoporins contribute to distinct transport pathways

  • Antibody studies can help track the presence/absence of nucleoporins in these mutants

• Structural consequences of mutations:

  • Immunofluorescence microscopy using antibodies against NUP159 shows that in nup82Δ108 cells grown at 37°C, NUP159 is delocalized from the NPC

  • This occurs because the Nup82Δ108p mutant protein becomes degraded at this temperature

  • These findings suggest that Nup82p acts as a docking site for a core complex containing NUP159 and Nsp1p

• Domain-specific effects:

  • Structure-function analysis using domain-specific antibodies revealed that:

    • Deletion of the repeat region has minimal phenotypic effects

    • Mutations in the C-terminal coiled-coil region severely affect cell viability

    • Different N-terminal deletions result in distinct effects on NPC distribution

What are the current techniques for studying NUP159 involvement in nucleocytoplasmic transport?

Researchers employ several sophisticated techniques to study NUP159's role in nucleocytoplasmic transport:

• In vivo transport assays:

  • For protein import: Using reporters like Mig1p-GFP-LacZ that shuttle into the nucleus in response to glucose

  • For protein export: Using NLS-GFP2-NES reporter proteins

  • For mRNA export: Fluorescence in situ hybridization with oligo(dT) probes to detect poly(A)+ RNA

• Live-cell imaging approaches:

  • GFP-tagged nucleoporins to monitor NPC distribution and dynamics

  • Fluorescent cargo molecules to track transport kinetics in real-time

  • Photobleaching techniques (FRAP, FLIP) to measure mobility and turnover rates

• Biochemical reconstitution:

  • In vitro systems using purified components to study specific steps in the transport process

  • For example, reconstituting the Dbp5 cycle with purified Dbp5, NUP159-NTD, and Gle1-IP6 to study the mechanism of mRNA export

• Genetic approaches:

  • Temperature-sensitive mutants

  • Domain deletion/substitution analysis

  • Synthetic genetic interactions to identify functional relationships with other transport factors

• Structural studies:

  • X-ray crystallography of NUP159 complexes, such as the Dyn2-NUP159 complex

  • These provide molecular insights into how NUP159 mediates interactions within the NPC

What is the current understanding of the role of NUP159 in disease processes?

While the search results don't directly address NUP159's role in diseases, the fundamental importance of nucleocytoplasmic transport in cellular homeostasis suggests potential disease implications:

• Developmental disorders:

  • NUP159 is described as "essential for embryogenesis"

  • Disruptions in nuclear pore complexes have been linked to various developmental disorders

• Cancer biology:

  • The interaction between NUP159 and cell cycle regulators like the Bfa1/Bub2 complex suggests potential roles in cell proliferation control

  • Alterations in nuclear transport have been implicated in cancer progression

• Neurodegenerative diseases:

  • Nucleocytoplasmic transport defects are emerging as important contributors to neurodegenerative diseases

  • NUP159's role in mRNA export may be particularly relevant since RNA metabolism is often disrupted in these conditions

• Viral infections:

  • Many viruses interact with or manipulate the nuclear pore complex during their life cycle

  • Understanding NUP159 function may provide insights into host-pathogen interactions

Research tools including specific antibodies against NUP159 and its interacting partners will be essential for further exploring these potential disease connections.