Related Experiment Video
Updated: Jun 12, 2026
09:02
Validation of a Mouse Model to Disrupt LINC Complexes in a Cell-specific Manner
Published on: December 10, 2015
Nucleoporin Nup98: a gatekeeper in the eukaryotic kingdoms
Masaaki Iwamoto1, Haruhiko Asakawa, Yasushi Hiraoka
1Kobe Advanced ICT Research Center, National Institute of Information and Communications Technology, Japan.
Summary
Nucleoporin Nup98, crucial for nuclear pore complex function and mRNA export, shows diverse evolution across eukaryotic kingdoms. Its specialized roles in ciliates highlight unique nuclear transport mechanisms.
Area of Science:
- Cell Biology
- Molecular Biology
- Evolutionary Biology
Background:
- Nucleoporin Nup98 is a key component of the nuclear pore complex, essential for nuclear-cytoplasmic transport, including mRNA export.
- Nup98 possesses a Gly-Leu-Phe-Gly (GLFG) repeat domain and is implicated in gene expression, mitotic checkpoint regulation, and pathogenesis.
- This protein is conserved in fungi and animals (Opisthokonta) but exhibits significant diversity in other eukaryotic supergroups.
Purpose of the Study:
- To review the diverse functions of Nup98 within eukaryotic organisms.
- To explore the evolutionary trajectory of Nup98 across different eukaryotic kingdoms.
- To highlight the specialized roles of Nup98 orthologs, particularly in ciliates.
Main Methods:
- Literature review of existing studies on Nup98.
- Comparative analysis of Nup98 orthologs across eukaryotic supergroups.
- Focus on Nup98 function and evolution.
Main Results:
- Nup98 plays conserved roles in nuclear-cytoplasmic transport and other cellular processes.
- Significant diversity exists in Nup98 orthologs outside the Opisthokonta supergroup.
- Ciliates exhibit nucleus-specific Nup98 variants involved in selective transport.
Conclusions:
- Nup98 is a versatile protein with critical roles in eukaryotic cell biology.
- The evolution of Nup98 reflects the diversification of nuclear pore complex functions across eukaryotes.
- Nup98's specialized forms, like those in ciliates, offer insights into nucleus-specific transport mechanisms.
Related Concept Videos
01:45Regulation of Nuclear Protein Sorting
Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
01:34Nuclear Protein Sorting
Nuclear protein sorting is the selective trafficking of histones, polymerases, gene regulatory proteins into the nucleus and exporting RNAs and ribosomes to the cytosol. It is a tightly controlled process that regulates gene expression within a cell.
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
Proteins targeted to the nucleus carry nuclear localization signals or NLS recognized by import receptors in the cytosol. Similarly, proteins with nuclear export signals are recognized by export receptors. Import and export receptors are...
01:42Nuclear Export
The nucleus restricts several proteins within and allows others to pass. The restricted proteins possess a nuclear retention sequence or NRS, anchoring them to the nuclear lamins and preventing their transport to the cytosol. The non-restricted proteins, after their synthesis, are transported to their site of action, such as the cytosol or other organelles, with the help of nuclear export signals or NES.
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
NES are of three types- the canonical 10-residue long leucine-rich signal and other...
02:31Nuclear Export of mRNA
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
02:31Nuclear Export of mRNA
Before mRNAs are exported to the cytoplasm, it is crucial to check each mRNA for structural and functional integrity. Eukaryotic cells use several different mechanisms, collectively known as mRNA surveillance, to look for irregularities in mRNAs. Irregular or aberrant mRNA are rapidly degraded by various enzymes. If a defective mRNA escapes the surveillance, it would be translated into a protein which would either be non-functional or not function properly. One of the primary irregularities in...
01:46Nuclear Localization Signals and Import
Proteins targeted to the nucleus carry short stretches of amino acid sequences called the nuclear localization signal or NLS. Classical nuclear localization signals are of two types: monopartite and bipartite NLS. Monopartite classical NLS (cNLS) consists of a single cluster of 4-8 amino acids. Bipartite cNLS consists of two clusters of 2-3 amino acids and a 9-12 residue long proline-rich linker bridging the two clusters. Signal clusters are rich in positively charged amino acids such as...