Yeast nuclear pore complexes have a cytoplasmic ring and internal filaments

Area of Science:

• Cell Biology
• Structural Biology
• Biochemistry

Background:

• The nuclear pore complex (NPC) regulates macromolecule transport between the nucleus and cytoplasm.
• While vertebrate NPC structure is well-characterized, yeast NPC structural data is less comprehensive.
• Existing data suggest basic yeast NPC organization mirrors vertebrates but may differ in peripheral components.

Purpose of the Study:

• To investigate the structural composition of yeast nuclear pore complexes (NPCs).
• To compare the peripheral components of yeast NPCs with those of higher eukaryotes.
• To develop a revised structural model for yeast NPCs.

Main Methods:

• Field emission scanning electron microscopy (FESEM) was employed to visualize yeast NPC structure.
• Immuno-gold labeling was used to identify the localization of specific nucleoporins (Nup159p, Nup116p).
• Analysis of a Nup57p mutant assessed its role in NPC component stability.

Main Results:

• Yeast NPCs exhibit peripheral components similar to higher eukaryotes, including cytoplasmic and nucleoplasmic rings.
• A filamentous basket on the nucleoplasmic face and cytoplasmic filaments were observed.
• Nup159p localization to the cytoplasmic ring and Nup116p association with cytoplasmic filaments were suggested.
• A Nup57p mutant indicated its involvement in maintaining cytoplasmic NPC component stability.

Conclusions:

• Peripheral NPC components are conserved between yeast and higher eukaryotes.
• The study presents a revised structural model for yeast NPCs, emphasizing conserved features.
• Structural similarities suggest a common evolutionary basis for NPC organization across eukaryotes.