Nuclear mRNA export requires specific FG nucleoporins for translocation through the nuclear pore complex

Area of Science:

• Cell Biology
• Molecular Biology
• Biochemistry

Background:

• Nuclear pore complexes (NPCs) mediate transport of molecules between the nucleus and cytoplasm.
• NPC proteins with phenylalanine-glycine (FG) repeat domains are crucial for this transport.
• Specialized transport receptors bind FG domains to facilitate cargo movement.

Purpose of the Study:

• To investigate whether different transport receptors preferentially interact with specific FG domains within intact NPCs.
• To identify the functional roles of individual FG domains in nuclear transport processes.
• To elucidate the structural requirements for efficient messenger RNA (mRNA) export.

Main Methods:

• Utilized a large-scale deletion strategy in Saccharomyces cerevisiae to create minimal pore (mmp) mutants lacking specific FG domains.
• Compared messenger RNA (mRNA) export and protein import efficiencies in these mmp mutants.
• Analyzed the impact of FG domain deletions on NPC translocation.

Main Results:

• Identified unique subsets of mmp mutants with defects in specific transport receptors, indicating distinct NPC translocation routes.
• Demonstrated that messenger RNA (mRNA) export requires two specific NPC substructures: one on the nuclear face and one in the central core.
• Pinpointed distinct regulatory steps in mRNA export influencing NPC translocation efficiency.

Conclusions:

• Multiple functionally independent NPC translocation routes exist for different transport receptors.
• Specific FG domains and NPC substructures are critical for regulated mRNA export.
• This research provides a global analysis of FG domain requirements in nuclear transport.