Mapping RNP-NUP interactions during nuclear export

• Applicant: Professorin Dr. Susanne Kramer
• Subject Area: Parasitology and Biology of Tropical Infectious Disease Pathogens ; Cell Biology
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 451084435

The compartmentalisation of hereditary information in the nucleus is the hallmark of eukaryotic evolution and necessitated the invention of a gateway allowing folded proteins and ribonucleoprotein particles (RNPs) to cross the nuclear envelope. The nuclear pore constitutes this gateway: it has adopted a bewildering complexity and is the largest protein complex of the cell. Current research is shifting the view of the nuclear pore as ‘simple channel’ to a more complex and dynamic transport platform with multiple cargo routes. We set out to shed light on nuclear transport mechanisms in the early branching eukaryote Trypanosoma brucei and have now established a cutting edge, reliable method-set to map interactions between nucleoporins and cargo, allowing to define routes of import and export for all macromolecules. We have combined different proximity labelling approaches with expansion microscopy to identify asymmetric pore components that direct transport. The data will allow to construct a new, more precise model of the trypanosome nuclear pore. Synergistically, our approach has identified many novel nuclear pore associated components inclusive positional information, which we will now interrogate for their functional roles to explore trypanosome specific adaptions of export control and mRNP remodeling. Of particular interest are the events at the nuclear basket (the pore structure that reaches into the nucleus and regulates export) and at the cytoplasmic site, where the newly exported RNP complex is remodeled. Despite the evolutionary distance, the basic structure of the nuclear pore is conserved, and some findings are likely transferable to other eukaryotes. Conversely, our approach will expose differences in nuclear transport between systems, advancing our view on nuclear pore evolution. Any mechanisms unique to the parasite are exploitable for drug development to combat trypanosomatid caused diseases like human African trypanosomiasis, Chagas and the leishmaniases.

• DFG Programme: Research Grants
• International Connection: Czech Republic
• Partner Organisation: Czech Science Foundation
• Cooperation Partner: Dr. Martin Zoltner