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Functional differentiation of Sec13 paralogues in the euglenozoan protists
Drahomíra Faktorová1,2, Kristína Záhonová1,3,4,5, Corinna Benz1
1Institute of Parasitology, Biology Centre, Czech Academy of Sciences, České Budějovice, Czech Republic.
Open Biology
|June 13, 2023
Summary
Euglenozoa possess two Sec13 proteins, unlike most eukaryotes. These paralogues, Sec13a and Sec13b, divide functions in protein transport and nutrient sensing, revealing distinct cellular organization in flagellates.
Area of Science:
- Cell Biology
- Molecular Evolution
- Protistology
Background:
- The β-propeller protein Sec13 is a conserved component of essential cellular machinery, including the COPII coat, nuclear pore complex (NPC), and Seh1-associated (SEA)/GATOR nutrient-sensing complex.
- Most eukaryotes possess a single Sec13 gene, implying conserved functions across these complexes.
Purpose of the Study:
- To investigate the Sec13 gene family in Euglenozoa, a diverse lineage of protists.
- To determine the functional and evolutionary divergence of Sec13 paralogues in this group.
Main Methods:
- Comparative genomics to identify Sec13 paralogues in Euglenozoa.
- Co-immunoprecipitation assays to analyze protein-protein interactions.
- Fluorescence microscopy for protein localization studies.
Main Results:
- Euglenozoa possess two distinct Sec13 paralogues, named Sec13a and Sec13b.
- In diplonemids, Sec13a localizes to the NPC and interacts with COPII components, while Sec13b interacts with Sec16 and SEA/GATOR complex members.
- Functional divergence is observed, with Sec13a involved in nuclear transport and anterograde protein trafficking, and Sec13b associated with nutrient sensing and autophagy pathways.
Conclusions:
- The presence of two Sec13 paralogues in Euglenozoa suggests a unique evolutionary trajectory for coatomer complexes within this lineage.
- The functional specialization of Sec13a and Sec13b highlights a distinct regulatory mechanism for cellular processes in euglenozoan flagellates.
- This finding offers insights into the diversification of fundamental eukaryotic cellular pathways.
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