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Published on: October 28, 2022
Leishmania express a functional Cdc20 homologue
Tamar Listovsky1, Michael Brandeis, Dan Zilberstein
1Faculty of Biology, Technion-Israel Institute of Technology, Haifa 32000, Israel.
Abstract:
Our knowledge concerning the mechanisms of cell cycle regulation in organisms belonging to the Trypanosometidae family is limited. Leishmania donovani are parasitic protozoa that cause kala azar, a fatal form of visceral leishmaniasis in humans. Here we provide evidence that the L. donovani genome contains a Cdc20 homologue. Cdc20 is a regulator of the Anaphase Promoting Complex/Cyclosome (APC/C) that mediates ubiquitin-dependent proteasomal degradation of key cell cycle regulators in eukaryotes. We show that L. donovani Cdc20 protein (LdCdc20p) can complement a lack of yeast Cdc20 protein in Saccharomyces cerevisiae cells, validating the functionality of LdCdc20p. Furthermore, we demonstrate cyclic expression of LdCdc20p and that it contains an active RXXL destruction motif, a distinctive feature of proteins targeted for proteasomal degradation by APC/C. Finally, in line with the proteasome mediating LdCdc20p degradation, promastigotes exposed to proteasome inhibitor display elevated LdCdc20p levels. Taken together our data indicate that Leishmania regulate their cell cycle by ubiquitin-dependent proteasomal degradation mediated by the APC/C.
Insights
Leishmania donovani parasites utilize a Cdc20 protein to regulate their cell cycle. This protein controls the Anaphase Promoting Complex/Cyclosome (APC/C) for cell cycle progression.
Area of Science:
- Cell Biology
- Parasitology
- Molecular Biology
Background:
- Cell cycle regulation mechanisms in Trypanosometidae, including Leishmania donovani, are poorly understood.
- Leishmania donovani causes visceral leishmaniasis (kala azar), a severe human disease.
Purpose of the Study:
- To investigate the role of Cdc20 homologues in Leishmania donovani cell cycle regulation.
- To characterize the function and regulation of the L. donovani Cdc20 protein (LdCdc20p).
Main Methods:
- Bioinformatic analysis to identify a Cdc20 homologue in the L. donovani genome.
- Functional complementation assay using Saccharomyces cerevisiae lacking Cdc20.
- Analysis of LdCdc20p expression patterns and its destruction motif.
- Treatment of L. donovani promastigotes with proteasome inhibitors.
Main Results:
- A functional Cdc20 homologue (LdCdc20p) was identified in L. donovani.
- LdCdc20p successfully complemented the loss of Cdc20 in yeast, confirming its functionality.
- LdCdc20p exhibits cyclic expression and possesses an active RXXL destruction motif.
- Proteasome inhibition led to increased LdCdc20p levels in L. donovani promastigotes.
Conclusions:
- Leishmania donovani employs a Cdc20 protein to regulate its cell cycle.
- The Anaphase Promoting Complex/Cyclosome (APC/C) pathway, involving ubiquitin-dependent proteasomal degradation, is crucial for L. donovani cell cycle control.
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