Endosomal vesicle fusion machinery is involved with the contractile vacuole in Dictyostelium discoideum Manna, Paul Thomas Barlow, Lael D. Ramírez-Macías, Inmaculada .Herman, Emily K. Dacks, Joel B. Contractile vacuole Rab SNARE This work was supported by a Travel Grant from the Company of Biologists to L.D.B. and Discovery Grants from the Natural Sciences and Engineering Research Council of Canada (RES0021028, RES0043758, RES0046091) to J.B.D. During the time of this work J.B.D. was the CRC Tier II in Evolutionary Cell Biology. This project has received funding from the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement no. 101030247 to P.T.M. Contractile vacuoles (CVs), enigmatic osmoregulatory organelles, share common characteristics, such as a requirement for RAB11 and high levels of V-ATPase. These commonalities suggest a conserved evolutionary origin for the CVs with implications for understanding of the last common ancestor of eukaryotes and eukaryotic diversification more broadly. A taxonomically broader sampling of CV-associated machinery is required to address this question further. We used a transcriptomics-based approach to identify CV-associated gene products in Dictyostelium discoideum. This approach was first validated by assessing a set of known CV-associated gene products, which were significantly upregulated following hypo-osmotic exposure. Moreover, endosomal and vacuolar gene products were enriched in the upregulated gene set. An upregulated SNARE protein (NPSNB) was predominantly plasma membrane localised and enriched in the vicinity of CVs, supporting the association with this organelle found in the transcriptomic analysis. We therefore confirm that transcriptomic approaches can identify known and novel players in CV function, in our case emphasizing the role of endosomal vesicle fusion machinery in the D. discoideum CV and facilitating future work to address questions regarding the deep evolution of eukaryotic organelles. 2026-02-06T07:35:35Z 2026-02-06T07:35:35Z 2023-01-18 journal article Manna PT, Barlow LD, Ramirez-Macias I, Herman EK, Dacks JB. Endosomal vesicle fusion machinery is involved with the contractile vacuole in Dictyostelium discoideum. J Cell Sci. 2023 Jan 15;136(2):jcs260477. Epub 2023 Jan 18. PMID: 36546731. https://doi.org/10.1242/jcs.260477 https://hdl.handle.net/10481/110693 10.1242/jcs.260477 eng info:eu-repo/grantAgreement/EC/H2020/MSC/101030247 http://creativecommons.org/licenses/by-nc-nd/3.0/ open access Creative Commons Attribution-NonCommercial-NoDerivs 3.0 License The Company of Biologists