Dynamin-like proteins in Trypanosoma brucei: A division of labour between two paralogs?

PLoS One. 2017 May 8;12(5):e0177200. doi: 10.1371/journal.pone.0177200. eCollection 2017.

Abstract

Dynamins and dynamin-like proteins (DLPs) belong to a family of large GTPases involved in membrane remodelling events. These include both fusion and fission processes with different dynamin proteins often having a specialised function within the same organism. Trypanosoma brucei is thought to have only one multifunctional DLP (TbDLP). While this was initially reported to function in mitochondrial division only, an additional role in endocytosis and cytokinesis was later also proposed. Since there are two copies of TbDLP present in the trypanosome genome, we investigated potential functional differences between these two paralogs by re-expressing either protein in a TbDLP RNAi background. These paralogs, called TbDLP1 and TbDLP2, are almost identical bar a few amino acid substitutions. Our results, based on cell lines carrying tagged and RNAi-resistant versions of each protein, show that overexpression of TbDLP1 alone is able to rescue the observed endocytosis and growth defects in the mammalian bloodstream form (BSF) of the parasite. While TbDLP2 shows no rescue in our experiments in BSF, this might also be due to lower expression levels of the protein in this life stage. In contrast, both TbDLP proteins apparently play more complementary roles in the insect procyclic form (PCF) since neither TbDLP1 nor TbDLP2 alone can fully restore wildtype growth and morphology in TbDLP-depleted parasites.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Line
  • Dynamins / chemistry
  • Dynamins / genetics
  • Dynamins / metabolism*
  • Protozoan Proteins / chemistry
  • Protozoan Proteins / genetics
  • Protozoan Proteins / metabolism*
  • RNA Interference
  • Sequence Homology, Amino Acid
  • Trypanosoma brucei brucei / metabolism*

Substances

  • Protozoan Proteins
  • Dynamins

Grants and funding

This work was supported by the Grant Agency of the Czech Republic (grant number: 15-21974S; https://gacr.cz/en/) to JL and (grant number: 17-24036S; https://gacr.cz/en/) to HH, Bioglobe grant CZ.1.07/2.3.00/30.0006 (http://alfa.bc.cas.cz/en/Postdok-BIOGLOBE/) to JL and CB and the European Research Council (grant number: CZ LL1601; https://erc.europa.eu/) to JL. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.