Analysis of the lipid body proteome of the oleaginous alga Lobosphaera incisa

Heike Siegler, Oliver Valerius, Till Ischebeck, Jennifer Popko, Nicolas J. Tourasse, Olivier Vallon, Inna Khozin-Goldberg, Gerhard H. Braus, Ivo Feussner

Research output: Contribution to journalArticlepeer-review

30 Scopus citations

Abstract

Background: Lobosphaera incisa (L. incisa) is an oleaginous microalga that stores triacylglycerol (TAG) rich in arachidonic acid in lipid bodies (LBs). This organelle is gaining attention in algal research, since evidence is accumulating that proteins attached to its surface fulfill important functions in TAG storage and metabolism. Results: Here, the composition of the LB proteome in L incisa was investigated by comparing different cell fractions in a semiquantitative proteomics approach. After applying stringent filters to the proteomics data in order to remove contaminating proteins from the list of possible LB proteins (LBPs), heterologous expression of candidate proteins in tobacco pollen tubes, allowed us to confirm 3 true LBPs: A member of the algal Major Lipid Droplet Protein family, a small protein of unknown function and a putative lipase. In addition, a TAG lipase that belongs to the SUGAR DEPENDENT 1 family of TAG lipases known from oilseed plants was identified. Its activity was verified by functional complementation of an Arabidopsis thaliana mutant lacking the major seed TAG lipases. Conclusions: Here we describe 3 LBPs as well as a TAG lipase from the oleaginous microalga L. incisa and discuss their possible involvement in LB metabolism. This study highlights the importance of filtering LB proteome datasets and verifying the subcellular localization one by one, so that contaminating proteins can be recognized as such. Our dataset can serve as a valuable resource in the identification of additional LBPs, shedding more light on the intriguing roles of LBs in microalgae.

Original languageEnglish
Article number98
JournalBMC Plant Biology
Volume17
Issue number1
DOIs
StatePublished - 6 Jun 2017

Keywords

  • Lipid bodies
  • Lipid droplets
  • Lobosphaera incisa
  • Nitrogen starvation
  • Oil bodies
  • Parietochloris
  • Proteome
  • TAG lipase

ASJC Scopus subject areas

  • Plant Science

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