Proximity proteomics in a marine diatom reveals a putative cell surface-to-chloroplast iron trafficking pathway
- University of California, Berkeley, United States
- University of California San Diego, United States
- J. Craig Venter Institute, United States
- National Center for Microscopy and Imaging Research, University of California San Diego, United States
- Czech Academy of Sciences, Czech Republic
- J Craig Venter Institute, United States
Abstract
Iron is a biochemically critical metal cofactor in enzymes involved in photosynthesis, cellular respiration, nitrate assimilation, nitrogen fixation, and reactive oxygen species defense. Marine microeukaryotes have evolved a phytotransferrin-based iron uptake system to cope with iron scarcity, a major factor limiting primary productivity in the global ocean. Diatom phytotransferrin is endocytosed, however proteins downstream of this environmentally ubiquitous iron receptor are unknown. We applied engineered ascorbate peroxidase APEX2-based subcellular proteomics to catalog proximal proteins of phytotransferrin in the model marine diatom Phaeodactylum tricornutum. Proteins encoded by poorly characterized iron-sensitive genes were identified including three that are expressed from a chromosomal gene cluster. Two of them showed unambiguous colocalization with phytotransferrin adjacent to the chloroplast. Further phylogenetic, domain, and biochemical analyses suggest their involvement in intracellular iron processing. Proximity proteomics holds enormous potential to glean new insights into iron acquisition pathways and beyond in these evolutionarily, ecologically, and biotechnologically important microalgae.
Data availability
All data generated or analyzed during this study are included in the manuscript and supporting files
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Phaeodactylum. tricornutum genomic databasePhaeodactylum tricornutum annotation 3 (Phatr3).
Article and author information
Author details
Andrew Ellis Allen
Funding
Gordon and Betty Moore Foundation (GBMF3828)
- Andrew Ellis Allen
Gordon and Betty Moore Foundation (GBMF5006)
- Andrew Ellis Allen
National Science Foundation (NSF-OCE-1756884)
- Andrew Ellis Allen
National Science Foundation (NSF-MCB-1818390)
- Andrew Ellis Allen
Biological and Environmental Research (DE-SC0018344)
- Andrew Ellis Allen
Gordon and Betty Moore Foundation (GBMF4958)
- Jernej Turnšek
National Institutes of Health (1F31ES030613-01)
- John K Brunson
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Copyright
© 2021, Turnšek et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
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Proximity proteomics in a marine diatom reveals a putative cell surface-to-chloroplast iron trafficking pathway
eLife 10:e52770.
https://doi.org/10.7554/eLife.52770
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