A novel protein, ubiquitous in marine phytoplankton, concentrates iron at the cell surface and facilitates uptake
Language English Country England, Great Britain Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't, Research Support, U.S. Gov't, Non-P.H.S.
PubMed
25557662
DOI
10.1016/j.cub.2014.12.004
PII: S0960-9822(14)01563-2
Knihovny.cz E-resources
- MeSH
- Species Specificity MeSH
- Phytoplankton metabolism MeSH
- Membrane Proteins metabolism MeSH
- Marine Biology MeSH
- Seawater chemistry MeSH
- Diatoms metabolism MeSH
- Gene Expression Profiling MeSH
- Protein Structure, Tertiary MeSH
- Iron metabolism pharmacokinetics MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Research Support, U.S. Gov't, Non-P.H.S. MeSH
- Names of Substances
- Membrane Proteins MeSH
- Iron MeSH
Numerous cellular functions including respiration require iron. Plants and phytoplankton must also maintain the iron-rich photosynthetic electron transport chain, which most likely evolved in the iron-replete reducing environments of the Proterozoic ocean [1]. Iron bioavailability has drastically decreased in the contemporary ocean [1], most likely selecting for the evolution of efficient iron acquisition mechanisms among modern phytoplankton. Mesoscale iron fertilization experiments often result in blooms dominated by diatoms [2], indicating that diatoms have adaptations that allow survival in iron-limited waters and rapid multiplication when iron becomes available. Yet the genetic and molecular bases are unclear, as very few iron uptake genes have been functionally characterized from marine eukaryotic phytoplankton, and large portions of diatom iron starvation transcriptomes are genes encoding unknown functions [3-5]. Here we show that the marine diatom Phaeodactylum tricornutum utilizes ISIP2a to concentrate Fe(III) at the cell surface as part of a novel, copper-independent and thermodynamically controlled iron uptake system. ISIP2a is expressed in response to iron limitation several days prior to the induction of ferrireductase activity, and it facilitates significant Fe(III) uptake during the initial response to Fe limitation. ISIP2a is able to directly bind Fe(III) and increase iron uptake when heterologously expressed, whereas knockdown of ISIP2a in P. tricornutum decreases iron uptake, resulting in impaired growth and chlorosis during iron limitation. ISIP2a is expressed by diverse marine phytoplankton, indicating that it is an ecologically significant adaptation to the unique nutrient composition of marine environments.
References provided by Crossref.org
Complex Response of the Chlorarachniophyte Bigelowiella natans to Iron Availability
Iron Uptake Mechanisms in Marine Phytoplankton
Endocytosis-mediated siderophore uptake as a strategy for Fe acquisition in diatoms
Carbonate-sensitive phytotransferrin controls high-affinity iron uptake in diatoms
Central role for ferritin in the day/night regulation of iron homeostasis in marine phytoplankton