Dataset Information

Quantitative proximity proteomics suggests a phytotransferrin-mediated cell surface-to-chloroplast iron trafficking axis in marine diatoms

ABSTRACT: Iron is a biochemically critical metal cofactor in enzymes involved in photosynthesis, 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 internalized via endocytosis, 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 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.

INSTRUMENT(S): Orbitrap Fusion Lumos

ORGANISM(S): Phaeodactylum Tricornutum (strain Ccap 1055/1)

TISSUE(S): Photosynthetic Cell

SUBMITTER: Jernej Turnsek

LAB HEAD: Andrew Ellis Allen

PROVIDER: PXD018022 | Pride | 2021-03-02

REPOSITORIES: Pride

ACCESS DATA

Dataset's files

Source:

			Action	DRS
	Turnsek_et_al_10plex_3h_L05993.mzIdentML	Mzid
	Turnsek_et_al_10plex_3h_L05993.mzXML	Mzxml
	Turnsek_et_al_10plex_3h_L05993.raw	Raw
	Turnsek_et_al_10plex_4h_L05991.mzIdentML	Mzid
	Turnsek_et_al_10plex_4h_L05991.mzXML	Mzxml

Items per page:

1 - 5 of 9

Publications

Proximity proteomics in a marine diatom reveals a putative cell surface-to-chloroplast iron trafficking pathway.

Turnšek Jernej J Brunson John K JK Viedma Maria Del Pilar Martinez MDPM Deerinck Thomas J TJ Horák Aleš A Oborník Miroslav M Bielinski Vincent A VA Allen Andrew Ellis AE

eLife 20210216

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 appli ...[more]

PMID: 33591270

Similar Datasets

Project description:Oxidative Stress Protection and the Repair Response To Hydrogen Peroxide in the Hyperthermophilic Archaeon Pyrococcus furiosus Pyrococcus furiosus is a shallow marine, anaerobic archaeon that grows optimally at 100Â°C. Addition of H2O2 (0.5 mM) to a growing culture resulted in cessation of growth with a 2 hour lag before normal growth resumed. Whole genome transcriptional profiling revealed that the main response occurs within 30 min of peroxide addition, with the up-regulation of 62 open reading frames (ORFs), 36 of which are part of 10 potential operons. More than half of the up-regulated ORFs are of unknown function while some others encode proteins that are involved potentially in sequestering iron and sulfide, in DNA repair and in generating NADPH. This response is thought to involve primarily damage repair rather than protection, since cultures exposed to sub-toxic levels of H2O2 were not more resistant to the subsequent addition of H2O2 (0.5 â 5.0 mM). Consequently, there is little if any induced protective response to peroxide, rather, the organism maintains a constitutive protective mechanism involving high levels of oxidoreductase-type enzymes such as superoxide reductase, rubrerythrin and alkyl hydroperoxide reductase I. The related hyperthermophiles P. woesei and Thermococcus kodakaraensis were more sensitive to peroxide than P. furiosus, apparently due to the lack of several of its peroxide-responsive ORFs. Pyrococcus furiosus (DSM 3638) was grown at 95Â°C in a 20-liter fermentor using maltose as the carbon and energy source. An exponential-phase culture of P. furiosus that had undergone three successive transfers in the experimental medium was used to inoculate the 20-liter fermentor. The culture was shocked with 0.5 mM of hydrogen peroxide (H2O2) when cell density was in mid-exponential phase (~ 5.0 Â´ 107 cells/ml, as determined by direct microscopic cell count). To obtain RNA for microarray and for quantitative PCR (QPCR) analyses, samples (2 liter) were rapidly removed from the fermentor and cooled to 4Â°C. Total RNA was extracted using acid-phenol and stored at -80Â°C until needed. A total of 3 biological replicates in triplicate (3 copies on the same slide) was used in the data set.

Project description:2×10^7 HL60 cells were treated with 10 uM ATRA for 2 and 5 days, and conducted Hi-C to study the chromosomal architecture. Cells were fixed by 1% formaldehyde (v/v) for 15 min at room temperature (RT) with slowly rotation. Cells were lysed by 550 μl lysis buffer (500 μl 10 mM Tris-HCl pH 8.0, 10 mM NaCl, 0.2% Igepal CA-630 and 50 μl protease inhibitors) using a homogenizer, and harvested the chromatin at 5,000 rpm and washed twice. The pellet was added 1% SDS and incubated at 65 oC for 10 min, then quenched by Triton X-100. The chromatin was digested by 600 U MboI (NEB, Ipswich, USA) at 37 oC overnight. The next day, enzymes were inactivated by 10% SDS at 65 oC for 30 min, and the restriction fragment overhangs were filled in using biotin-14-dCTP and Klenow at 37 oC for 45 min, and the ligation was conducted in 7.61 ml ligation mix (745 μl 10% Triton X-100, 745 μl 10x ligation buffer (500 mM Tris-HCl pH 7.5, 100 mM MgCl2, 100 mM DTT), 80 μl 10 mg/ml BSA, 80 μl 100 mM ATP and 5.96 ml water) for 4 h at 16°C. The blunt-end Hi-C ligation was sonicated and pull down by streptavidin beads, then purified by ethanol. Hi-C library was prepared for paired ending sequencing using NEBNext® UltraTM DNA Library Prep Kit for Illuina® (NEB). For regular 3C ligation, after enzymes inactivation, 10 μl 1 U/μl T4 DNA ligase was added to incubate at 16°C overnight. The interaction was detected by qPCR using the specific 3C primers (Table 1) followed by DNA purification. Hi-C was conducted in PE-150. An iterative method for Hi-C mapping with initial length 30bp, if it fails to map uniquely, the next round of mapping for additional 20 bp continued, this procedure lasts until the full read length reaches 150bp. The Hi-C reads were mapped to the human reference genome (assembly GRCh38) using bowtie2 (v2.2.9). The reads mapped to the same restriction fragment, the reads less than 500bp and PCR duplicates were all removed. Hi-C contact maps were normalized using ICE.