Dataset Information

CP12 controls ribulose 1,5 bisphosphate recycling and carbon acquisition in Chlamydomonas reinhardtii

ABSTRACT: The small chloroplastic protein CP12 has multiple functions, including the regulation of enzymes in the Calvin-Benson-Bassham cycle. Here, we investigated its role in the acclimation of Chlamydomonas reinhardtii to varying CO2 availability. This alga has a CO2 concentrating mechanism that increases the supply of CO2 to ribulose-1,5-bisphosphate carboxylase/oxygenase (RuBisCO) and involves hallmarks such as HCO3- transporters and carbonic anhydrases as well as the condensation of RuBisCO within the pyrenoid via its interaction with a scaffold protein namedEssential Pyrenoid Component 1 (EPYC1). We showed that compared to the wild type, at high CO2, C. reinhardtii CP12 deletion mutants, or partially complemented mutants, have less phosphoribulokinase and ribulose-1,5-bisphosphate (RuBP) indicating that the regeneration of RuBP is regulated by CP12. In the absence of CP12, the expected relocation of RuBisCO towards the pyrenoid was not observed upon transition from high to very low CO2, contrary to WT cells. The CP12 deletion mutants are a unique example where the induction of CO2 concentrating mechanism hallmarks at very low CO2 was not accompanied by RuBisCO relocation. Altogether, these results suggest that CP12 contributes to the coordination between RuBP regeneration, RuBisCO location and CO2 acquisition.

INSTRUMENT(S):

ORGANISM(S): Chlamydomonas Reinhardtii

TISSUE(S): Photosynthetic Cell

SUBMITTER: Regine Lebrun

LAB HEAD: Hélène Launay

PROVIDER: PXD065761 | Pride | 2026-02-16

REPOSITORIES: Pride

ACCESS DATA

Dataset's files

Source:

			Action	DRS
	20240507_1001_DCP12_4_LCbis.raw	Raw
	20240507_1006_WT1_HCbis.raw	Raw
	20240507_1010_WT3_HCbis.raw	Raw
	20240507_1013_WT1_LCbis.raw	Raw
	20240507_1015_WT2_LCbis.raw	Raw

Items per page:

1 - 5 of 39

Similar Datasets

Project description:The slow kinetics and poor substrate specificity of the key photosynthetic CO2-fixing enzyme Rubisco have prompted the repeated evolution of Rubisco containing compartments known as pyrenoids in diverse algal lineages and carboxysomes in prokaryotes. Inside these compartments actively transported bicarbonate is converted into CO2 gas, which saturates the carboxylase with its substrate. Using co-immunoprecipitation experiments in Phaeodactylum tricornutum we have identified the Rubisco linker protein PYCO1. Similar to the green algal Rubisco linker protein EPYC1, PYCO1 is intrinsically disordered, possesses repeats and is positively charged at physiological pH. However, it possesses no sequence similarity to EPYC1, as expected for convergent evolution of a red Rubisco containing pyrenoid. Fluorescent PYCO1 fusion proteins localize as a rod shaped structure in the diatom chloroplast, consistent with the shape of the pyrenoid defined by transmission electron microscopy. To test the hypothesis that PYCO1 is the diatom pyrenoid scaffold we produced pure protein in Escherichia coli. Recombinant PYCO1 protein undergoes homotypic liquid liquid phase separation in a salt dependent manner. Diatom Rubisco specifically partitions into PYCO1 condensates. Heterotypic PYCO1-Rubisco condensates can bind up to three Rubisco hexadecamers per PYCO1 protein. Rubisco carboxylase function is unaffected in the condensates. PYCO1 is highly mobile in homotypic condensates. In contrast PYCO1 condensates saturated with diatom Rubisco have greatly reduced dynamics, with both PYCO1 and Rubisco becoming immobile. Consistently, FRAP experiments indicate that PYCO1 is not mobile in vivo. A combination of Cryo-electron microscopy and site-directed mutagenesis data show that the KWSP motif found in PYCO1 repeats binds to small subunits at the entrance of the Rubisco hexadecamer’s solvent channel. Analysis of mutant PYCO1 proteins show that both the “KWSP” tryptophan and another repeating tyrosine are essential for homotypic phase separation. We speculate that the unusual material properties of the PYCO1-Rubisco condensate are necessary to support the unusual non-spherical shape of the Phaeodactylum pyrenoid. Careful characterization of multiple diverse Rubisco condensates will strengthen translational approaches aiming to introduce pyrenoids and other metabolic condensates into new host organisms.

Project description:This experiment compares the transciptional changes in antigen specific murine CD8 T cells (P14 T cells) after exposure in vivo to dendritic cells (DC) pulsed with low dose cognate peptide (1uM KAVYNFATC), high dose cognate peptide (100uM KAVYNFATC) or no antigen. Splenic dendritic cells were freshly isolated, peptide pulsed, washed and then adoptively transferred s.c. to the right footpad of C57BL/6 hosts. After 18h, freshly isolated P14 CD8 T cells were labelled with CMFDA and adoptively transferred iv. Two hours after T cell transfer, anti-L selectin antibody was given iv. At 12 and 24 hours, recipients were sacrificed and The right popliteal LN was harvested at 12 or 24h post T cell transfer and a single cell suspension was created and stained with PE CD4, B220 and CD19 (dump channel). Cells were then sorted on a FacsARIA for being non-doublets, CMFDA positive and dump channel negative. This experiment compares the transciptional changes in antigen specific murine CD8 T cells (P14 T cells) after exposure in vivo to dendritic cells (DC) pulsed with low dose cognate peptide (1uM KAVYNFATC), high dose cognate peptide (100uM KAVYNFATC) or no antigen. Splenic dendritic cells were freshly isolated, peptide pulsed, washed and then adoptively transferred s.c. to the right footpad of C57BL/6 hosts. After 18h, freshly isolated P14 CD8 T cells were labelled with CMFDA and adoptively transferred iv. Two hours after T cell transfer, anti-L selectin antibody was given iv. At 12 and 24 hours, recipients were sacrificed and The right popliteal LN was harvested at 12 or 24h post T cell transfer and a single cell suspension was created and stained with PE CD4, B220 and CD19 (dump channel). Cells were then sorted on a FacsARIA for being non-doublets, CMFDA positive and dump channel negative. The experiment was conducted for 39 samples out of which 35 passsed transcriptional quality control tests. The phenotypic distribution for the 35 samples includes: (1) high dose (100uM KAVYNFATC ) cognate peptide pulsed samples harvested at 12h post T cell transfer: 6 biological replicates (2) high dose (100uM KAVYNFATC ) cognate peptide pulsed samples harvested at 24h post T cell transfer: 7 biological replicates (3) low dose (1uM KAVYNFATC) cognate peptide pulsed samples harvested at 12h post T cell transfer: 6 biological replicates (4) low dose (1uM KAVYNFATC) cognate peptide pulsed samples harvested at 24h post T cell transfer: 9 biological replicates (5) no antigen pulsed samples harvested at 12h post T cell transfer: 3 biological replicates (6) no antigen pulsed samples harvested at 24h post T cell transfer: 4 biological replicates.

Dataset Information

CP12 controls ribulose 1,5 bisphosphate recycling and carbon acquisition in Chlamydomonas reinhardtii

Dataset's files

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets