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@mjmallenponce.bsky.social

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mjmallenponce.bsky.social @mjmallenponce.bsky.social · Apr 21

Glad to share our latest paper published in Science Advances! In this work, we show that #light and #CO₂ regulate #TOR through cytoplasmic #dihydroxyacetone phosphate (DHAP), revealing a key metabolic link in TOR [email protected] @science.org science.org/doi/10.1126/sciadv.adu1240

Dihydroxyacetone phosphate generated in the chloroplast mediates the activation of TOR by CO2 and light

Light and CO2 activate the eukaryotic TOR kinase through the central metabolite dihydroxyacetone phosphate.

science.org

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Reposted

CSIC @csic.es · Apr 30

🦠 Desvelan el mecanismo que permite a las células de las plantas integrar la luz y el CO2 para regular su crecimiento

🌿 Un estudio del #CSIC muestra cómo la activación de una proteína interviene en el crecimiento celular de organismos fotosintéticos

➡️http://tiny.cc/164i001

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mjmallenponce.bsky.social @mjmallenponce.bsky.social · Apr 23

thank you! 😊

mjmallenponce.bsky.social @mjmallenponce.bsky.social · Apr 23

Thank you!!! ☺️

Reposted

Takehiro A. Ozawa @tkozawa.bsky.social · Apr 22

Great work by Mallén-Ponce et al. (2025) on how they identified #dihydroxyacetone phosphate (DHAP) as a key metabolite regulating the activation of #PlantTOR in the green alga #Chlamydomonas reinhardtii in response to #CO2 availability and light signals 🌅.
@ibvf-sevilla.bsky.social #PlantScience ⬇️

Fig 3E. Proposed model for the regulation of target of rapamycin (TOR) activity by dihydroxyacetone phosphate (DHAP) in the model green alga Chlamydomonas reinhardtii.

Photosynthesis provides reducing power [NADPH (reduced form of nicotinamide adenine dinucleotide phosphate)] and energy [ATP (adenosine 5′-triphosphate)] for CO2 fixation and the biosynthesis of organic carbon compounds. DHAP is synthesized in the chloroplast and exported to the cytoplasm through the TPT3 transporter. The abundance of cytoplasmic DHAP is transmitted to TOR to modulate its activity.

Figure S3. Schematic diagram of central carbon metabolism in the model green alga Chlamydomonas reinhardtii.

The Calvin Benson Bassham (CBB), tricarboxylic acid (TCA) and glutamine synthetase-glutamate synthase (GS-GOGAT) cycles, gluconeogenesis, glycolysis and lipid synthesis are shown.

The effect of dihydroxyacetone (DHA), dimethyl-alpha-ketoglutarate (DMKG), L-methionine sulfoximine (MSX) or cerulenin on central metabolism is also shown.
The fatty acid synthase (FAS) inhibitor cerulenin and the GS inhibitor MSX are indicated with red lines whereas the metabolic input of DHA and DMKG as precursors of DHAP and AKG, respectively, are indicated with blue arrows. The DHAP chloroplast-to-cytosol transporter triose-phosphate-translocator 3 (TPT3) is shown in pink.

Enzyme abbreviations are as follows: PRK, phosphoribulokinase; RuBisCo, ribulose 1,5-bisphosphate carboxylase oxygenase; PGK, phosphoglucokinase; GAPDH, glyceraldehyde 3-phosphate dehydrogenase; TK, triokinase; TPI, triosephosphate isomerase; FAS: fatty acid synthase; GS, glutamine synthetase; GOGAT, glutamate synthase; TPT3, triose-phosphatetranslocator 3; PDH, pyruvate dehydrogenase; CS, citrate synthase; ACO, aconitase; IL, isocitrate lyase; IDH, isocitrate dehydrogenase; ADH, alphaketoglutarate dehydrogenase; SCS, succinyl-CoA-synthase; SDH, succinicdehydrogenase; Fum, fumarase; MDH, malate dehydrogenase; DAK1, dihydroxyacetone kinase 1. Metabolite abbreviations: DHAP, dihydroxyacetone phosphate; Ru5P, ribulose 5-phosphate; RuBP, ribulose 1,5-bisphosphate; 3- PGA, 3-phosphoglycerate; GAP, glyceraldehyde 3-phosphate; Glc, glucose; Glc1P, glucose 1-phosphate; Glc6P, glucose 6-phosphate; AKG, alphaketoglutarate.

Fig. 2. Effect of dihydroxyacetone (DHA), cerulenin, dimethyl-α-ketoglutarate (DMKG), or L-methionine sulfoximine (MSX) on TOR activity.

(A) Immunoblot (upper panel) of P-RPS6/ RPS6 in Chlamydomonas cells treated with 2 mM DHA (0, 15, 30, and 60 min) over the night part of the diurnal cycle. Relative abundance (lower panel) of DHAP in cells treated with 2 mM DHA (0, 15, 30, and 60 min).

(B) Immunoblot (upper panel) of P-RPS6/ RPS6 in cells treated with 20 μM cerulenin (0, 15, 30, and 60 min) over the day part of the diurnal cycle. Relative abundance (lower panel) of DHAP in cells treated with 20 μM cerulenin (0, 15, 30, and 60 min).

(C) Immunoblot (upper panel) of P-RPS6/ RPS6 in cells treated with 2 mM DMKG (0, 15, 30, and 60 min) over the night part of the diurnal cycle. Relative abundance (lower panel) of DHAP in cells under the same conditions. (D) Immunoblot (upper panel) of P-RPS6/ RPS6 and relative abundance (lower panel) of Gln in cells treated or not with 5 mM MSX for 2 hours over the night part of the diurnal cycle and then reilluminated for 30 min.

(E) Immunoblot (upper panel) of P-RPS6/ RPS6 and relative abundance (lower panel) of Gln and DHAP in cells treated or not with 5 mM MSX for 2 hours and then 2 mM DHA for 30 min over the day part of the diurnal cycle.

Coomassie brilliant blue–stained gels were used as a loading control. Chlamydomonas cells were grown in TP medium. Error bars correspond to SD from at least three biological replicates. Asterisks represent significant differences according to one-way ANOVA: ***P < 0.001; **P < 0.01; *P < 0.05; not significant, ≥0.05. The statistical analyses described apply to all statistical analyses in this figure (detailed in table S8). White and black bars indicate light and dark phases, respectively.

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mjmallenponce.bsky.social @mjmallenponce.bsky.social · Apr 21

Dihydroxyacetone phosphate generated in the chloroplast mediates the activation of TOR by CO2 and light

Light and CO2 activate the eukaryotic TOR kinase through the central metabolite dihydroxyacetone phosphate.

science.org

3 8 13

Reposted

Cecilia Blikstad @cblikstad.bsky.social · Apr 16

Come join us as a postdoc! We have an open position in biochemistry of cyanobacterial CO2 fixation focusing on regulation of carboxysome function! Please help me spread the word and welcome to apply! www.blikstadlab.org/open-positio...

Open positions

Postdoctoral scholar in biochemistry of cyanobacterial CO 2 fixation The Blikstad research group is searching for a postdoc to study fundamental principles of CO 2 fixation in cyanobacteria. Our...

www.blikstadlab.org

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