Phosphorylation of the lipid droplet localized glycerol‑3‑phosphate acyltransferase Gpt2 prevents a futile triacylglycerol cycle in yeast
Bibliographic record
Abstract
The proteome of lipid droplets, storage compartments of triacylglycerols (TAGs), comprises TAG synthesizing and TAG degrading enzymes. Thus, to prevent a futile cycle the activity of enzymes catalyzing key steps in TAG turnover has to be strictly coordinated. The first and committed reaction of TAG synthesis is catalyzed by a glycerol‑3‑phosphate acyltransferase (GPAT). Here we demonstrate that in the model organism yeast the lipid droplet associated GPAT Gpt2 requires phosphorylation at a conserved motif to prevent a futile TAG cycle. Phosphorylation deficiency at the conserved motif increases the enzyme activity of Gpt2 and consequently enhances TAG synthesis. In proliferating cells the phosphorylation deficient GPAT-form contributes to TAG metabolism similar to control. However, during lipolysis the increased activity of phosphorylation deficient Gpt2 causes a constant TAG level by using TAG-released fatty acids as substrate for TAG synthesis. These data strongly indicate that phosphorylation of Gpt2 at a conserved motif plays a critical role in coordinating the synthesis and degradation of TAGs.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".