Alternative splicing of a novel diacylglycerol kinase in tomato leads to a calmodulin‐binding isoform
Bibliographic record
Abstract
Calmodulin is a regulatory protein activated during Ca2+ signalling. We have isolated a cDNA, designated LeCBDGK (Lycopersicon esculentum calmodulin-binding diacylglycerol kinase) encoding a novel calmodulin-binding protein with sequence similarity to diacylglycerol kinases from animals. Diacylglycerol kinases convert diacylglycerol to phosphatidic acid. We delineated the calmodulin-binding domain to approximately 25 residues near the C-terminus of LeCBDGK. We have also isolated a second diacylglycerol kinase cDNA, designated LeDGK1, identical to LeCBDGK, except that it lacks the calmodulin-binding domain. Both recombinant LeCBDGK and LeDGK1 were catalytically active in vitro. Anti-DGK antiserum detected two immunoreactive proteins associated with microsomal and plasma membrane fractions from cell suspensions. The higher molecular weight immunoreactive protein was also present in soluble extracts and bound to calmodulin-agarose in the presence of calcium, demonstrating that native LeCBDGK is a calmodulin-binding protein. In the presence of calcium, LeCBDGK associated with membrane cell fractions in vitro, but calmodulin antagonists disrupted this association, suggesting a possible role of calcium in the recruitment of LeCBDGK from soluble to membrane cell fractions. Native LeCBDGK and calmodulin co-immunoprecipitated from tomato soluble cell extracts, suggesting their interaction in vivo. The same gene encodes both LeCBDGK and LeDGK1 and the calmodulin-binding domain of LeCBDGK is encoded by a separate exon. Thus, alternative transcript splicing leads to calmodulin-binding and non-binding forms of diacylglycerol kinases in tomato. Possible roles of LeCBDGK and LeDGK1 in calcium and lipid signalling are discussed.
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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 | 0.001 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".