The Ca <sup>2+</sup> /Calcineurin-Regulated <i>cup</i> Gene Family in <i>Dictyostelium discoideum</i> and Its Possible Involvement in Development
Bibliographic record
Abstract
Changes in free intracellular Ca2+ are thought to regulate several major processes during Dictyostelium development, including cell aggregation and cell type-specific gene expression, but the mechanisms involved are unclear. To learn more about Ca2+ signaling and Ca2+ homeostasis in this organism, we used suppression subtractive hybridization to identify genes up-regulated by high extracellular Ca2+. Unexpectedly, many of the genes identified belong to a novel gene family (termed cup) with seven members. In vegetative cells, the cup genes were up-regulated by high Ca2+ but not by other ions or by heat, oxidative, or osmotic stress. cup induction by Ca2+ was blocked completely by inhibitors of calcineurin and protein synthesis. In developing cells, cup expression was high during aggregation and late development but low during the slug stage. This pattern correlates closely with reported levels of free intracellular Ca2+ during development. The cup gene products are highly homologous, acidic proteins possessing putative ricin domains. BLAST searches failed to reveal homologs in other organisms, but Western analyses suggested that Cup-like proteins might exist in certain other cellular slime mold species. Localization experiments indicated that Cup proteins are primarily cytoplasmic but become cell membrane-associated during Ca2+ stress and cell aggregation. When cup expression was down-regulated by antisense RNA, the cells failed to aggregate. However, this developmental block was overcome by partially up-regulating cup expression. Together, these results suggest that the Cup proteins in Dictyostelium might play an important role in stabilizing and/or regulating the cell membrane during Ca2+ stress and/or certain stages of development.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.000 | 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 teacher head, 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".