Dissection of the Relationship Between RACK1 and Heterotrimeric G-Proteins in Arabidopsis
Bibliographic record
Abstract
Mammalian receptor for activated C kinase 1 (RACK1) is a versatile scaffold protein, playing regulatory roles in multiple signal transduction pathways. Moreover, RACK1 interacts with the heterotrimeric G-proteins (G-proteins) and regulates some specific functions of Gbetagamma. Although the protein sequences of both RACK1 and G-proteins are highly conserved in Arabidopsis, their relationship remains elusive. Here we provide genetic and biochemical evidence that Arabidopsis RACK1 and G-proteins may act through a mechanism that is distinct from their counterparts in mammals. Loss-of-function alleles of RACK1A (the most abundantly expressed RACK1 gene in Arabidopsis) do not appear to share morphological and developmental phenotypes with loss-of-function alleles of GPA1 (encoding the sole Galpha in Arabidopsis) or AGB1 (encoding the sole Gbeta in Arabidopsis). The analysis of gpa1 rack1a and agb1 rack1a double mutants suggested that the effect of RACK1A on morphological and developmental traits may occur independently of the presence or absence of the G-protein subunits. Although both RACK1A and G-protein subunits are negative regulators of ABA responses in the ABA inhibition of early seedling development, an additive ABA hypersensitivity was observed in gpa1 rack1a and agb1 rack1a double mutants. Biochemical analysis suggested that unlike their counterparts in mammals, RACK1 may not physically interact with AGB1. Taken together, these findings revealed some fundamental differences in the relationship of RACK1 and G-proteins between Arabidopsis and mammals.
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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".