Higher Plant Calreticulins Have Acquired Specialized Functions in Arabidopsis
Bibliographic record
Abstract
BACKGROUND: Calreticulin (CRT) is a ubiquitous ER protein involved in multiple cellular processes in animals, such as protein folding and calcium homeostasis. Like in animals, plants have evolved divergent CRTs, but their physiological functions are less understood. Arabidopsis contains three CRT proteins, where the two CRTs AtCRT1a and CRT1b represent one subgroup, and AtCRT3 a divergent member. METHODOLOGY/PRINCIPAL FINDINGS: Through expression of single Arabidopsis family members in CRT-deficient mouse fibroblasts we show that both subgroups have retained basic CRT functions, including ER Ca2+-holding potential and putative chaperone capabilities. However, other more general cellular defects due to the absence of CRT in the fibroblasts, such as cell adhesion deficiencies, were not fully restored. Furthermore, in planta expression, protein localization and mutant analyses revealed that the three Arabidopsis CRTs have acquired specialized functions. The AtCRT1a and CRT1b family members appear to be components of a general ER chaperone network. In contrast, and as recently shown, AtCRT3 is associated with immune responses, and is essential for responsiveness to the bacterial Pathogen-Associated Molecular Pattern (PAMP) elf18, derived from elongation factor (EF)-Tu. Whereas constitutively expressed AtCRT1a fully complemented Atcrt1b mutants, AtCRT3 did not. CONCLUSIONS/SIGNIFICANCE: We conclude that the physiological functions of the two CRT subgroups in Arabidopsis have diverged, resulting in a role for AtCRT3 in PAMP associated responses, and possibly more general chaperone functions for AtCRT1a and CRT1b.
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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 | 0.001 |
| 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".