Achromatopsia mutations target sequential steps of ATF6 activation
Bibliographic record
Abstract
Achromatopsia is an autosomal recessive disorder characterized by cone photoreceptor dysfunction. We recently identified activating transcription factor 6 (ATF6) as a genetic cause of achromatopsia. ATF6 is a key regulator of the unfolded protein response. In response to endoplasmic reticulum (ER) stress, ATF6 migrates from the ER to Golgi to undergo regulated intramembrane proteolysis to release a cytosolic domain containing a basic leucine zipper (bZIP) transcriptional activator. The cleaved ATF6 fragment migrates to the nucleus to transcriptionally up-regulate protein-folding enzymes and chaperones. ATF6 mutations in patients with achromatopsia include missense, nonsense, splice site, and single-nucleotide deletion or duplication changes found across the entire gene. Here, we comprehensively tested the function of achromatopsia-associated ATF6 mutations and found that they group into three distinct molecular pathomechanisms: class 1 ATF6 mutants show impaired ER-to-Golgi trafficking and diminished regulated intramembrane proteolysis and transcriptional activity; class 2 ATF6 mutants bear the entire ATF6 cytosolic domain with fully intact transcriptional activity and constitutive induction of downstream target genes, even in the absence of ER stress; and class 3 ATF6 mutants have complete loss of transcriptional activity because of absent or defective bZIP domains. Primary fibroblasts from patients with class 1 or class 3 ATF6 mutations show increased cell death in response to ER stress. Our findings reveal that human ATF6 mutations interrupt distinct sequential steps of the ATF6 activation mechanism. We suggest that increased susceptibility to ER stress-induced damage during retinal development underlies the pathology of achromatopsia in patients with ATF6 mutations.
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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) | 0.001 | 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".