Oxysterol binding protein‐related protein 9 is required for Golgi organization and secretion
Bibliographic record
Abstract
Oxysterol binding protein (OSBP)‐related protein 9 (ORP9) is a member of the OSBP gene family implicated in ER/Golgi transport and lipid regulation. Due to alternate promoter start sites, ORP9 is expressed as a full length (ORP9L) and N‐terminal truncated variant (ORP9S). ORP9L localizes to the trans‐Golgi via pleckstrin homology (PH) domain by interaction with phosphatidylinositol‐4‐phosphate (PI‐4P). ORP9L and ORP9S also localize to ER compartments by interaction with vesicle associated‐membrane protein (VAMP)‐associated protein (VAP). Overexpression of ORP9L in CHO cells had no effect on growth, however overexpression of ORP9S caused significant inhibition. Growth inhibition appeared to be related to a seccretory defect. Enforced overexpression of ORP9S and ORP9L depletion by RNAi experiments resulted in fragmentation of the cis and trans elements of the Golgi. VSVG trafficking through the Golgi, measured by an endoH sensitivity, was disrupted by ORP9S expression and ORP9L depletion. Altered expression of ORP9S and ORP9L had no effect on 25‐hydroxycholesterol activated synthesis of sphingomyelin, suggesting that ORP9 does not have a role in OSBP regulation of CERT recruitment to the Golgi. These results indicate that ORP9L plays an important role in maintaining Golgi structure and secretion by interacting with PI‐4P, and ORP9S is a dominant negative regulator of ORP9L.
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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 | 0.000 |
| Insufficient payload (model declined to judge) | 0.002 | 0.002 |
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".