Expression of various scinderin domains in chromaffin cells indicates that this protein acts as a molecular switch in the control of actin filament dynamics and exocytosis
Bibliographic record
Abstract
Stimulation-induced chromaffin cell cortical F-actin disassembly allows the movement of vesicles towards exocytotic sites. Scinderin (Sc), a Ca2+-dependent protein, controls actin dynamics. Sc six domains have three actin, two PIP2 and two Ca2+-binding sites. F-actin severing activity of Sc is Ca2+-dependent, whereas Sc-evoked actin nucleation is Ca2+-independent. Sc domain role in secretion was studied by co-transfection of human growth hormone (hGH) reporter gene and green fluorescent protein (GFP)-fusion Sc constructs. Cells over-expressing actin severing Sc1-6 or Sc1-2 (first and second actin binding sites) constructs, increased F-actin disassembly and hGH release upon depolarization. Over-expression of nucleating Sc5-6, Sc5 or ScABP3 (third actin site) constructs decreased F-actin disassembly and hGH release upon stimulation. Over-expression of ScL5-6 or ScL5 (lack of third actin site) produced no changes. During secretion, actin sites 1 and 2 are involved in F-actin severing, whereas site 3 is responsible for nucleation (polymerization). Sc functions as a molecular switch in the control of actin (disassembly left arrow over right arrow assembly) and release (facilitation left arrow over right arrow inhibition). The position of the switch (severing left arrow over right arrow nucleation) may be controlled by [Ca2+]i. Thus, increase in [Ca2+]i produced by stimulation-induced Ca2+ entry would increase Sc-evoked cortical F-actin disassembly. Decrease in [Ca2+]i by either organelle sequestration or cell extrusion would favor Sc-evoked actin nucleation.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.001 | 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) | 0.000 | 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".