Evolution of the regulatory control of vertebrate striated muscle: the roles of troponin I and myosin binding protein-C
Why this work is in the frame
A frame that forgets how it found something cannot be audited. These are the routes that admitted this work.
Bibliographic record
Abstract
Troponin I (TnI) and myosin binding protein-C (MyBP-C) are key regulatory proteins of contractile function in vertebrate muscle. TnI modulates the Ca(2+) activation signal, while MyBP-C regulates cross-bridge cycling kinetics. In vertebrates, each protein is distributed as tissue-specific paralogs in fast skeletal (fs), slow skeletal (ss), and cardiac (c) muscles. The purpose of this study is to characterize how TnI and MyBP-C have changed during the evolution of vertebrate striated muscle and how tissue-specific paralogs have adapted to different physiological conditions. To accomplish this we have completed phylogenetic analyses using the amino acid sequences of all known TnI and MyBP-C isoforms. This includes 99 TnI sequences (fs, ss, and c) from 51 different species and 62 MyBP-C sequences from 26 species, with representatives from each vertebrate group. Results indicate that the role of protein kinase A (PKA) and protein kinase C (PKC) in regulating contractile function has changed during the evolution of vertebrate striated muscle. This is reflected in an increased number of phosphorylatable sites in cTnI and cMyBP-C in endothermic vertebrates and the loss of two PKC sites in fsTnI in a common ancestor of mammals, birds, and reptiles. In addition, we find that His(132), Val(134), and Asn(141) in human ssTnI, previously identified as enabling contractile function during cellular acidosis, are present in all vertebrate cTnI isoforms except those from monotremes, marsupials, and eutherian mammals. This suggests that the replacement of these residues with alternative residues coincides with the evolution of endothermy in the mammalian lineage.
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.
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 | 0.001 |
| 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 it