cpt2 notes

2026-05-09 review notes

Reviewed GOA, UniProt Q5U3U3, and PANTHER family cache. The core role is mitochondrial inner-membrane carnitine O-palmitoyltransferase activity in long-chain fatty-acid beta-oxidation; generic acyltransferase and octanoyltransferase terms were treated as less specific/non-core relative to CPT2 activity.

Re-review 2026-09-29

• The previous review was fully templated: every row carried the same "consistent with the curated UniProt/GOA record" summary and the UniProt FUNCTION line as its only support, including the localization rows. All 12 rows rewritten with term-specific evidence.
• Found and cited the one zebrafish-specific study, PMID:39199302 (full text cached), which knocked cpt2 down with splice- and translation-blocking morpholinos: PMID:39199302 and, importantly for the localization rows, direct detection of the zebrafish protein PMID:39199302. Also cached PMID:20538056, the human CPT2 substrate-specificity study behind the ortholog EXP annotations.
• Resolved the PENDING row: GO:0005739 mitochondrion IEA (ARBA) -> KEEP_AS_NON_CORE, matching the IBA row for the same term; both now cite the zebrafish Western blot plus the UniProt inner-membrane line, with the reason stating that the inner membrane (matrix side) is the informative location.
• GO:0004095 carnitine O-palmitoyltransferase activity (IBA, IEA, ISS) all ACCEPT, now argued from the listed reaction and its stated physiological direction [file:DANRE/cpt2/cpt2-uniprot.txt "PhysiologicalDirection=right-to-left; Xref=Rhea:RHEA:12663"], i.e. the matrix-side conversion of acylcarnitine back to acyl-CoA, which is what the zebrafish paper describes.
• GO:0008458 carnitine O-octanoyltransferase activity (IEA, ISS) kept non-core, now with the measurement behind it PMID:20538056, plus the argument that medium-chain acyl-CoAs largely bypass the carnitine shuttle.
• GO:0015909 long-chain fatty acid transport kept non-core with an explicit participation argument: Cpt2 translocates nothing (that is the carnitine/acylcarnitine translocase) but catalyses the matrix-side step that makes the shuttle vectorial, and UniProt frames the reaction as "an essential step for the mitochondrial uptake of long-chain fatty acids".
• GO:0016746 acyltransferase activity MODIFY to GO:0004095 retained, with family and reaction evidence rather than boilerplate.
• No NEW terms proposed. The knockdown paper's neural, electrophysiological and behavioral phenotypes are downstream consequences of impaired fatty acid oxidation in a morphant; the gene product does no work in neurodevelopment, so they are recorded as a suggested question rather than annotations.
• Rewrote description as standalone biology (position in the carnitine shuttle, chain-length range, zebrafish knockdown phenotype); added suggested questions and experiments. Validation: zero errors, zero warnings.