YAT1 (YAR035W; UniProt P80235) notes

• Carnitine O-acetyltransferase (EC 2.3.1.7), carnitine/choline acetyltransferase family [UniProt:P80235].
• Cloned as ethanol/acetate-inducible gene; protein in mitochondrial fraction; lacks cleavable presequence; deletion has no obvious phenotype; "likely to code for a minor mitochondrial outer carnitine acetyltransferase" PMID:8262985.
• UniProt instead lists mitochondrion inner membrane, intermembrane side (no cited evidence) - sub-mitochondrial location is unresolved.
• Isolated by complementation of a carnitine-dependent (cit2) mutant; all three CATs (CAT2, YAT1, YAT2) essential for growth on non-fermentable carbon in cit2 background PMID:11329169.
• Overexpression of single CATs does not cross-complement -> each has a specific metabolic role PMID:18427809.
• ISS "carnitine O-palmitoyltransferase activity" from rat CPT2 (P18886): yeast carnitine shuttle is described only for acetyl units; the only assayed activity of Yat1 is acetyltransferase PMID:8262985. Specificity from CPT2 similarity is not warranted.
• YAT1-YAT2 interaction found by Y2H (PMID:18719252) and AP-MS (PMID:37968396) - possibly a hetero-complex; untested.
• YeastPathways RCA cytosol is wrong for Yat1 (mitochondrial).