Expression and regulation of carnitine palmitoyltransferase-Ialpha and -Ibeta genes.
Two genes control expression of mitochondrial carnitine palmitoyltransferase-I (CPT-I), the enzyme that catalyzes the primary rate-controlling step in fatty acid oxidation. Two CPT-I isoforms have been found--a "liver" isoform (CPT-Ialpha) expressed in most tissues, but not in skeletal muscles, and a "muscle" isoform (CPT-Ibeta) expressed in muscles and adipocytes. Liver CPT-Ialpha increases dramatically at birth, but heart CPT-Ialpha is abundant in the fetus and diminishes at birth. Insulin, thyroid hormone, and fatty acids regulate expression of CPT-Ialpha in liver, whereas electrical stimulation increases CPT-Ibeta and decreases CPT-Ialpha in cardiac myocytes. Both genes are TATA-less and contain Sp1 transcription factor binding sites upstream of the start site of transcription. Multiple transcripts of both CPT-Ialpha and CPT-Ibeta exist, some of which may have roles in regulating fatty acid oxidation.
Department of Pharmacology, College of Medicine, The University of Tennessee, Memphis 38163, USA. gcook@utmem1.utmem.edu
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D000818:Animals; D002334:Carnitine O-Palmitoyltransferase / Q000235:genetics*; D005227:Fatty Acids / Q000378:metabolism*; D015971:Gene Expression Regulation, Enzymologic; D006801:Humans; D007527:Isoenzymes / Q000235:genetics; D008928:Mitochondria / Q000201:enzymology*; D008929:Mitochondria, Heart / Q000201:enzymology; D008930:Mitochondria, Liver / Q000201:enzymology; D010084:Oxidation-Reduction
D005227:Fatty Acids; D007527:Isoenzymes; D002334:Carnitine O-Palmitoyltransferase