CPT1C

CPT1C, or carnitine palmitoyltransferase 1C, is a member of the carnitine palmitoyltransferase 1 family. The CPT1 family comprises enzymes that participate in the transport of long-chain fatty acids into mitochondria for beta-oxidation, with CPT1A and CPT1B playing prominent roles in liver and muscle, respectively. CPT1C is encoded by the CPT1C gene in humans.

CPT1C is predominantly expressed in the brain, with notable levels in regions involved in energy balance and neuroendocrine regulation, such as the hypothalamus. Unlike its paralogs, CPT1A and CPT1B, CPT1C localizes mainly to the endoplasmic reticulum rather than the mitochondrial outer membrane. Its precise catalytic activity remains uncertain, and it is generally considered to have little or no conventional fatty acid transferase activity.

Functionally, CPT1C is thought to act more as a lipid sensor or regulatory protein than as an enzyme driving fatty acid oxidation. In neurons, it is implicated in signaling pathways that respond to nutrient status and energy availability, potentially influencing appetite regulation, energy homeostasis, and ER lipid metabolism. Some evidence also links CPT1C to endoplasmic reticulum stress signaling and the coordination of neuronal metabolic responses.

Clinical and physiological relevance is an active area of research. Genetic variants in CPT1C have been studied for associations with metabolic traits, and animal models suggest CPT1C can influence brain energy regulation, though the exact mechanisms are not fully understood. Overall, CPT1C remains less well characterized than CPT1A and CPT1B, with ongoing research into its enzymatic capacity and roles in health and disease.