ACC2 is most likely to be found in which cellular compartment?

• A. The cytosol
• B. The lysosome
• C. The mitochondria
• D. The cell membrane

Answer: (C)

ACC2, or Acetyl-CoA Carboxylase 2, is primarily involved in fatty acid metabolism and is specifically located in the mitochondria of cells. This enzyme plays a crucial role in converting acetyl-CoA to malonyl-CoA, which is a pivotal step in fatty acid synthesis and regulation.

The mitochondrial localization is important because the production of malonyl-CoA directly influences the fatty acid synthesis pathway, as well as the transport of fatty acids into the mitochondria for oxidation. Additionally, the regulation of ACC2 occurs in the context of energy metabolism, where its activity is affected by the energy state of the cell, meaning its presence in the mitochondria allows it to respond quickly to changing metabolic needs.

While the cytosol is a location for many metabolic processes, including some forms of fatty acid synthesis, ACC2 is particularly noted for its mitochondrial activity. The lysosome is involved in degradation processes, and the cell membrane is primarily associated with structural and signaling functions, making these locations less relevant for ACC2's activity. Thus, the principal presence of ACC2 in the mitochondria emphasizes its key role in linking metabolic pathways related to fatty acid metabolism within that cellular compartment.