What effects do PKA and phosphatase have on ACC (acetyl-CoA carboxylase)?

Acetyl-CoA carboxylase (ACC) plays a crucial role in fatty acid metabolism by catalyzing the conversion of acetyl-CoA to malonyl-CoA, which is a key step in fatty acid synthesis. The regulation of ACC is tightly controlled by various factors, including protein kinases and phosphatases.

Protein Kinase A (PKA) primarily operates through the phosphorylation of ACC, which results in its inactivation. When cellular energy levels are low, and there is an increase in the concentration of signaling molecules like glucagon or epinephrine, PKA is activated and phosphorylates ACC, thereby inhibiting its activity. This serves to decrease fatty acid synthesis when energy needs are high.

Conversely, phosphatases play a complementary role by dephosphorylating ACC. When ACC is dephosphorylated, its activity is restored, leading to increased production of malonyl-CoA, and promoting fatty acid synthesis. This dephosphorylation by phosphatases can be stimulated by conditions that indicate sufficient energy within the cell.

Overall, PKA inhibits ACC through phosphorylation, while phosphatases activate it by removing phosphate groups. This dynamic regulation ensures that fatty acid synthesis is promoted when energy