Protein kinase A (PKA)

Protein kinase A (PKA) is an enzyme that plays a key role in cell signaling by transferring phosphate groups to specific proteins, a process called phosphorylation. This modification can change a protein's activity, such as turning it on or off, affecting processes like metabolism, gene expression, and cell growth. PKA is activated by cyclic AMP (cAMP), a signaling molecule that relays signals like hormonal messages (e.g., adrenaline). Once activated, PKA distributes these signals within the cell, helping coordinate appropriate responses to external stimuli and maintain cellular function.