Protein kinase A is an enzyme that plays a crucial role in regulating various cellular processes by adding phosphate groups to proteins in response to cyclic AMP (cAMP) signaling. This enzyme is involved in a wide range of biological functions, including cell growth, metabolism, and gene expression. Dysregulation of protein kinase A activity has been implicated in various diseases, including cancer, diabetes, and neurological disorders. Research in this area focuses on understanding the structure, function, and regulation of protein kinase A, as well as developing targeted therapies and drugs that modulate its activity for therapeutic purposes.