What is the Origin of Protein Kinase A?

The term is derived from biochemistry and molecular biology, combining "protein kinase," an enzyme that modifies other proteins by adding phosphate groups, with "A," denoting its dependence on cyclic AMP. Its discovery was central to understanding intracellular signal transduction.

What is the Mechanism of Protein Kinase A?

PKA is typically maintained in an inactive tetrameric state. Upon binding of the second messenger cAMP, the regulatory subunits dissociate from the catalytic subunits, allowing the active catalytic subunits to phosphorylate target proteins. This phosphorylation event acts as a molecular switch, altering the function of enzymes, ion channels, and transcription factors, which is how hormones like glucagon and adrenaline exert their diverse physiological effects.

Protein Kinase A

Meaning

A crucial enzyme, also known as cyclic AMP-dependent protein kinase (PKA), that acts as a central mediator in numerous cellular signaling pathways, primarily those activated by hormones and neurotransmitters that utilize cyclic AMP (cAMP) as a second messenger. PKA’s function is to phosphorylate specific proteins, thereby regulating gene expression, metabolic processes, and cellular responses to external stimuli. It is a fundamental component of the endocrine signaling cascade.