What are the differences between protein kinase A and protein kinase C?

Basis of differentiation

Protein kinase A

Protein kinase C

Definition

Protein kinase A is a protein kinase enzyme that is cyclic AMP dependent

Protein kinase C is a specific type of protein kinase enzyme that is responsive to lipid signaling

Function

PKA is the end effector for different hormones that work through a cAMP signaling pathway

PKC responds to lipid signaling

Substrate specificity 

PKA primarily phosphorylates serine/threonine residues on target proteins 

PKC phosphorylates serine/threonine residues but has a preference for targeting serine residues within specific circumstances (usually preceded by hydrophobic or acidic residues) 

Cellular localization

PKA is found in the cytoplasm of cells. It is localized to specific areas of the cell by interacting with A-kinase anchoring proteins

PKC can be found in different areas of the cell including the cytoplasm, plasma membrane, and other organelles 

Mechanism

PKA is regulated by cAMP levels, which determine its activation state

PKC is regulated by multiple complex mechanisms including DAG, Ca2+, protein-protein interactions, and phospholipids