What is the Difference Between Protein Kinase A and Protein Kinase C?

Protein Kinase A (PKA) and Protein Kinase C (PKC) are two subfamilies of protein kinases that belong to the AGC kinase group. They play important roles in several signal transduction cascades in living organisms. Here are the main differences between PKA and PKC:

1. Definition: PKA is a protein kinase enzyme that is cyclic AMP-dependent, while PKC is a protein kinase enzyme that is responsive to lipid signaling.
2. Function: PKA acts as the end effector for different hormones that work through a cAMP signaling pathway, while PKC responds to lipid signaling.
3. Substrate specificity: PKA primarily phosphorylates serine/threonine residues on target proteins, while PKC phosphorylates serine/threonine residues but has a preference for targeting serine residues.
4. Cellular localization: PKA is found in the cytoplasm of cells and 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.
5. 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.

In summary, PKA and PKC are both protein kinases involved in signal transduction, but they differ in their dependence on cAMP and lipid signaling, substrate specificity, cellular localization, and regulatory mechanisms.

Comparative Table: Protein Kinase A vs Protein Kinase C

Here is a table comparing the differences between Protein Kinase A (PKA) and Protein Kinase C (PKC):

Please note that the table above provides a summary of the main differences between PKA and PKC. For more detailed information, please refer to the sources provided.