Protein Kinase C

Protein Kinase C

1. Regulated by two mechanisms

   • PHOSPHORYLATION
     • Regulates the active site and subcellular localization of the enzyme.
   • SECOND MESSENGERS
     • Promote protein kinase C's membrane association and resulting pseudosubstrate exposure.

2. transduces the myriad of signals promoting lipid hydrolysis.

3. Structure

   • Comprised of an N-terminal regulatory region and a C-terminal catalytic region
     • 11 protein kinase C isozymes have been identified and classified into three groups based on their structure and cofactor regulation

4. Function

   • Enzymology
     • Protein kinase C typically phosphorylates serine or threonine residues in basic sequences.
       • In addition to catalyzing phosphorylation reactions, protein kinase C has ATPase and phosphatase activity.

5. Biological Function

   • in receptor desensitization, in modulating membrane structure events, in regulating transcription.
   • in mediating immune responses, in regulating cell growth, and in learning and memory.

6. Pseudosubstrate Regulation

   • Diacylglycerol and Phorbol Esters
     • Phosphatidylserine
       • Calcium Ions
         • Substrates