G Protein Coupled Receptors

G Protein Coupled Receptors

1. aka Seven-Pass Transmembrane Receptor Proteins

2. Largest family of receptor proteins in mammals

   • 30-50% drugs on market
   • Human genome has many orphan GPCRs

3. Types of G alpha proteins

   • Gs
     • stimulates adenylate cyclase
     • B Adrenergic Receptors
   • Gi
     • inhibits adenylate cyclase
     • M2 Muscarinic ACh Receptor
   • Gq
     • stimulates phospholipase C
     • M3 Muscarinic ACh Receptor
   • Gy12/13
     • altered conductance of G protein regulated K/ion channels

4. GPCR Pathways

   • Gi + M2 ACh receptor
     • Decreased adenylate cyclase
       • decreased cAMP
         • decreased protein kinase A
           • Decreased PKA mediated protein phosphorylation
   • Gs + B Adrenergic receptor/norepinephrine
     • Increased adenylate cyclase
       • increased cAMP
         • increased protein kinase A
           • Increased PKA mediated protein phosphorylation