Phosphorylation (continued)
   Limits duration of ligand activation
   (TFIIH and RARg and the proteosome, PKC and RARa and
    RXR dimerization)
Phosphorylation indirectly:
   Alters subcellular localization
   (PKA and RARa in Sertoli cells)
   Inhibits receptor function
   (RARa/g and ERKs)