• The covalent attachment of ubiquitin inactivates D2 by disrupting dimerization and targets it to degradation in the proteosome.
• Deubiquitination removing ubiquitin from D2 restores its activity and prevents proteosomal degradation.
• The Hedgehog cascade acts to increase D2 ubiquitination through WSB1 activity, decreasing D2 activity.
D-propranolol inhibits thyroxine deiodinase, thereby blocking the conversion of T4 to T3, providing some though minimal therapeutic effect.