THE INSULIN RECEPTOR IS A STABLE S-S LINKED DIMER
GROWTH HORMONE AND PROLACTIN
  RECEPTORS ARE LIGAND-INDUCED DIMERS
       IRS-1        
Stat 5A DEFICIENT MICE DO NOT LACTATE
TYROSINE KINASE
(JAK2)
Stat
IGF-1 USES A SIMILAR MECHANISM
-S-S-
-S-S-
S-S