After dimerization STAT dimers release from the receptor complex and migrate to the nucleus for DNA binding. STAT5s/STAT1alpha heterodimeric complexes specifically recognize beta-casein promoter region (PIE) (Brizzi et al. 1999). c-Kit dependent JAK/STAT activation is associated with the growth and differentiation of fetal liver haematopoietic progenitor cells (Rönnstrand 2004, Reber et al. 2006).