The role of STAT5 in lymphocyte development and transformation

STAT5 plays a crucial role in B and T lymphocyte development. However, whether STAT5 primarily plays a role as a permissive factor, involved in lymphocyte survival, or an instructive factor, involved in lymphocyte differentiation, has been unclear. In addition, while STAT5 has been suggested to act as a transcriptional repressor, the mechanism by which it represses transcription was undefined. Recent reports have begun to shed new light on these roles for STAT5 in lymphocyte development, transcriptional repression, and leukemic transformation.

► STAT5 plays a permissive role as a pro-survival factor in lymphocyte development.
► STAT5 regulates lymphocyte differentiation.
► STAT5 functions as both an activator and a repressor of transcription.
► STAT5 plays an important role in initiating acute lymphoblastic leukemia.