Stat5a and Stat5b proteins have essential and nonessential, or redundant, roles in cytokine responses

Cell. 1998 May 29;93(5):841-50. doi: 10.1016/s0092-8674(00)81444-0.


A variety of cytokines mediate the activation of Janus protein tyrosine kinases (Jaks). The Jaks then phosphorylate cellular substrates, including members of the signal transducers and activators of transcription (Stat) family of transcription factors. Among the Stats, the two highly related proteins, Stat5a and Stat5b, are activated by a variety of cytokines. To assess the role of the Stat5 proteins, mutant mice were derived that have the genes deleted individually or together. The phenotypes of the mice demonstrate an essential, and often redundant, role for the two Stat5 proteins in a spectrum of physiological responses associated with growth hormone and prolactin. Conversely, the responses to a variety of cytokines that activate the Stat5 proteins, including erythropoietin, are largely unaffected.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Body Constitution
  • Cytokines / pharmacology*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism*
  • Erythropoietin / pharmacology
  • Female
  • Gene Deletion
  • Growth Hormone / metabolism
  • Hematopoiesis / genetics
  • Infertility, Female / genetics
  • Mammary Glands, Animal / growth & development
  • Mice
  • Mice, Mutant Strains
  • Milk Proteins*
  • Ovary / growth & development
  • Prolactin / pharmacology*
  • STAT5 Transcription Factor
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*


  • Cytokines
  • DNA-Binding Proteins
  • Milk Proteins
  • STAT5 Transcription Factor
  • Stat5a protein, mouse
  • Stat5b protein, mouse
  • Trans-Activators
  • Erythropoietin
  • Prolactin
  • Growth Hormone