Functionally Distinct Isoforms of STAT5 Are Generated by Protein Processing

Immunity. 1997 Jun;6(6):691-701. doi: 10.1016/s1074-7613(00)80445-8.


The interleukin-3 family of cytokines, which play an important role in the development of myeloid lineages, transduce signals through the JAK-STAT pathway. Previous studies demonstrate that this process entails the activation of four distinct isoforms of STAT5, where two shorter isoforms are activated in a distinct population of cells. We now demonstrate that the shorter isoforms represent carboxy-terminal truncations. Moreover, these truncations are not generated by RNA processing, but by a specific proteolytic activity. Consistent with the notion that truncated STAT5 isoforms transduce distinct signals, they fail to promote the activation of several known interleukin-3 target genes. These studies suggest that the activity of a specific protease may play a critical role in defining the biological responses transduced by STAT5.

Publication types

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

MeSH terms

  • Cells, Cultured
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / metabolism
  • Gene Expression Regulation
  • Humans
  • Interleukin-3 / genetics
  • Interleukin-3 / physiology
  • Milk Proteins*
  • Molecular Weight
  • Protein Processing, Post-Translational
  • RNA Processing, Post-Transcriptional
  • RNA, Messenger / genetics
  • STAT5 Transcription Factor
  • Signal Transduction
  • Structure-Activity Relationship
  • Trans-Activators / chemistry*
  • Trans-Activators / metabolism


  • DNA-Binding Proteins
  • Interleukin-3
  • Milk Proteins
  • RNA, Messenger
  • STAT5 Transcription Factor
  • Trans-Activators