Screening for serine/threonine kinases phosphorylating Stat5

Background Stat transcription factors are highly conserved key regulators of cellular processes such as proliferation, differentiation, growth and apoptosis. Stats have been frequently found to be deregulated in cancer. One example is the constitutive activation of Stat5 in chronic myelogenous leukaemia (CML). The disease is caused by a chromosomal translocation resulting in the expression of the Bcr/ Abl fusion kinase. The transcription factor Stat5 is required for Bcr/Abl-induced leukaemic initiation and disease progression. Furthermore, serine phosphorylation of a constitutive active form of Stat5 is crucial for haematopoietic transformation. These findings put Stat5 into the spotlight of new therapeutic tactics. Here, we screen for kinases phosphorylating Stat5 by employing a cell viability-based screening approach.