P42229, P51692

Stat5 also known as stat5a/b, stat5a/stat5b is a member of the STAT family of transcription factors. Stat5 proteins play a pivotal role in mediating cellular responses to cytokines and growth factors by undergoing phosphorylation through receptor tyrosine kinases or G protein-coupled receptors. Upon activation, stat5a and stat5b form homo- or heterodimers that translocate to the nucleus to initiate transcription of genes involved in cell proliferation, differentiation, and apoptosis, particularly within lymphohematopoietic cells. This signaling is crucial for processes like T-cell receptor signaling, mammary gland development, and regulation of liver gene expression related to sexual dimorphism. Aberrant stat5 activity is associated with various diseases, including acute promyelocytic leukemia, where stat5b can fuse with the retinoic acid receptor alpha gene.