Janus kinases (JAKs) and signal transducers and activators of transcription (STATs) in hematopoietic cells

Hematopoietic cell growth and differentiation are controlled by a number of cytokines. Ligand stimulation induces rapid phosphorylation of the tyrosin e residues of the cytokine receptor and a variety of cellular molecules. Am ong them, Janus kinases (JAKs) and signal transducers and activators of tra nscription (STATs) have recently been found to play a unique role in cytoki ne receptor-mediated intracellular signaling and hematopoietic cell develop ment. Abnormal signaling of the JAK-STAT pathway results in hematopoietic d isorders, including severe combined immunodeficiency and leukemia. Int J He matol. 2000;71:309-319. (C) 2000 The Japanese Society of Hematology.