Growth hormone signalling mechanisms: involvement of the tyrosine kinase JAK2.

Demonstration that the tyrosine kinase JAK2 is activated in response to growth hormone (GH) has established tyrosyl phosphorylation as a signalling mechanism for GH. In addition a number of signalling molecules have recently been identified that interact with the GH receptor/JAK2 complex and require JAK2 for activation. These pathways regulate cellular functions including gene transcription, metabolite transport, and metabolism and contribute to the ability of GH to control body growth and metabolism.