[Immuno-hematopoietic cytokine receptor family--its structure and function]

Receptors for immuno-hematopoietic cytokines are multi-chain complexes of membrane proteins. Molecular cloning of these cytokine receptor genes revealed the existence of a here-to-fore unidentified receptor superfamily. They are primarily characterized by a shared extracellular structure that may be involved in the formation of multi-chain receptor complex. Inspite of the lack of any catalytic function, several members of the superfamily are known to act as the transmembrane transducers of cytokine signals. Such molecules may interact physiologically/functionally with multiple intracellular catalytic molecules to generate signals. In this regard, potential involvement of protein tyrosine kinase and protein serine/threonine kinase in the post-receptor signalling has been described. Dysregulated activation of the cytokine receptor gives rise to transformation of immuno-hematopoietic cells.