Growth‐hormone‐receptor and cytokine‐receptor‐family signaling

Structure of growth‐hormone receptor and the class I type of cytokine receptors : common structural features; cytokine‐receptor isoforms; oligomerization of receptor components initiates cytokine signalling. Role of the Jak kinases in mediating specific functions of growth‐hormone receptor and cytokine receptors. Role of signal transducer and activator of transcription (Stat) proteins in growth hormone and cytokine functions. Other pathways activated by cytokine receptors : the mitogen‐activated protein kinase pathway; insulin‐receptor substrates 1 and 2 and phosphatidylinositol‐3‐kinase pathways; the Src pathways and other tyrosine kinase pathways; the phospholipase C/protein kinase C/Ca2+ pathways. Regulation of growth‐hormone receptor and cytokine receptor signaling : binding sites, internalization and ubiquitination; phosphatases and Janus kinase/Stat inhibitors. Conclusions and future prospects.