Molecular Endocrinology and Signal Transduction

Molecular Endocrinology and Signal Transduction

X-ray crystallographic studies and functional studies of the extracellular domain of the hGH receptor suggest that two receptor molecules form a dimer with a single growth hormone molecule by sequentially binding to Site 1 on Helix 4 of hGH and then to Site 2 onHelix 1 (Fig. 4) (Wells et al., 1993). Signal transduction may occur by activation/phosphorylation of JAK-2 tyrosine kinase followed by activation/phosphoryla-tion of multiple signaling cascades (Herrington and Carter-Su, 2001; Piwien-Pilipuk et al., 2002).