A. Sotiropoulos et al., THE MEMBRANE PROXIMAL REGION OF THE CYTOPLASMIC DOMAIN OF THE GROWTH-HORMONE RECEPTOR IS INVOLVED IN THE ACTIVATION OF STAT-3, FEBS letters, 369(2-3), 1995, pp. 169-172
Growth hormone receptor (GHR) signaling involves activation of the Jan
us Kinases (Jak) and of Stat proteins (signal transducers and activato
rs of transcription). Growth hormone (GH) induces transcriptional acti
vation of c-fos gene and the c-sis inducible element (SLE) of its prom
oter was shown to bind the Stat proteins. Using cells co-transfected,v
ith GHR and Stat 3 expression vectors, we directly demonstrate that GH
induces tyrosine phosphorylation of Stat 3 and its binding to the SIE
probe. We showed, using mutant forms of GHR, that only the cytoplasmi
c membrane proximal domain of the receptor, including a conserved prol
ine rich region (box 1), is required for this effect.