title: Mapping of a cytoplasmic domain of the human growth hormone receptor that regulates rates of inactivation of Jak2 and Stat proteins.
abstract: It has been previously demonstrated that growth hormone (GH)-stimulated tyrosine phosphorylation of Jak2 and Stat5a and Stat5b occurs in FDP-C1 cells expressing either the entire GH receptor or truncations of the cytoplasmic domain expressing only the membrane-proximal 80 amino acids. However, other receptor domains that might modulate rates of GH activation and inactivation of this cascade have not been examined. Here we have defined a region in the human GH receptor between amino acids 520 and 540 in the cytoplasmic domain that is required for attenuation of GH-activated Jak/Stat signaling. Immunoprecipitations with antibodies to Jak2 indicate that the protein tyrosine phosphatase SHP-1 is associated with this kinase in cells exposed to GH. To address the possibility that SHP-1 could function as a negative regulator of GH signaling, liver extracts from motheaten mice deficient in SHP-1 or unaffected littermates were analyzed for activation of Stats and Jak2. Extracts from motheaten mice displayed prolonged activation of the Stat proteins as measured by their ability to interact with DNA and prolonged tyrosine phosphorylation of Jak2. These results delineate a novel domain in the GH receptor that regulates the inactivation of the Jak/Stat pathway and appears to be modulated by SHP-1.
authors.affiliation: Division of Cytokine Biology, Center for Biologics Evaluation and Research, Bethesda, Maryland 20892, USA.
authors.forename: R H
authors.initials: RH
authors.lastname: Hackett
authors.forename: Y D
authors.initials: YD
authors.lastname: Wang
authors.forename: S
authors.initials: S
authors.lastname: Sweitzer
authors.forename: G
authors.initials: G
authors.lastname: Feldman
authors.forename: W I
authors.initials: WI
authors.lastname: Wood
authors.forename: A C
authors.initials: AC
authors.lastname: Larner
mesh_terms: D000818:Animals; D004268:DNA-Binding Proteins / Q000378:metabolism*; D013006:Growth Hormone / Q000494:pharmacology*; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins; D053614:Janus Kinase 2; D008099:Liver / Q000378:metabolism; D051379:Mice; D008817:Mice, Mutant Strains; D008894:Milk Proteins; D010766:Phosphorylation; D011485:Protein Binding; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D011986:Receptors, Somatotropin / Q000235:genetics / Q000378:metabolism*; D050799:STAT5 Transcription Factor; D017384:Sequence Deletion; D015398:Signal Transduction; D013347:Subcellular Fractions / Q000378:metabolism; D015534:Trans-Activators / Q000378:metabolism*; D025521:Tumor Suppressor Proteins
chemical_list: D004268:DNA-Binding Proteins; D047908:Intracellular Signaling Peptides and Proteins; D008894:Milk Proteins; D011518:Proto-Oncogene Proteins; D011986:Receptors, Somatotropin; D050799:STAT5 Transcription Factor; C494092:STAT5A protein, human; C494095:STAT5B protein, human; C494093:Stat5a protein, mouse; C494096:Stat5b protein, mouse; D015534:Trans-Activators; D025521:Tumor Suppressor Proteins; D013006:Growth Hormone; D011505:Protein-Tyrosine Kinases; C507924:JAK2 protein, human; C507926:Jak2 protein, mouse; D053614:Janus Kinase 2; C516724:PTPN11 protein, human; C509249:PTPN6 protein, human; D054592:Protein Tyrosine Phosphatase, Non-Receptor Type 11; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; D017027:Protein Tyrosine Phosphatases; C516725:Ptpn11 protein, mouse; C509248:Ptpn6 protein, mouse