Interaction of growth hormone-activated STATs with SH2-containing phosphotyrosine phosphatase SHP-1 and nuclear JAK2 tyrosine kinase.
Growth hormone (GH) rapidly stimulates tyrosine phosphorylation followed by serine/threonine phosphorylation of multiple cytoplasmic STAT transcription factors, including one, STAT5b, that is uniquely responsive to the temporal pattern of plasma GH stimulation in rat liver and is proposed to play a central role in the activation of male-expressed liver genes ... by GH pulses in vivo (Waxman, D. J., Ram, P. A., Park, S. H., and Choi, H. K. (1995) J. Biol. Chem. 270, 13262-13270). We now show that JAK2, the GH receptor-associated tyrosine kinase, is present both in the cytosol and in the nucleus in cultured liver cells and in rat liver in vivo and that GH-activated STAT3 but not STAT5b becomes associated with nuclear JAK2. GH is also shown to activate by 3-4-fold SHP-1, a phosphotyrosine phosphatase that contains two src homology 2 (SH2) domains. GH also induces nuclear translocation and binding of SHP-1 to tyrosine-phosphorylated STAT5b, suggesting that this GH-activated phosphatase may play a role in dephosphorylation leading to deactivation of nuclear STAT5b following the termination of a plasma GH pulse in male rat liver in vivo. No such association of SHP-1 with GH-activated STAT3 was detected, a finding that could help explain the marked desensitization of STAT3, but not STAT5b, to subsequent GH pulses following an initial GH activation event.
Mesh Terms:
Animals, Cell Nucleus, DNA-Binding Proteins, Enzyme Activation, Growth Hormone, Humans, Intracellular Signaling Peptides and Proteins, Janus Kinase 2, Liver, Male, Milk Proteins, Phosphorylation, Protein Tyrosine Phosphatase, Non-Receptor Type 11, Protein Tyrosine Phosphatase, Non-Receptor Type 6, Protein Tyrosine Phosphatases, Protein-Tyrosine Kinases, Proto-Oncogene Proteins, Pulsatile Flow, Rats, Rats, Inbred F344, SH2 Domain-Containing Protein Tyrosine Phosphatases, STAT3 Transcription Factor, STAT5 Transcription Factor, Signal Transduction, Subcellular Fractions, Trans-Activators, src Homology Domains
Animals, Cell Nucleus, DNA-Binding Proteins, Enzyme Activation, Growth Hormone, Humans, Intracellular Signaling Peptides and Proteins, Janus Kinase 2, Liver, Male, Milk Proteins, Phosphorylation, Protein Tyrosine Phosphatase, Non-Receptor Type 11, Protein Tyrosine Phosphatase, Non-Receptor Type 6, Protein Tyrosine Phosphatases, Protein-Tyrosine Kinases, Proto-Oncogene Proteins, Pulsatile Flow, Rats, Rats, Inbred F344, SH2 Domain-Containing Protein Tyrosine Phosphatases, STAT3 Transcription Factor, STAT5 Transcription Factor, Signal Transduction, Subcellular Fractions, Trans-Activators, src Homology Domains
J. Biol. Chem.
Date: Jul. 11, 1997
PubMed ID: 9211920
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