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Type: Artigo de periódico
Title: Growth Hormone Stimulates The Tyrosine Kinase Activity Of Jak2 And Induces Tyrosine Phosphorylation Of Insulin Receptor Substrates And Shc In Rat Tissues.
Author: Thirone, A C
Carvalho, C R
Saad, M J
Abstract: GH stimulates the tyrosine phosphorylation of various cellular polypeptides, including the GH receptor itself, in an early part of the intracellular response. Some of these phosphorylations are catalyzed by a GH receptor-associated kinase identified as JAK2, a member of the Janus family of tyrosine kinases. In cultured cells, GH stimulates the tyrosine phosphorylation of insulin receptor substrate-1 (IRS-1), IRS-2, and Shc. This study investigated whether GH could cause the tyrosine phosphorylation of IRSs and Shc proteins in fasted rat tissues in vivo. GH was administered to fasted Wistar rats via a portal vein, and extracts of different tissues were immunoprecipitated with specific antibodies. GH increased the tyrosine phosphorylation of IRS-1, IRS-2, JAK2, and Shc proteins in the liver, heart, kidney, muscle, and adipose tissue of rats. The roles of these substrates as signaling molecules for GH were further demonstrated by the finding that GH stimulated the association of IRS-1/2 with phosphatidylinositol 3-kinase, Grb2, and phosphotyrosine phosphatase and of Shc with Grb2. The correlation between JAK2 tyrosyl phosphorylation and IRS-1 tyrosyl phosphorylation in response to GH together with the results of the in vitro tyrosine kinase assay are consistent with the hypothesis that JAK2 may mediate GH-induced phosphorylation of IRS-1.
Subject: Adaptor Proteins, Signal Transducing
Adaptor Proteins, Vesicular Transport
Grb2 Adaptor Protein
Growth Hormone
Insulin Receptor Substrate Proteins
Intracellular Signaling Peptides And Proteins
Janus Kinase 2
Phosphatidylinositol 3-kinases
Protein Tyrosine Phosphatase, Non-receptor Type 11
Protein Tyrosine Phosphatase, Non-receptor Type 6
Protein Tyrosine Phosphatases
Protein-tyrosine Kinases
Proto-oncogene Proteins
Rats, Wistar
Receptor, Insulin
Sh2 Domain-containing Protein Tyrosine Phosphatases
Shc Signaling Adaptor Proteins
Src Homology Domains
Citation: Endocrinology. v. 140, n. 1, p. 55-62, 1999-Jan.
Rights: fechado
Identifier DOI: 10.1210/endo.140.1.6417
Date Issue: 1999
Appears in Collections:Unicamp - Artigos e Outros Documentos

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