title: Suppressor of cytokine signaling (SOCS)-3 protein interacts with the insulin-like growth factor-I receptor.
abstract: SOCS proteins are a class of proteins that are negative regulators of cytokine receptor signaling via the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. In a yeast two-hybrid screen of a human fetal brain library, we have previously identified SOCS-2 as a binding partner of the activated IGF-I receptor (IGFIR). To test whether or not SOCS-3 also binds to the IGFIR, we cloned human SOCS-3 by reverse transcription-polymerase chain reaction from human skeletal muscle mRNA. SOCS-3 mRNA was expressed in many human fetal and adult tissues and in some human cancer cell lines (Hela, A549 pulmonary adenocarcinoma and G361 human melanoma). We found that human SOCS-3 protein interacts directly with the cytoplasmic domains of the activated IGFIR and the insulin receptor (IR) in the yeast two-hybrid assay. In GST-SOCS-3 pull-down experiments using IGFIR from mammalian cells and in immunoprecipitation experiments in which IGFIR and FLAG-SOCS-3 were transiently expressed in human embryonic kidney 293 cells, we found that SOCS-3 interacts constitutively with IGFIR in vitro and in intact cells. Unlike SOCS-2, hSOCS-3 was phosphorylated on tyrosines in response to IGF-I addition to 293 cells. We conclude that SOCS-3 binds to the IGFIR and may be a direct substrate for the receptor tyrosine kinase.
authors.affiliation: Metabolism Branch, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: B R
authors.initials: BR
authors.lastname: Dey
authors.forename: R W
authors.initials: RW
authors.lastname: Furlanetto
authors.forename: P
authors.initials: P
authors.lastname: Nissley
mesh_terms: D000818:Animals; D015152:Blotting, Northern; D001921:Brain / Q000196:embryology / Q000378:metabolism; D002460:Cell Line; D003001:Cloning, Molecular; D003593:Cytoplasm / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D015723:Gene Library; D005982:Glutathione Transferase / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D019169:Jurkat Cells; D008024:Ligands; D018482:Muscle, Skeletal / Q000378:metabolism; D010766:Phosphorylation; D010957:Plasmids / Q000378:metabolism; D011233:Precipitin Tests; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D011506:Proteins / Q000235:genetics* / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D017526:Receptor, IGF Type 1 / Q000378:metabolism*; D011972:Receptor, Insulin / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D012097:Repressor Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D014018:Tissue Distribution; D014157:Transcription Factors; D014407:Tumor Cells, Cultured; D020798:Two-Hybrid System Techniques; D014443:Tyrosine / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D008024:Ligands; D011506:Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D012097:Repressor Proteins; C106644:SOCS3 protein, human; D000071223:Suppressor of Cytokine Signaling 3 Protein; D050826:Suppressor of Cytokine Signaling Proteins; D014157:Transcription Factors; D014443:Tyrosine; D007334:Insulin-Like Growth Factor I; D005982:Glutathione Transferase; D017526:Receptor, IGF Type 1; D011972:Receptor, Insulin