Different Subcellular Localization and Phosphoinositides Binding of Insulin Receptor Substrate Protein Pleckstrin Homology Domains
| Autor: | Salvatore Sciacchitano, Giorgia Razzini, Alessandra Ingrosso, Diana L. Esposito, Marco Falasca, Anna Brancaccio |
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| Rok vydání: | 2000 |
| Předmět: |
Cytoplasm
Insulin Receptor Substrate Proteins Green Fluorescent Proteins Sequence Homology Biology Phosphatidylinositols Polymerase Chain Reaction Mice chemistry.chemical_compound Endocrinology Phosphatidylinositol Phosphates Insulin receptor substrate Animals Humans Insulin Phosphatidylinositol Molecular Biology Muscles Cell Membrane Intracellular Signaling Peptides and Proteins Tyrosine phosphorylation Blood Proteins General Medicine Fibroblasts Phosphoproteins IRS1 Cell biology Pleckstrin homology domain Luminescent Proteins Insulin receptor chemistry Mutagenesis Site-Directed biology.protein Phosphotyrosine-binding domain Subcellular Fractions |
| Zdroj: | Molecular endocrinology (Baltim. Md.) 14 (2000): 823–836. info:cnr-pdr/source/autori:Razzini G., Ingrosso A., Brancaccio A., Sciacchitano S., Esposito D.L., Falasca M./titolo:Different subcellular localization and phosphooinositides binding of insulin receptor substrate protein pleckstrin homology domains./doi:/rivista:Molecular endocrinology (Baltim. Md.)/anno:2000/pagina_da:823/pagina_a:836/intervallo_pagine:823–836/volume:14 |
| ISSN: | 1944-9917 0888-8809 |
| DOI: | 10.1210/mend.14.6.0486 |
| Popis: | Insulin evokes diverse biological effects through receptor-mediated tyrosine phosphorylation of the insulin receptor substrate (IRS) proteins. Here, we show that, in vitro, the IRS-1, -2 and -3 pleckstrin homology (PH) domains bind with different specificities to the 3-phosphorylated phosphoinositides. In fact, the IRS-1 PH domain binds preferentially to phosphatidylinositol 3,4,5-trisphosphate (PtdIns-3,4,5-P3), the IRS-2 PH domain to phosphatidylinositol 3,4-bisphosphate (PtdIns-3,4-P2), and the IRS-3 PH domain to phosphatidylinositol 3-phosphate. When expressed in NIH-IR fibroblasts and L6 myocytes, the IRS-1 and -2 PH domains tagged with green fluorescent protein (GFP) are localized exclusively in the cytoplasm. Stimulation with insulin causes a translocation of the GFP-IRS-1 and -2 PH domains to the plasma membrane within 3-5 min. This translocation is blocked by the phosphatidylinositol 3-kinase (PI 3-K) inhibitors, wortmannin and LY294002, suggesting that this event is PI 3-K dependent. Interestingly, platelet-derived growth factor (PDGF) did not induce translocation of the IRS-1 and -2 PH domains to the plasma membrane, indicating the existence of specificity for insulin. In contrast, the GFP-IRS-3 PH domain is constitutively localized to the plasma membrane. These results reveal a differential regulation of the IRS PH domains and a novel positive feedback loop in which PI 3-K functions as both an upstream regulator and a downstream effector of IRS-1 and -2 signaling. |
| Databáze: | OpenAIRE |
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