IRS-1 Tyrosine Phosphorylation Reflects Insulin-Induced Metabolic and Mitogenic Responses in 3T3-L1 Pre-Adipocytes

Autor: J. Dorrestijn, G. van der Zon, J. A. Maassen, Darryl Telting
Rok vydání: 2001
Předmět:
Time Factors
Insulin Receptor Substrate Proteins
Physiology
Recombinant Fusion Proteins
Blotting
Western

Protein Serine-Threonine Kinases
Mice
Phosphatidylinositol 3-Kinases
chemistry.chemical_compound
Epidermal growth factor
Proto-Oncogene Proteins
Physiology (medical)
Insulin receptor substrate
Adipocytes
Animals
Insulin
Phosphorylation
Glycogen synthase
Protein kinase B
Mitogen-Activated Protein Kinase 1
Mitogen-Activated Protein Kinase 3
Dose-Response Relationship
Drug

Epidermal Growth Factor
biology
Intracellular Signaling Peptides and Proteins
Tyrosine phosphorylation
3T3 Cells
DNA
General Medicine
Phosphoproteins
Precipitin Tests
Receptor
Insulin

Protein Structure
Tertiary

Cell biology
Insulin receptor
Biochemistry
chemistry
biology.protein
Tyrosine
Mitogen-Activated Protein Kinases
Proto-Oncogene Proteins c-akt
Glycogen
Thymidine
Zdroj: Archives of Physiology and Biochemistry. 109:52-62
ISSN: 1744-4160
1381-3455
DOI: 10.1076/apab.109.1.52.4278
Popis: We determined the involvement of Tyr-1158 within the regulatory loop of the insulin receptor (IR) in the generation of insulin-specific responses in situ. For this purpose chimeric receptors with an epidermal growth factor (EGF) receptor extracellular domain and an IR cytoplasmic domain (EIR) were constructed, which allow activation of the cytoplasmic IR domain without activation of endogenous wt-IRs. Tyr-1158 of the chimera EIR was exchanged for Phe, creating a mutant chimeric receptor (EIR-Y1158F). Chimeric receptors were expressed in 3T3-L1 pre-adipocytes, which do not show insulin-specific responses upon EGF stimulation. We found that pre-adipocytes expressing EIR-Y1158F were impaired in their ability to stimulate glycogen synthesis and DNA synthesis upon maximal stimulation with EGF. EIR-Y1158F was impaired in its ability to phosphorylate insulin receptor substrate (IRS)-1 and induce downstream signals of IRS-1 phosphorylation, such as the association of IRS-1 with phosphatidyl-inositol-3'-kinase and the activation of protein kinase B (Akt). In contrast with the phosphorylation of IRS-1, the phosphorylation of IRS-2 and extracellular regulated protein kinase-1/-2 was normal in EIR-Y1158F expressing cells. These observations suggest that the level of IRS-1 phosphorylation rather than the level of IRS-2 phosphorylation mediates insulin-induced glycogen synthesis and DNA synthesis in 3T3-L1 pre-adipocytes.
Databáze: OpenAIRE