Insulin receptor substrate-1 (IRS-1) forms a ribonucleoprotein complex associated with polysomes

Insulin receptor substrates (IRSs) are known to play important roles in mediating intracellular insulin-like growth factors (IGFs)/insulin signaling. In this study, we identified components of messenger ribonucleoprotein (mRNP) as IRS-1-associated proteins. IRS-1 complex formation analysis revealed that IRS-1 is incorporated into the complexes of molecular mass more than 1000 kDa, which were disrupted by treatment with RNase. Furthermore, oligo(dT) beads precipitated IRS-1 from cell lysates, showing that the IRS-1 complexes contained messenger RNA. Taken together with the data that IRS-1 was fractionated into the polysome-containing high-density fractions, we concluded that IRS-1 forms the novel complexes with mRNPs. Structured summary of protein interactions: IRS1 physically interacts with PABPC1 by anti bait coimmunoprecipitation (View Interaction: 1,2) IRS1 physically interacts with PABPC1 by anti tag coimmunoprecipitation (View interaction) IRS1 physically interacts with PABPC1 by anti bait coimmunoprecipitation (View interaction) IRS1 physically interacts with EIF4F and PABPC1 by anti bait coimmunoprecipitation (View interaction) (C) 2013 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.