Distinct signalling properties of insulin receptor substrate (IRS)-1 and IRS-2 in mediating insulin/IGF-1 action

• Published in: Cellular signalling 2018-07, Vol.47, p.1-15
• Main Authors: Rabiee, Atefeh, Krüger, Marcus, Ardenkjær-Larsen, Jacob, Kahn, C. Ronald, Emanuelli, Brice
• Format: Article
• Language: English
• Subjects: Adipose Tissue, Brown - cytology; Adipose Tissue, Brown - metabolism; Animals; Chromatography, High Pressure Liquid; Insulin - pharmacology; Insulin receptor substrate; Insulin Receptor Substrate Proteins - deficiency; Insulin Receptor Substrate Proteins - genetics; Insulin Receptor Substrate Proteins - metabolism; Insulin-Like Growth Factor I - pharmacology; Insulin/IGF-1; Isotope Labeling; Kinase; Mass Spectrometry; Mice; Mice, Knockout; Mitogen-Activated Protein Kinase 3 - metabolism; Phosphopeptides - analysis; Phosphoproteomics; Phosphorylation - drug effects; Protein Kinase C beta - metabolism; Proteome - analysis; Proteome - drug effects; Signal transduction; Signal Transduction - drug effects
• ISSN: 0898-6568; 1873-3913
• DOI: 10.1016/j.cellsig.2018.03.003

Insulin/IGF-1 action is driven by a complex and highly integrated signalling network. Loss-of-function studies indicate that the major insulin/IGF-1 receptor substrate (IRS) proteins, IRS-1 and IRS-2, mediate different biological functions in vitro and in vivo, suggesting specific signalling properties despite their high degree of homology. To identify mechanisms contributing to the differential signalling properties of IRS-1 and IRS-2 in the mediation of insulin/IGF-1 action, we performed comprehensive mass spectrometry (MS)-based phosphoproteomic profiling of brown preadipocytes from wild type, IRS-1−/− and IRS-2−/− mice in the basal and IGF-1-stimulated states. We applied stable isotope labeling by amino acids in cell culture (SILAC) for the accurate quantitation of changes in protein phosphorylation. We found ~10% of the 6262 unique phosphorylation sites detected to be regulated by IGF-1. These regulated sites included previously reported substrates of the insulin/IGF-1 signalling pathway, as well as novel substrates including Nuclear Factor I X and Semaphorin-4B. In silico prediction suggests the protein kinase B (PKB), protein kinase C (PKC), and cyclin-dependent kinase (CDK) as the main mediators of these phosphorylation events. Importantly, we found preferential phosphorylation patterns depending on the presence of either IRS-1 or IRS-2, which was associated with specific sets of kinases involved in signal transduction downstream of these substrates such as PDHK1, MAPK3, and PKD1 for IRS-1, and PIN1 and PKC beta for IRS-2. Overall, by generating a comprehensive phosphoproteomic profile from brown preadipocyte cells in response to IGF-1 stimulation, we reveal both common and distinct insulin/IGF-1 signalling events mediated by specific IRS proteins. •Phosphoproteomic analysis reveals novel elements of the insulin/IGF-1 signalling pathway.•IRS-1 and IRS-2 are essential and complimentary to mediate the full and optimal response to insulin/IGF-1 stimulation•IRS-1 and IRS-2 mediate distinct and specific signalling events•The particular contributions of IRS-1 and IRS-2 are linked to the regulation of specific sets of kinases.