Insulin Receptors and Insulin Action in the Heart: The Effects of Left Ventricular Assist Devices

Figures

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  Figure 1. Pathways of insulin signaling in the myocardium. The first step is the activation of the receptors (IGF-1R or IR) by insulin, IGF-1, and IGF-2. All molecules can bind to all receptors, but insulin has a high affinity to the IR, while IGF-1 and IGF-2 have a high affinity to the IGF-1R. After the activation of the receptor, many downstream pathways are subsequently activated, aiming to provide, among others, protein synthesis, cardioprotection, cell growth and size regulation, cell survival, glycogen synthesis, and glyconeogenesis. Abbreviations used: IGF-1: Insulin-like Growth Factor-1, IGF-2: Insulin-like Growth Factor-2, IGF-1R: Insulin-like Growth Factor-1 Receptor, IR: Insulin Receptor, IRS-1/2: Insulin Receptor Substrate 1/2, P: Phosphorylation, Shc: Src homology and collagen adaptor protein, GDP: Guanosine Diphosphate, GTP: Guanosine Triphosphate, Ras: Ras kinase, Raf: Raf kinase, MEK1/2/MAPK: Mitogen Activated Protein Kinase, ERK: Extracellular-signal-regulated Kinase, p85: p85 regulatory subunit, p110: p110 catalytic subunit, PI3K: Phosphoinositide 3-Kinase, PIP2: Phosphatidylinositol 4,5-bisphosphate, PIP3: Phosphatidylinositol (3,4,5)-triphosphate, PTEN: Phosphatase and…

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  Figure 2. Insulin-signaling pathways in endothelial cells. Insulin can lead to either vasodilation or vasoconstriction, depending on the pathway.