Figure 1710

Diagram of intracellular signaling pathways mediated by the insulin-like growth factor I (IGF-IR) receptor. IGF-IR when bound to IGF-I undergoes autophosphorylation on its tyrosine residues. This enhances its intrinsic tyrosine kinase activity and phosphorylates multiple substrates, including insulin receptor substrate 1 (IRS-1), IRS-2, and Src homology/collagen (SHC). IRS-1 upon phosphorylation associates with the p85 subunit of the PI3-kinase (PI3K) and phos-phorylates PI3-kinase. PI3K upon phospho-rylation converts phosphoinositide-3 phosphate (PI-3P) into PI-3,4-P2, which in turn activates a serine-thronine kinase Akt (protein kinase B). Activated Akt kinase phos-phorylates the proapoptotic factor Bad on a serine residue, resulting in its dissociation from B-cell lymphoma-X (Bc1-Xl) . The released Bc1-Xl is then capable of suppressing cell death pathways that involve the activity of apoptosis protease activating factor (Apaf-1), cytochrome C, and caspases. A number of growth factors, including platelet-derived growth factor (PDGF) and IGF 1 promotes cell survival. Activation of the PI3K cascade is one of the mechanisms by which growth factors mediate cell survival. Phosphorylated IRS-1 also associates with growth factor receptor bound protein 2 (Grb2), which bind son of sevenless (Sos) and activates the ras-raf-mitogen activated protein (ras/raf-MAP) kinase cascade. SHC also binds Grb2/Sos and activates the ras/raf-MAP kinase cascade. Other substrates for IGF-I are phosphotyrosine phos-phatases and SH2 domain containing tyro-sine phosphatase (Syp). Figure 17-7 has details on the other signaling pathways in this figure. MBP—myelin basic protein; nck—an adaptor protein composed of SH2 and SH3 domains; TF—transcription factor.

Supplements For Diabetics

Supplements For Diabetics

All you need is a proper diet of fresh fruits and vegetables and get plenty of exercise and you'll be fine. Ever heard those words from your doctor? If that's all heshe recommends then you're missing out an important ingredient for health that he's not telling you. Fact is that you can adhere to the strictest diet, watch everything you eat and get the exercise of amarathon runner and still come down with diabetic complications. Diet, exercise and standard drug treatments simply aren't enough to help keep your diabetes under control.

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