Metabolic Disturbance in PCOS: Clinical and Molecular Effects on Skeletal Muscle Tissue

Figure 4

In brief, the insulin binds with its membrane receptor which has intrinsic tyrosine kinase activity, triggers a signaling cascade to downstream substrates resulting in glucose transport. Subsequently, tyrosine phosphorylated IRS (IRS-1/2) recruits signaling molecules incluinding phosphoinositide 3-kinase (PI3k). After a activation of PI3k a complex formation ofphosphatidylinositol-3,4,5-trisphosphate (PI3P) that serves as regulator of phosphoinositide-dependent kinase (PDK) which was later shown to activate others prototypes proteins kinase (e.g., PKC). With this, the protein Akt is activated and propagates the hormonal signal to activate protein AS160 (GTPase activating protein of 160 kDa), which in turn sensitizes the glucose transporter in skeletal muscle (GLUT-4) to the translocation process to the lipid membrane to glucose uptake [38].