Insulin Resistance | Basics and Mechanism | Basic Science Series

Basic Science Series
Basic Science Series
416 بار بازدید - 3 ماه پیش - Insulin Resistance | Basics and
Insulin Resistance | Basics and Mechanism | Basic Science Series

Insulin resistance, a hallmark of type 2 diabetes, stems from a complex interplay of molecular mechanisms within cells.
At the cellular level, insulin binds to its receptor, initiating a cascade of events crucial for glucose uptake. The insulin receptor substrate (IRS) proteins are phosphorylated upon insulin binding, facilitating the activation of downstream signaling pathways.
One of the key pathways affected by insulin resistance is the phosphoinositide 3-kinase (PI3K)/Akt pathway. Activation of PI3K leads to the production of phosphatidylinositol-3,4,5-trisphosphate (PIP3), which in turn recruits Akt to the plasma membrane. Akt activation promotes the translocation of glucose transporter proteins, such as GLUT4, to the cell membrane, facilitating glucose uptake.
In type 2 diabetes, insulin resistance disrupts this pathway at multiple levels. Increased serine phosphorylation of IRS proteins by various kinases, such as c-Jun N-terminal kinase (JNK) and inhibitor of nuclear factor kappa-B kinase subunit beta (IKK-β), leads to their degradation and inhibits downstream signaling.
Furthermore, elevated levels of circulating free fatty acids, characteristic of obesity and insulin resistance, activate protein kinase C (PKC) isoforms. PKC activation impairs insulin signaling by phosphorylating IRS proteins and interfering with Akt activation.
Additionally, the mammalian target of rapamycin complex 1 (mTORC1) pathway, which integrates nutrient and hormonal signals to regulate cell growth and metabolism, has been implicated in insulin resistance. Hyperactivation of mTORC1 in obesity disrupts insulin signaling and promotes insulin resistance by inhibiting IRS-1 function and impairing Akt activation.
Moreover, dysregulation of mitogen-activated protein kinase (MAPK) pathways, particularly the extracellular signal-regulated kinase (ERK) pathway, contributes to insulin resistance. Chronic activation of ERK signaling in obesity leads to serine phosphorylation of IRS proteins, inhibiting their function and impairing insulin signaling.
Collectively, these molecular alterations in cellular signaling pathways contribute to insulin resistance in type 2 diabetes. Understanding these intricate mechanisms provides insights into potential therapeutic targets for the prevention and management of the disease.
Keywords:
insulin resistance, type 2 diabetes, molecular mechanisms, cellular level, insulin receptor, insulin receptor substrate (IRS), phosphoinositide 3-kinase (PI3K), Akt pathway, glucose uptake, phosphatidylinositol-3,4,5-trisphosphate (PIP3), GLUT4, serine phosphorylation, c-Jun N-terminal kinase (JNK), inhibitor of nuclear factor kappa-B kinase subunit beta (IKK-β), free fatty acids, protein kinase C (PKC), mammalian target of rapamycin complex 1 (mTORC1), mitogen-activated protein kinase (MAPK), extracellular signal-regulated kinase (ERK), obesity, therapeutic targets
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3 ماه پیش در تاریخ 1403/02/01 منتشر شده است.
416 بـار بازدید شده
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