key term - Pi3k/akt pathway

Definition

The PI3K/Akt pathway is a crucial signaling pathway in cells that is involved in regulating various cellular processes, including growth, survival, and metabolism. This pathway is activated by various growth factors and hormones, leading to a cascade of events that promote cellular functions like protein synthesis and glucose metabolism, ultimately influencing cell proliferation and survival.

5 Must Know Facts For Your Next Test

1. Activation of the PI3K/Akt pathway begins when growth factors bind to their receptors, leading to the recruitment and activation of PI3K.
2. Once activated, PI3K converts phosphatidylinositol 4,5-bisphosphate (PIP2) into PIP3, which facilitates the recruitment of Akt to the plasma membrane.
3. Akt gets fully activated through phosphorylation by PDK1 and mTORC2, allowing it to carry out its functions.
4. The PI3K/Akt pathway has critical roles in cancer biology, as its dysregulation can lead to enhanced cell survival and uncontrolled growth.
5. In addition to regulating cell growth and survival, Akt also influences glucose metabolism by promoting the translocation of glucose transporters to the cell membrane.

Review Questions

• How does the activation of the PI3K/Akt pathway influence cellular processes?
  • The activation of the PI3K/Akt pathway influences cellular processes by promoting cell growth, survival, and metabolism. When growth factors bind to their receptors, they activate PI3K, leading to the production of PIP3. This activates Akt, which then phosphorylates various target proteins that regulate essential functions such as protein synthesis, glucose uptake, and apoptosis inhibition. Through these mechanisms, the pathway ensures that cells respond appropriately to external signals.
• Evaluate the role of Akt within the PI3K/Akt signaling cascade and its implications for cancer therapy.
  • Akt plays a pivotal role within the PI3K/Akt signaling cascade as it is a key effector that mediates various downstream effects of this pathway. Its ability to promote cell survival and proliferation means that when Akt is overactive or dysregulated, it can contribute to tumorigenesis. Targeting Akt in cancer therapy has become an area of interest since inhibiting its activity may restore normal apoptotic pathways and reduce tumor growth. However, developing effective inhibitors presents challenges due to feedback loops within the signaling network.
• Synthesize information on how dysregulation of the PI3K/Akt pathway can lead to metabolic disorders.
  • Dysregulation of the PI3K/Akt pathway can lead to metabolic disorders due to its central role in regulating glucose metabolism and energy balance. For example, hyperactivation of this pathway can result in insulin resistance, as excessive Akt activity may interfere with insulin signaling pathways responsible for glucose uptake. Additionally, impaired regulation can contribute to obesity and type 2 diabetes by disrupting normal metabolic homeostasis. Understanding these connections helps researchers develop targeted therapies aimed at correcting these metabolic imbalances.

Related terms

Phosphatidylinositol 3-kinase (PI3K): An enzyme that phosphorylates the inositol ring of phosphatidylinositol, producing phosphatidylinositol-3-phosphate (PIP3), which is a key second messenger in the PI3K/Akt pathway.

Akt (Protein Kinase B): A serine/threonine kinase that plays a central role in the PI3K/Akt signaling pathway, involved in promoting cell survival and growth by phosphorylating various substrates.

mTOR: Mammalian target of rapamycin, a key regulator of cell growth and metabolism that is downstream of the PI3K/Akt pathway, integrating signals from nutrients and growth factors.