PI(3,5)P 2 Controls the Signaling Activity of Class I PI3K
Biorxiv : the Preprint Server for Biology
|February 7, 2023
Summary
Researchers developed a new sensor to visualize phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2) dynamics. This lipid regulates growth factor signaling, impacting cancer and tissue regeneration.
Area of Science:
- Cellular lipid signaling
- Molecular mechanisms of cancer
- Phosphoinositide metabolism
Background:
- 3-Phosphoinositides are critical cellular lipids involved in various physiological processes.
- Phosphatidylinositol-3,5-bisphosphate (PI(3,5)P2) function is poorly understood due to limited imaging tools.
- Class I PI3K is frequently mutated in cancer, driving uncontrolled cell growth.
Purpose of the Study:
- To develop a novel sensor for spatiotemporally resolved imaging of PI(3,5)P2.
- To elucidate the role of PI(3,5)P2 in regulating growth factor signaling pathways.
- To investigate the therapeutic potential of targeting PI(3,5)P2-mediated feedback loops in cancer.
Main Methods:
- Engineered a ratiometric PI(3,5)P2 sensor from the PI3K-p85α subunit.
- Utilized quantitative imaging to track PI(3,5)P2 generation on endosomes/lysosomes.
- Employed small molecule inhibitors to probe PI(3,5)P2-p85α interactions.
Main Results:
- Identified a unique pool of PI(3,5)P2 generated on lysosomes/late endosomes upon growth factor stimulation.
- Demonstrated that PI(3,5)P2, mediated by PI3KC2β and PIKfyve, negatively regulates Class I PI3K activity.
- Showed that cancer-associated mutations in PI3K-p85 disrupt PI(3,5)P2 binding, leading to sustained PI3K activation.
Conclusions:
- Uncovered a novel feedback mechanism linking PI(3,5)P2 to Class I PI3K regulation.
- Established PI(3,5)P2 as a key modulator of PI3K-mediated growth factor signaling.
- Proposed therapeutic strategies targeting PI(3,5)P2-p85 interactions for cancer treatment and tissue regeneration.
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