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Updated: Jun 21, 2026
12:42
Photoactivated Localization Microscopy with Bimolecular Fluorescence Complementation (BiFC-PALM)
Published on: December 22, 2015
Visualization of Ras-PI3K interaction in the endosome using BiFC
Kaori Tsutsumi1, Yoichiro Fujioka, Masumi Tsuda
1Laboratory of Pathophysiology and Signal Transduction, Hokkaido University Graduate School of Medicine, N15W7, Kita-ku, Sapporo 060-8638, Japan.
Cellular Signalling
|July 21, 2009
Summary
Ras-phosphatidylinositol 3-kinase (PI3K) signaling locally regulates endosomal phosphatidylinositol metabolism. This study identifies PI3K as a key effector specifically involved in endosomal signaling, crucial for cellular communication.
Area of Science:
- Cellular Biology
- Molecular Signaling
- Endosomal Trafficking
Background:
- Spatiotemporal regulation is critical for intracellular signaling diversity and specificity.
- The role of Ras-PI3K signaling in endosomal compartments requires further elucidation.
Purpose of the Study:
- To investigate the role of Ras-PI3K signaling in the local regulation of phosphatidylinositol metabolism within endosomes.
- To identify specific Ras effectors involved in endosomal signaling pathways.
Main Methods:
- Live-cell imaging utilizing a bimolecular fluorescence complementation (BiFC) technique to visualize molecular interactions.
- Development and optimization of Ras and Ras-binding domain probe combinations for sensitive detection of Ras activity.
- Analysis of phosphatidylinositol 3-kinase (PI3K) recruitment and activation in response to epidermal growth factor (EGF) and Ras.
Main Results:
- The optimized BiFC probes revealed significant fluorescence changes indicating Ras activity.
- Phosphatidylinositol 3-kinase (PI3K) was identified as a specific effector implicated in endosomal signaling.
- Full-length PI3K recruitment to the endosome was dependent on EGF and Ras, essential for PI3K activation.
Conclusions:
- Ras-PI3K signaling is spatiotemporally regulated within the endosome.
- This localized signaling pathway dictates PI3K activation and subsequent downstream signaling events in the endosome.
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