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PTEN functions by recruitment to cytoplasmic vesicles
Adam Naguib1, Gyula Bencze1, Hyejin Cho1
1Cold Spring Harbor Laboratory, Cold Spring Harbor, NY 11724, USA.
Molecular Cell
|April 14, 2015
Summary
Cytoplasmic PTEN localizes to endosomal vesicles via PI(3)P binding, regulating PI 3-kinase/AKT signaling. This reveals a novel mechanism for PTEN activation and signal termination on endosomes.
Area of Science:
- Cell Biology
- Molecular Biology
- Biochemistry
Background:
- PTEN (phosphatase and tensin homolog) is a tumor suppressor.
- PTEN is known to inhibit PI 3-kinase/AKT signaling.
- PTEN's localization and activation mechanisms are not fully understood.
Purpose of the Study:
- To investigate the subcellular localization and activation mechanism of cytoplasmic PTEN.
- To identify the specific molecular interactions mediating PTEN's function.
- To elucidate PTEN's role in regulating PI 3-kinase/AKT signaling.
Main Methods:
- Immunofluorescence microscopy to visualize PTEN localization.
- Biochemical assays to study PTEN binding to PI(3)P.
- Site-directed mutagenesis to disrupt PTEN-PI(3)P interaction.
- Rescue experiments using FYVE domain fusion.
Main Results:
- Cytoplasmic PTEN localizes to endosomal vesicles via PI(3)P binding.
- The C2 domain's CBR3 loop is critical for PI(3)P binding.
- Disruption of PI(3)P binding abrogates PTEN's inhibitory effect on PI 3-kinase/AKT.
- Targeting PTEN to endosomes is functionally important for its activity.
Conclusions:
- PTEN is activated on endosomal membranes through PI(3)P binding.
- This mechanism contrasts with PI 3-kinase activation on the plasma membrane.
- PTEN plays a crucial role in signal termination on internalized vesicles.
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