Related Experiment Video
Updated: Aug 9, 2026
The Soft Agar Colony Formation Assay
Published on: October 27, 2014
Tumor suppressor PTEN acts through dynamic interaction with the plasma membrane
Francisca Vazquez1, Satomi Matsuoka, William R Sellers
1Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Abstract:
The tumor suppressor function of PTEN is strongly linked to its ability to dephosphorylate phosphatidylinositol-3,4,5 trisphosphate and, thereby, control cell growth, survival, and migration. However, the mechanism of action of PTEN in living cells is largely unexplored. Here we use single-molecule TIRF microscopy in living cells to reveal that the enzyme binds to the membrane for a few hundred milliseconds, sufficient to degrade several phosphatidylinositol-3,4,5 trisphosphate molecules. Deletion of an N-terminal lipid-binding motif completely abrogates membrane interaction and in vivo function. Several mechanisms, including C-terminal tail phosphorylations, appear to hold PTEN in a constrained conformation that limits its rate of association with the membrane. The steady-state level of bound PTEN is highest at sites of retracting membrane, including the rear of highly polarized cells. The dynamic membrane association could be modulated temporally or spatially to alter PTEN activity in specific physiological situations and could have important implications for tumor suppressor function.
Insights
The phosphatase and tensin homolog (PTEN) enzyme interacts with cell membranes briefly, degrading key signaling molecules. This dynamic membrane binding is crucial for PTEN
Area of Science:
- Molecular Biology
- Cell Biology
- Biochemistry
Background:
- The tumor suppressor protein PTEN (phosphatase and tensin homolog) regulates cell growth, survival, and migration by dephosphorylating phosphatidylinositol-3,4,5 trisphosphate (PIP3).
- The precise mechanism by which PTEN functions within living cells remains largely uncharacterized.
Purpose of the Study:
- To elucidate the dynamic mechanism of PTEN action at the cell membrane in living cells.
- To investigate the role of membrane interaction in PTEN's tumor suppressor function.
Main Methods:
- Utilized single-molecule total internal reflection fluorescence (TIRF) microscopy in living cells.
- Investigated the impact of deleting an N-terminal lipid-binding motif on PTEN membrane interaction and function.
- Examined the influence of C-terminal tail phosphorylations on PTEN conformation and membrane association.
Main Results:
- PTEN transiently binds to the cell membrane for several hundred milliseconds, enabling the degradation of multiple PIP3 molecules.
- Ablation of the N-terminal lipid-binding motif abolished PTEN's membrane interaction and in vivo functionality.
- PTEN's membrane association is regulated by its conformation, influenced by C-terminal phosphorylations, and is highest at retracting membrane sites.
Conclusions:
- PTEN's tumor suppressor activity is mediated by dynamic, transient membrane interactions.
- The rate and duration of PTEN membrane binding are critical for its enzymatic function and can be modulated.
- Understanding PTEN's dynamic membrane association offers insights into its role in cancer and potential therapeutic strategies.
Related Concept Videos
02:23Abnormal Proliferation
01:12Loss of Tumor Suppressor Gene Functions
When the tumor suppressor genes develop mutations or are lost, cells start growing out of control, leading to cancer. However, a single functional copy of the tumor suppressor gene is enough for the cells to maintain their normal functions and cell...
01:05Cancer-Critical Genes II: Tumor Suppressor Genes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...
01:19Interactions Between Signaling Pathways
Convergence and divergence, and cross-talk between signaling pathways
Two distinct signaling pathways can converge on a single functional unit, which may either be a single protein or a complex of proteins. The response is either functionally distinct or synergistic between the two pathways but different from the response...
01:22PI3K/mTOR/AKT Signaling Pathway
01:05Cancer-Critical Genes II: Tumor Suppressor Genes
When the function of certain critical genes, especially those involved in cell cycle regulation and cell growth signaling cascades, gets disrupted, it upsets the cell cycle progression. Such cells with unchecked cell cycles start proliferating uncontrollably and eventually develop into tumors.
Such genes that act...