Tumor suppressor PTEN acts through dynamic interaction with the plasma membrane.
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.
Department of Cell Biology, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
Francisca
F
Vazquez
Satomi
S
Matsuoka
William R
WR
Sellers
Toshio
T
Yanagida
Masahiro
M
Ueda
Peter N
PN
Devreotes
D020816:Amino Acid Motifs; D000818:Animals; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism; D001665:Binding Sites; D002460:Cell Line; D002462:Cell Membrane / Q000378:metabolism*; D016764:Cell Polarity; D004023:Dictyostelium / Q000235:genetics / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008856:Microscopy, Fluorescence; D051059:PTEN Phosphohydrolase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D011487:Protein Conformation; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D017384:Sequence Deletion
D001426:Bacterial Proteins; D008164:Luminescent Proteins; D018129:Phosphatidylinositol Phosphates; D015800:Protozoan Proteins; D011993:Recombinant Fusion Proteins; C060974:phosphatidylinositol 3,4,5-triphosphate; C054562:yellow fluorescent protein, Bacteria; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human