Membrane association of the PTEN tumor suppressor: Electrostatic interaction with phosphatidylserine-containing bilayers and regulatory role of the C-terminal tail
| Autor: | Mathias Lösche, Siddharth Shenoy, Hirsh Nanda |
|---|---|
| Rok vydání: | 2012 |
| Předmět: |
Lipid Bilayers
Static Electricity Phosphatidylserines Plasma protein binding Molecular Dynamics Simulation Article Protein Structure Secondary Protein structure Structural Biology Scattering Small Angle Humans PTEN Lipid bilayer PI3K/AKT/mTOR pathway C2 domain Binding Sites biology Chemistry PTEN Phosphohydrolase Protein Structure Tertiary Neutron Diffraction Membrane Biochemistry Protein body Phosphatidylcholines Biophysics biology.protein Protein Binding |
| Zdroj: | Journal of Structural Biology. 180:394-408 |
| ISSN: | 1047-8477 |
| DOI: | 10.1016/j.jsb.2012.10.003 |
| Popis: | The phosphatidylinositolphosphate phosphatase PTEN is the second most frequently mutated protein in human tumors. Its membrane association, allosteric activation and membrane dissociation are poorly understood. We recently reported PTEN binding affinities to membranes of different compositions (Shenoy et al., 2012, PLoS ONE 7, e32591) and a preliminary investigation of the protein-membrane complex with neutron reflectometry (NR). Here we use NR to validate molecular dynamics (MD) simulations of the protein and study conformational differences of the protein in solution and on anionic membranes. NR shows that full-length PTEN binds to such membranes roughly in the conformation and orientation suggested by the crystal structure of a truncated PTEN protein, in contrast with a recently presented model which suggested that membrane binding depends critically on the SUMOylation of the CBR3 loop of PTEN's C2 domain. Our MD simulations confirm that PTEN is peripherally bound to the bilayer surface and show slight differences of the protein structure in solution and in the membrane-bound state, where the protein body flattens against the bilayer surface. PTEN's C2 domain binds phosphatidylserine (PS) tightly through its CBR3 loop, and its phosphatase domain also forms electrostatic interactions with PS. NR and MD results show consistently that PTEN's unstructured, anionic C-terminal tail is repelled from the bilayer surface. In contrast, this tail is tightly tugged against the C2 domain in solution, partially obstructing the membrane-binding interface of the protein. Arresting the C-terminal tail in this conformation by phosphorylation may provide a control mechanism for PTEN's membrane binding and activity. |
| Databáze: | OpenAIRE |
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