Phosphorylation-mediated PTEN conformational closure and deactivation revealed with protein semisynthesis

David Bolduc, Meghdad Rahdar, Becky Tu-Sekine, Sindhu Carmen Sivakumaren, Daniel Raben, L. Mario Amzel, Peter Devreotes, Sandra B. Gabelli, Philip Cole

Research output: Contribution to journalArticle

Abstract

The tumor suppressor PIP3 phosphatase PTEN is phosphorylated on four clustered Ser/Thr on its C-terminal tail (aa 380-385) and these phosphorylations are proposed to induce a reduction in PTEN's plasma membrane recruitment. How these phosphorylations affect the structure and enzymatic function of PTEN is poorly understood. To gain insight into the mechanistic basis of PTEN regulation by phosphorylation, we generated semisynthetic site-specifically tetra-phosphorylated PTEN using expressed protein ligation. By employing a combination of biophysical and enzymatic approaches, we have found that purified tail-phosphorylated PTEN relative to its unphosphorylated counterpart shows reduced catalytic activity and membrane affinity and undergoes conformational compaction likely involving an intramolecular interaction between its C-tail and the C2 domain. Our results suggest that there is a competition between membrane phospholipids and PTEN phospho-tail for binding to the C2 domain. These findings reveal a key aspect of PTEN's regulation and suggest pharmacologic approaches for direct PTEN activation.

Original languageEnglish (US)
Article numbere00691
JournaleLife
Volume2013
Issue number2
DOIs
StatePublished - Jul 9 2013

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ASJC Scopus subject areas

  • Neuroscience(all)
  • Immunology and Microbiology(all)
  • Biochemistry, Genetics and Molecular Biology(all)

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