Kinetics of PTEN-mediated PI(3,4,5)P3 hydrolysis on solid supported membranes
Abstract
Phosphatidylinositides play important roles in cellular signaling and migration. Phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3) is an important phosphatidylinositide because it acts as a secondary messenger to trigger cell movement and proliferation. A high level of PI(3,4,5)P3 at the plasma membrane is known to contribute to tumorigenesis. One key enzyme that regulates PI(3,4,5)P3 levels at the plasma membrane is phosphatase and tensin homologue deleted on chromosome 10 (PTEN), which dephosphorylates PI(3,4,5)P3 through hydrolysis to form phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2). It has been reported that PI(4,5)P2 is involved in positive feedback in the PI(3,4,5)P3 hydrolysis by PTEN. However, how PI(3,4,5)P3 dephosphorylation by PTEN is regulated, is still under debate. How other PI(3,4,5)P3-binding proteins affect the dephosphorylation kinetics catalyzed by PTEN also remains unclear. Here, we develop a fluorescent-protein biosensor approach to study how PI(3,4,5)P3 dephosphorylation is regulated by PTEN as well as its membrane-mediated feedback mechanisms. Our observation of sigmoidal kinetics of the PI(3,4,5)P3 hydrolysis reaction supports the notion of autocatalysis in PTEN function. We developed a kinetic model to describe the observed reaction kinetics, which allowed us to i) distinguish between membrane-recruitment and allosteric activation of PTEN by PI(4,5)P2, ii) account for the influence of the biosensor on the observed reaction kinetics, and iii) demonstrate that all of these mechanisms contribute to the kinetics of PTEN-mediated catalysis.
Additional Information
© 2018 Liu et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Received: October 25, 2017; Accepted: January 26, 2018; Published: February 15, 2018. Data Availability Statement: All relevant data are within the paper and its Supporting Information files. This work was supported by National Science Foundation (NSF) CAREER grant CBET 1053857 and National Institutes of Health (NIH) grant R01 97552 (to TB). The authors have declared that no competing interests exist. We acknowledge help with enzyme purification from the labs of A. Ross and R. Marmorstein, thank L. Xinle, L. Chun-Wei, Z. Graber, and S. Wilner for helpful discussions, and acknowledge funding through NSF CAREER grant CBET 1053857 and NIH grant R01 97552. Author Contributions: Conceptualization: Tobias Baumgart. Formal analysis: Chun Liu. Funding acquisition: Tobias Baumgart. Investigation: Chun Liu, Sanghamitra Deb, Vinicius S. Ferreira, Eric Xu. Methodology: Chun Liu, Sanghamitra Deb, Vinicius S. Ferreira, Tobias Baumgart. Project administration: Tobias Baumgart. Resources: Chun Liu, Sanghamitra Deb, Vinicius S. Ferreira, Eric Xu. Software: Chun Liu. Supervision: Tobias Baumgart. Validation: Chun Liu. Visualization: Chun Liu. Writing ± original draft: Chun Liu, Sanghamitra Deb, Tobias Baumgart. Writing ± review & editing: Chun Liu, Tobias Baumgart.Attached Files
Published - journal.pone.0192667.pdf
Supplemental Material - journal.pone.0192667.s001.pdf
Supplemental Material - journal.pone.0192667.s002.pdf
Supplemental Material - journal.pone.0192667.s003.pdf
Supplemental Material - journal.pone.0192667.s004.pdf
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Additional details
- PMCID
- PMC5813967
- Eprint ID
- 85314
- Resolver ID
- CaltechAUTHORS:20180314-151153676
- CBET-1053857
- NSF
- R01 97552
- NIH
- Created
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2018-03-15Created from EPrint's datestamp field
- Updated
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2019-10-03Created from EPrint's last_modified field