Details

Autor(en) / Beteiligte

• Marshall, Jeremy
• Mellor, Paul
• Ruan, Xuan
• Whitecross, Dielle
• Moore, Stanley
• Anderson, Deborah

Titel

Abstract 3461: Characterizing the PTEN - p85alpha interaction

Ist Teil von

• Cancer research (Chicago, Ill.), 2019-07, Vol.79 (13_Supplement), p.3461-3461

Erscheinungsjahr

2019

Link zum Volltext

Quelle

EZB Electronic Journals Library

Beschreibungen/Notizen

• Abstract Introduction: The phosphatidylinositol 3-kinase (PI3K) pathway plays a key role in regulating cell growth and cell survival and is frequently deregulated in cancer cells. p85α regulates the p110α lipid kinase, and also stabilizes and stimulates PTEN, the lipid phosphatase that downregulates this pathway. We set out to identify residues in both PTEN and p85α that mediate their interaction to better understand the regions important in mediating binding. Experimental Procedures: We previously showed that the BH domain of p85α is sufficient to mediate binding to PTEN. In this work, a deletion analysis and point mutations were used to mutate each of PTEN and the p85α BH domain to identify residues important for binding, determined using a pull-down analysis. Mutations in the p85α BH domain and in PTEN that reduced their interaction were then used as input data and docking software was used to model possible interaction interfaces for the two the proteins. Further mutagenesis and follow-up binding experiments provided support for our model of the PTEN - p85α BH domain complex. Results: We identified key residues responsible for mediating PTEN - p85α complex formation. Based on these experimental results, a docking model for the PTEN - p85α BH domain complex was developed that is consistent with the known binding interactions for both PTEN and p85α. This model involves extensive side-chain and peptide backbone contacts between both the PASE (R84, Q87, Y88, E91, E99) and C2 (R189, P190, Q219, C250, D252) domains of PTEN and the p85α BH domains with a buried surface area of 1211 Å2 (PTEN - bovine p85α BH) and 1366 Å2 (PTEN - human p85α BH). The p85α BH domain residues that directly contact PTEN in the two docking models were not identical, however both models implicated p85α residues E212, Q221, K225, R228, H234 and W237. The majority of these p85α BH domain residues were confirmed experimentally as important for PTEN binding. We also verified experimentally the importance of PTEN-E91 in mediating interaction with the p85α BH domain. Conclusions: These results shed new light on the mechanism of PTEN binding and regulation by p85α. Citation Format: Jeremy Marshall, Paul Mellor, Xuan Ruan, Dielle Whitecross, Stanley Moore, Deborah Anderson. Characterizing the PTEN - p85alpha interaction [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3461.