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Woodford MR, Sager RA, Marris E, Dunn DM, Blanden AR, Murphy RL, Rensing N, Shapiro O, Panaretou B, Prodromou C, Loh SN, Gutmann DH, Bourboulia D, Bratslavsky G, Wong M, Mollapour M. Tumor suppressor Tsc1 is a new Hsp90 co-chaperone that facilitates folding of kinase and non-kinase clients. EMBO J 2017; 36:3650-3665. [PMID: 29127155 PMCID: PMC5730846 DOI: 10.15252/embj.201796700] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Revised: 09/15/2017] [Accepted: 10/02/2017] [Indexed: 12/29/2022] Open
Abstract
The tumor suppressors Tsc1 and Tsc2 form the tuberous sclerosis complex (TSC), a regulator of mTOR activity. Tsc1 stabilizes Tsc2; however, the precise mechanism involved remains elusive. The molecular chaperone heat‐shock protein 90 (Hsp90) is an essential component of the cellular homeostatic machinery in eukaryotes. Here, we show that Tsc1 is a new co‐chaperone for Hsp90 that inhibits its ATPase activity. The C‐terminal domain of Tsc1 (998–1,164 aa) forms a homodimer and binds to both protomers of the Hsp90 middle domain. This ensures inhibition of both subunits of the Hsp90 dimer and prevents the activating co‐chaperone Aha1 from binding the middle domain of Hsp90. Conversely, phosphorylation of Aha1‐Y223 increases its affinity for Hsp90 and displaces Tsc1, thereby providing a mechanism for equilibrium between binding of these two co‐chaperones to Hsp90. Our findings establish an active role for Tsc1 as a facilitator of Hsp90‐mediated folding of kinase and non‐kinase clients—including Tsc2—thereby preventing their ubiquitination and proteasomal degradation.
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Affiliation(s)
- Mark R Woodford
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, USA.,Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Rebecca A Sager
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, USA.,Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA.,Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Elijah Marris
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, USA.,Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA.,Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Diana M Dunn
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, USA.,Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA.,Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Adam R Blanden
- Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA.,Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Ryan L Murphy
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, USA.,Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Nicholas Rensing
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA.,Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Oleg Shapiro
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, USA.,Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Barry Panaretou
- Institute of Pharmaceutical Science, King's College London, London, UK
| | | | - Stewart N Loh
- Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA.,Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - David H Gutmann
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA
| | - Dimitra Bourboulia
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, USA.,Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA.,Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Gennady Bratslavsky
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, USA.,Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Michael Wong
- Department of Neurology, Washington University School of Medicine, St. Louis, MO, USA.,Hope Center for Neurological Disorders, Washington University School of Medicine, St. Louis, MO, USA
| | - Mehdi Mollapour
- Department of Urology, SUNY Upstate Medical University, Syracuse, NY, USA .,Upstate Cancer Center, SUNY Upstate Medical University, Syracuse, NY, USA.,Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
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