The HSP90/R2TP Quaternary Chaperone Scaffolds Assembly of the TSC Complex

• Published in: Journal of molecular biology 2024-12, Vol.436 (23), p.168840, Article 168840
• Main Authors: Abéza, Claire, Busse, Philipp, Paiva, Ana C.F., Chagot, Marie-Eve, Schneider, Justine, Robert, Marie-Cécile, Vandermoere, Franck, Schaeffer, Christine, Charpentier, Bruno, Sousa, Pedro M.F., Bandeiras, Tiago M., Manival, Xavier, Cianferani, Sarah, Bertrand, Edouard, Verheggen, Céline
• Format: Article
• Language: English
• Subjects: Adaptor Proteins, Signal Transducing - chemistry; Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Apoptosis Regulatory Proteins; ATPases associated with diverse cellular activities (RUVBL1/2); ATPases Associated with Diverse Cellular Activities - chemistry; ATPases Associated with Diverse Cellular Activities - genetics; ATPases Associated with Diverse Cellular Activities - metabolism; Biochemistry, Molecular Biology; Carrier Proteins - chemistry; Carrier Proteins - genetics; Carrier Proteins - metabolism; DNA Helicases - chemistry; DNA Helicases - genetics; DNA Helicases - metabolism; heat shock protein 90 (HSP90); HEK293 Cells; HSP90 Heat-Shock Proteins - chemistry; HSP90 Heat-Shock Proteins - genetics; HSP90 Heat-Shock Proteins - metabolism; Humans; Life Sciences; Molecular biology; Molecular Chaperones - chemistry; Molecular Chaperones - genetics; Molecular Chaperones - metabolism; Protein Binding; R2TP; RNA Helicases - chemistry; RNA Helicases - genetics; RNA Helicases - metabolism; tuberous sclerosis complex (TSC); Tuberous Sclerosis Complex 1 Protein - genetics; Tuberous Sclerosis Complex 1 Protein - metabolism; Tuberous Sclerosis Complex 2 Protein - chemistry; Tuberous Sclerosis Complex 2 Protein - genetics; Tuberous Sclerosis Complex 2 Protein - metabolism
• ISSN: 0022-2836; 1089-8638; 1089-8638
• DOI: 10.1016/j.jmb.2024.168840

[Display omitted] •TSC1 directly interacts with the N-terminal binding pocket of PIH1D1 in a phosphorylation independent manner.•Inhibition of R2TP leads to a reduction of TSC assembly.•HSP90/R2TP assemble not only mTORC1 but also its main regulator, the TSC complex. The R2TP chaperone is composed of the RUVBL1/RUVBL2 AAA+ ATPases and two adapter proteins, RPAP3 and PIH1D1. Together with HSP90, it functions in the assembly of macromolecular complexes that are often involved in cell proliferation. Here, proteomic experiments using the isolated PIH domain reveals additional R2TP partners, including the Tuberous Sclerosis Complex (TSC) and many transcriptional complexes. The TSC is a key regulator of mTORC1 and is composed of TSC1, TSC2 and TBC1D7. We show a direct interaction of TSC1 with the PIH phospho-binding domain of PIH1D1, which is, surprisingly, phosphorylation independent. Via the use of mutants and KO cell lines, we observe that TSC2 makes independent interactions with HSP90 and the TPR domains of RPAP3. Moreover, inactivation of PIH1D1 or the RUVBL1/2 ATPase activity inhibits the association of TSC1 with TSC2. Taken together, these data suggest a model in which the R2TP recruits TSC1 via PIH1D1 and TSC2 via RPAP3 and HSP90, and use the chaperone-like activities of RUVBL1/2 to stimulate their assembly.