The MRN (MRE11-RAD50-NBS1) complex is essential for repair of DNA double-strand breaks and stalled replication forks. Mutations of the MRN complex subunit MRE11 cause the hereditary cancer-susceptibility disease ataxia-telangiectasia-like disorder (ATLD). Here we show that MRE11 directly interacts with PIH1D1, a subunit of heat-shock protein 90 cochaperone R2TP complex, which is required for the assembly of large protein complexes, such as RNA polymerase II, small nucleolar ribonucleoproteins and mammalian target of rapamycin complex 1. The MRE11-PIH1D1 interaction is dependent on casein kinase 2 (CK2) phosphorylation of two acidic sequences within the MRE11 C terminus containing serines 558/561 and 688/689. Conversely, the PIH1D1 phospho-binding domain PIH-N is required for association with MRE11 phosphorylated by CK2. Consistent with these findings, depletion of PIH1D1 resulted in MRE11 destabilization and affected DNA-damage repair processes dependent on MRE11. Additionally, mutations of serines 688/689, which abolish PIH1D1 binding, also resulted in decreased MRE11 stability. As depletion of R2TP frequently leads to instability of its substrates and as truncation mutation of MRE11 lacking serines 688/689 leads to decreased levels of the MRN complex both in ATLD patients and an ATLD mouse model, our results suggest that the MRN complex is a novel R2TP complex substrate and that their interaction is regulated by CK2 phosphorylation.

• MeSH
• ATM protein metabolismus   MeSH
• buněčné jádro metabolismus   MeSH
• DNA vazebné proteiny metabolismus   MeSH
• enzymy opravy DNA metabolismus   MeSH
• fosforylace fyziologie   MeSH
• jaderné proteiny metabolismus   MeSH
• kaseinkinasa II metabolismus   MeSH
• lidé MeSH
• mutace fyziologie   MeSH
• myši MeSH
• oprava DNA fyziologie   MeSH
• poškození DNA fyziologie   MeSH
• proteiny regulující apoptózu metabolismus   MeSH
• proteiny teplotního šoku metabolismus   MeSH
• ribonukleoproteiny malé jadérkové metabolismus   MeSH
• RNA-polymerasa II metabolismus   MeSH
• serin metabolismus   MeSH
• teleangiektatická ataxie metabolismus   MeSH
• TOR serin-threoninkinasy metabolismus   MeSH
• vazba proteinů fyziologie   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The R2TP complex is a HSP90 co-chaperone, which consists of four subunits: PIH1D1, RPAP3, RUVBL1, and RUVBL2. It is involved in the assembly of large protein or protein-RNA complexes such as RNA polymerase, small nucleolar ribonucleoproteins (snoRNPs), phosphatidylinositol 3 kinase-related kinases (PIKKs), and their complexes. While RPAP3 has a HSP90 binding domain and the RUVBLs comprise ATPase activities important for R2TP functions, PIH1D1 contains a PIH-N domain that specifically recognizes phosphorylated substrates of the R2TP complex. In this review we provide an overview of the current knowledge of the R2TP complex with the focus on the recently identified structural and mechanistic features of the R2TP complex functions. We also discuss the way R2TP regulates cellular response to stress caused by low levels of nutrients or by DNA damage and its possible exploitation as a target for anti-cancer therapy.

• Publikační typ
• časopisecké články MeSH
• přehledy MeSH

Splicing is catalyzed by the spliceosome, a complex of five major small nuclear ribonucleoprotein particles (snRNPs). The pre-mRNA splicing factor PRPF8 is a crucial component of the U5 snRNP, and together with EFTUD2 and SNRNP200, it forms a central module of the spliceosome. Using quantitative proteomics, we identified assembly intermediates containing PRPF8, EFTUD2, and SNRNP200 in association with the HSP90/R2TP complex, its ZNHIT2 cofactor, and additional proteins. HSP90 and R2TP bind unassembled U5 proteins in the cytoplasm, stabilize them, and promote the formation of the U5 snRNP. We further found that PRPF8 mutants causing Retinitis pigmentosa assemble less efficiently with the U5 snRNP and bind more strongly to R2TP, with one mutant retained in the cytoplasm in an R2TP-dependent manner. We propose that the HSP90/R2TP chaperone system promotes the assembly of a key module of U5 snRNP while assuring the quality control of PRPF8. The proteomics data further reveal new interactions between R2TP and the tuberous sclerosis complex (TSC), pointing to a potential link between growth signals and the assembly of key cellular machines.

• MeSH
• elongační faktory genetika   metabolismus   MeSH
• HeLa buňky MeSH
• interakční proteinové domény a motivy MeSH
• lidé MeSH
• malý jaderný ribonukleoprotein U1 metabolismus   MeSH
• malý jaderný ribonukleoprotein U4-U6 metabolismus   MeSH
• malý jaderný ribonukleoprotein U5 genetika   metabolismus   MeSH
• messenger RNA genetika   metabolismus   MeSH
• multiproteinové komplexy MeSH
• mutace MeSH
• prekurzory RNA genetika   metabolismus   MeSH
• proteiny tepelného šoku HSP90 metabolismus   MeSH
• proteiny vázající RNA genetika   metabolismus   MeSH
• proteiny vázající vápník metabolismus   MeSH
• proteomika metody   MeSH
• retinopathia pigmentosa genetika   metabolismus   MeSH
• RNA interference MeSH
• sestřih RNA * MeSH
• stabilita proteinů MeSH
• transfekce MeSH
• vazba proteinů MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH