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The ATP-bound conformation of the Mre11-Rad50 complex is essential for Tel1/ATM activation.
Nucleic Acids Res. 2019 04 23; 47(7):3550-3567.NA

Abstract

Activation of the checkpoint protein Tel1 requires the Mre11-Rad50-Xrs2 (MRX) complex, which recruits Tel1 at DNA double-strand breaks (DSBs) through direct interaction between Tel1 and Xrs2. However, in vitro Tel1 activation by MRX requires ATP binding to Rad50, suggesting a role also for the MR subcomplex in Tel1 activation. Here we describe two separation-of-functions alleles, mre11-S499P and rad50-A78T, which we show to specifically affect Tel1 activation without impairing MRX functions in DSB repair. Both Mre11-S499P and Rad50-A78T reduce Tel1-MRX interaction leading to poor Tel1 association at DSBs and consequent loss of Tel1 activation. The Mre11-S499P variant reduces Mre11-Rad50 interaction, suggesting an important role for MR complex formation in Tel1 activation. Molecular dynamics simulations show that the wild type MR subcomplex bound to ATP lingers in a tightly 'closed' conformation, while ADP presence leads to the destabilization of Rad50 dimer and of Mre11-Rad50 association, both events being required for MR conformational transition to an open state. By contrast, MRA78T undertakes complex opening even if Rad50 is bound to ATP, indicating that defective Tel1 activation caused by MRA78T results from destabilization of the ATP-bound conformational state.

Authors+Show Affiliations

Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy.Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy.Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy.Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy.Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy.Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy.Dipartimento di Biotecnologie e Bioscienze, Università degli Studi di Milano - Bicocca, 20126 Milano, Italy.

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

30698745

Citation

Cassani, Corinne, et al. "The ATP-bound Conformation of the Mre11-Rad50 Complex Is Essential for Tel1/ATM Activation." Nucleic Acids Research, vol. 47, no. 7, 2019, pp. 3550-3567.
Cassani C, Vertemara J, Bassani M, et al. The ATP-bound conformation of the Mre11-Rad50 complex is essential for Tel1/ATM activation. Nucleic Acids Res. 2019;47(7):3550-3567.
Cassani, C., Vertemara, J., Bassani, M., Marsella, A., Tisi, R., Zampella, G., & Longhese, M. P. (2019). The ATP-bound conformation of the Mre11-Rad50 complex is essential for Tel1/ATM activation. Nucleic Acids Research, 47(7), 3550-3567. https://doi.org/10.1093/nar/gkz038
Cassani C, et al. The ATP-bound Conformation of the Mre11-Rad50 Complex Is Essential for Tel1/ATM Activation. Nucleic Acids Res. 2019 04 23;47(7):3550-3567. PubMed PMID: 30698745.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - The ATP-bound conformation of the Mre11-Rad50 complex is essential for Tel1/ATM activation. AU - Cassani,Corinne, AU - Vertemara,Jacopo, AU - Bassani,Matteo, AU - Marsella,Antonio, AU - Tisi,Renata, AU - Zampella,Giuseppe, AU - Longhese,Maria Pia, PY - 2019/01/15/accepted PY - 2018/12/17/revised PY - 2018/10/25/received PY - 2019/1/31/pubmed PY - 2019/10/11/medline PY - 2019/1/31/entrez SP - 3550 EP - 3567 JF - Nucleic acids research JO - Nucleic Acids Res VL - 47 IS - 7 N2 - Activation of the checkpoint protein Tel1 requires the Mre11-Rad50-Xrs2 (MRX) complex, which recruits Tel1 at DNA double-strand breaks (DSBs) through direct interaction between Tel1 and Xrs2. However, in vitro Tel1 activation by MRX requires ATP binding to Rad50, suggesting a role also for the MR subcomplex in Tel1 activation. Here we describe two separation-of-functions alleles, mre11-S499P and rad50-A78T, which we show to specifically affect Tel1 activation without impairing MRX functions in DSB repair. Both Mre11-S499P and Rad50-A78T reduce Tel1-MRX interaction leading to poor Tel1 association at DSBs and consequent loss of Tel1 activation. The Mre11-S499P variant reduces Mre11-Rad50 interaction, suggesting an important role for MR complex formation in Tel1 activation. Molecular dynamics simulations show that the wild type MR subcomplex bound to ATP lingers in a tightly 'closed' conformation, while ADP presence leads to the destabilization of Rad50 dimer and of Mre11-Rad50 association, both events being required for MR conformational transition to an open state. By contrast, MRA78T undertakes complex opening even if Rad50 is bound to ATP, indicating that defective Tel1 activation caused by MRA78T results from destabilization of the ATP-bound conformational state. SN - 1362-4962 UR - https://www.unboundmedicine.com/medline/citation/30698745/The_ATP_bound_conformation_of_the_Mre11_Rad50_complex_is_essential_for_Tel1/ATM_activation_ L2 - https://academic.oup.com/nar/article-lookup/doi/10.1093/nar/gkz038 DB - PRIME DP - Unbound Medicine ER -