The crucial role of single-stranded DNA binding in enhancing sensitivity to DNA-damaging agents for Schlafen 11 and Schlafen 13

Kohei Fujiwara; Masashi Maekawa; Yuki Iimori; Akane Ogawa; Takeshi Urano; Nobuaki Kono; Hiroyuki Takeda; Shigeki Higashiyama; Makoto Arita; Junko Murai

doi:10.1016/j.isci.2023.108529

The crucial role of single-stranded DNA binding in enhancing sensitivity to DNA-damaging agents for Schlafen 11 and Schlafen 13

iScience. 2023 Nov 23;26(12):108529. doi: 10.1016/j.isci.2023.108529. eCollection 2023 Dec 15.

Authors

Kohei Fujiwara^{1

2

3}, Masashi Maekawa¹, Yuki Iimori², Akane Ogawa², Takeshi Urano^{4

5}, Nobuaki Kono^{2

6}, Hiroyuki Takeda⁷, Shigeki Higashiyama^{8

9

10}, Makoto Arita^{1

3

11

12}, Junko Murai^{2

8

9}

Affiliations

¹ Division of Physiological Chemistry and Metabolism, Graduate School of Pharmaceutical Sciences, Keio University, Minato-Ku, Tokyo 105-8512, Japan.
² Institute for Advanced Biosciences, Keio University, Tsuruoka, Yamagata 997-0052, Japan.
³ Laboratory for Metabolomics, RIKEN Center for Integrative Medical Sciences, Yokohama, Kanagawa 230-0045, Japan.
⁴ Department of Biochemistry, Faculty of Medicine, Shimane University, Izumo, Shimane 693-8501, Japan.
⁵ Center for Vaccines and Therapeutic Antibodies for Emerging Infectious Diseases, Shimane University, Izumo, Shimane 693-8501, Japan.
⁶ Systems Biology Program, Graduate School of Media and Governance, Keio University, Fujisawa, Kanagawa 252-0882, Japan.
⁷ Division of Proteo-Drug-Discovery, Proteo-Science Center, Ehime University, Matsuyama, Ehime 790-8577, Japan.
⁸ Division of Cell Growth and Tumor Regulation, Proteo-Science Center, Ehime University, Toon, Ehime 791-0295, Japan.
⁹ Department of Biochemistry and Molecular Genetics, Ehime University Graduate School of Medicine, Toon, Ehime 791-0295, Japan.
¹⁰ Department of Oncogenesis and Tumor Regulation, Osaka International Cancer Institute, Chuo-Ku, Osaka 541-8567, Japan.
¹¹ Human Biology-Microbiome-Quantum Research Center (WPI-Bio2Q), Keio University, Tokyo, Japan.
¹² Cellular and Molecular Epigenetics Laboratory, Graduate School of Medical Life Science, Yokohama City University, Yokohama, Kanagawa 230-0045, Japan.

Abstract

Schlafen (SLFN) 11 enhances cellular sensitivity to various DNA-damaging anticancer agents. Among the human SLFNs (SLFN5/11/12/13/14), SLFN11 is unique in its drug sensitivity and ability to block replication under DNA damage. In biochemical analysis, SLFN11 binds single-stranded DNA (ssDNA), and this binding is enhanced by the dephosphorylation of SLFN11. In this study, human cell-based assays demonstrated that a point mutation at the ssDNA-binding site of SLFN11 or a constitutive phosphorylation mutant abolished SLFN11-dependent drug sensitivity. Additionally, we discovered that nuclear SLFN13 with a point mutation mimicking the DNA-binding site of SLFN11 was recruited to chromatin, blocked replication, and enhanced drug sensitivity. Through generating multiple mutants and structure analyses of SLFN11 and SLFN13, we identified protein phosphatase 2A as a binding partner of SLFN11 and the putative binding motif in SLFN11. These findings provide crucial insights into the unique characteristics of SLFN11, contributing to a better understanding of its mechanisms.

Keywords: Biochemistry; Drugs; Molecular biology.