Reactive oxygen species induce Cys106-mediated anti-parallel HMGB1 dimerization that protects against DNA damage
Man Sup Kwak,
Woo Joong Rhee,
Yong Joon Lee,
Hee Sue Kim,
Young Hun Kim,
Min Kyung Kwon,
Jeon-Soo Shin
Affiliations
Man Sup Kwak
Department of Microbiology, Yonsei University College of Medicine, Seoul, 03722, South Korea; Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, 03722, South Korea
Woo Joong Rhee
Department of Microbiology, Yonsei University College of Medicine, Seoul, 03722, South Korea
Yong Joon Lee
Department of Microbiology, Yonsei University College of Medicine, Seoul, 03722, South Korea; Brain Korea 21 FOUR Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, South Korea
Hee Sue Kim
Department of Microbiology, Yonsei University College of Medicine, Seoul, 03722, South Korea; Brain Korea 21 FOUR Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, South Korea
Young Hun Kim
Department of Microbiology, Yonsei University College of Medicine, Seoul, 03722, South Korea; Brain Korea 21 FOUR Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, South Korea
Min Kyung Kwon
Department of Microbiology, Yonsei University College of Medicine, Seoul, 03722, South Korea
Jeon-Soo Shin
Department of Microbiology, Yonsei University College of Medicine, Seoul, 03722, South Korea; Institute for Immunology and Immunological Diseases, Yonsei University College of Medicine, Seoul, 03722, South Korea; Brain Korea 21 FOUR Project for Medical Science, Yonsei University College of Medicine, Seoul, 03722, South Korea; Severance Biomedical Science Institute, Yonsei University College of Medicine, Seoul, 03722, South Korea; Institute of Basic Science, Yonsei University, Seoul, 03722, South Korea; Corresponding author. Department of Microbiology, Yonsei University College of Medicine, 50-1 Yonsei-ro Seodaemun-gu, Seoul, 03722, South Korea.
Oxidative stress can induce covalent disulfide bond formation between protein-protein thiol groups and generate hydroxyl free radicals that damage DNA. HMGB1 is a DNA chaperone and damage-associated molecular pattern molecule. As a redox-sensitive protein, HMGB1 contains three cysteine residues: Cys23, Cys45, and Cys106. In this study, we focused on the relationship between HMGB1 dimerization and DNA stabilization under oxidative stress conditions. HMGB1 dimerization was positively modulated by CuCl2 and H2O2. Mutation of the Cys106 residue blocked dimer formation. Treatment of HEK293T cells with CuCl2 and H2O2 enhanced the oxidative self-dimerization of HMGB1, whereas this dimerization was inhibited in mutant HMGB1C106A cells. Furthermore, we performed a bimolecular fluorescence complementation assay to visualize Cys106 oxidation-induced HMGB1 dimerization in live cells exposed to oxidative stress and were able to reproduce the dimerization effect of HMGB1 in fluorescence resonance energy transfer analysis. Interestingly, dimerized HMGB1 bound to DNA with higher affinity than monomeric HMGB1. Dimerized HMGB1 protected DNA from damage due to hydroxyl free radicals and prevented cell death. In conclusion, dimerized HMGB1 may play a regulatory role in DNA stabilization under oxidative stress.
