I have studied bacterial DNA replication in my PhD (2011-2013) and assistant professor period (2013-2017) at Prof. Tsutomu Katayama group in Kyushu University, Japan, to address the regulatory mechanism of the initiator protein DnaA. In these periods, I identified new regulatory pathways for DnaA: an inactivation pathway DDAH (2013 PNAS; 2017 JBC) and an activation pathway DARS2 stimulated by two nucleoid proteins IHF and Fis (2014 NAR; 2019 NAR). Also, I am interested in cell cycle-dependent oscillation and genome-wide regulation of IHF-DNA binding to reveal the mechanism of timely initiation of DNA replication. Then I moved to Dr Sjoerd Wanrooij group in Umeå University, Sweden and worked as a postdoc (2017-2021) to start studying human mitochondrial DNA (mtDNA) maintenance. I have also been employed as a JSPS Overseas Fellow to study the cell cycle-coordinated regulation of mtDNA replication (2018-2019). During this period, I focused on the stimulatory mechanism of PrimPol DNA polymerase by its interacting partner PolDIP2). Interestingly, I revealed that PolDIP2 has a specific arginine cluster to stabilize dNTP-binding of PrimPol to increase DNA synthesis (2021 NAR). Furthermore, I collaborated with Prof. Ludmilla A. Morozova-Roche and identified a novel regulatory mechanism for inhibiting amyloid tau aggregation by PolDIP2 (IJMS, in press). Now, I came back to Kyushu University, Japan, to continue and develop all my bacterial, mitochondrial, and amyloidal projects.