Phosphorylation of the Archaeal Holliday Junction Resolvase Hjc Inhibits Its Catalytic Activity and Facilitates DNA Repair in Sulfolobus islandicus REY15A.

Qihong Huang,Guihua Hou,Yulong Shen,Chao Zhang,Qing Zhong,Jinfeng Ni,Joseph Badys Mayaka

doi:10.3389/fmicb.2019.01214

Qihong Huang, Guihua Hou + Show 5 more

Open Access

https://doi.org/10.3389/fmicb.2019.01214

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Journal: Frontiers in microbiology	Publication Date: May 31, 2019
Citations: 9	License type: CC BY 4.0

Affiliation: Shandong University

Abstract

Protein phosphorylation is one of the main protein post-translational modifications and regulates DNA repair in eukaryotes. Archaeal genomes encode eukaryotic-like DNA repair proteins and protein kinases (ePKs), and several proteins involved in homologous recombination repair (HRR) including Hjc, a conserved Holliday junction (HJ) resolvase in Archaea, undergo phosphorylation, indicating that phosphorylation plays important roles in HRR. Herein, we performed phosphorylation analysis of Hjc by various ePKs from Sulfolobus islandicus. It was shown that SiRe_0171, SiRe_2030, and SiRe_2056, were able to phosphorylate Hjc in vitro. These ePKs phosphorylated Hjc at different Ser/Thr residues: SiRe_0171 on S34, SiRe_2030 on both S9 and T138, and SiRe_2056 on T138. The HJ cleavage activity of the phosphorylation-mimic mutants was analyzed and the results showed that the cleavage activity of S34E was completely lost and that of S9E had greatly reduced. S. islandicus strain expressing S34E in replacement of the wild type Hjc was resistant to higher doses of DNA damaging agents. Furthermore, SiRe_0171 deletion mutant exhibited higher sensitivity to DNA damaging agents, suggesting that Hjc phosphorylation by SiRe_0171 enhanced the DNA repair capability. Our results revealed that HJ resolvase is regulated by protein phosphorylation, reminiscent of the regulation of eukaryotic HJ resolvases GEN1 and Yen1.

Highlights

DNA repair is the fundamental processes of life and is interwined with other processes such as DNA replication, recombination, and clustered regularly interspaced short palindromic repeats (CRISPR)-Cas immunity in prokaryotes (Jones and Petermann, 2012; Faure et al, 2019)
Proteins participating genetic information processing in archaea have served as structural models for understanding the mechanisms of DNA metabolism, Abbreviations: BER, base excision repair; CRISPR, clustered regularly interspaced short palindromic repeats; DDR, DNA damage response; DSB, double-strand break; ePK, eukaryotic-like protein kinase; Holliday junction (HJ), holliday junction; HRR, homologous recombination repair; KD, protein kinase catalytic domain; MMR, mismatch repair; NHEJ, non-homology end joining; PTM, post-translational modification; Rio, right open reading frame
It was reported that the HJ resolvase Hjc, but not Hje, and several other DSBs repair proteins Rad50, NurA, and Hjm were phosphorylated in a phosphatase deletion mutant of S. acidocaldarius (Reimann et al, 2013)

Summary

Introduction

DNA repair is the fundamental processes of life and is interwined with other processes such as DNA replication, recombination, and CRISPR-Cas immunity in prokaryotes (Jones and Petermann, 2012; Faure et al, 2019). Early stage of HRR in archaea relies on Mre and Rad which are eukaryoticlike; while, further processing to generate 3 ssDNA overhang depends on the archaea-specific helicase/nuclease complex HerANurA (White, 2011). As another example, archaea lack the canonical bacterial and eukaryotic MutS-MutL MMR pathway, but they harbor a novel non-canonical protein EndoMS for mismatch recognition and repair (Ishino et al, 2016, 2018; Castaneda-Garcia et al, 2017)

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