TonEBP Regulates PCNA Polyubiquitination in Response to DNA Damage through Interaction with SHPRH and USP1.

Hyun Je Kang,Jae Sun Ra,Kyoo-Young Lee,Kyungjae Myung,Whaseon Lee-Kwon,Jin-Hoe Hur,Jun Ho Lee,Soo Youn Choi,Eun-A Lee,Jeong Kon Seo,Hyug Moo Kwon,Hyun Park,Eun Jin Yoo

doi:10.1016/j.isci.2019.07.021

Abstract

SummaryPolyubiquitination of proliferating cell nuclear antigen (PCNA) regulates the error-free template-switching mechanism for the bypass of DNA lesions during DNA replication. PCNA polyubiquitination is critical for the maintenance of genomic integrity; however, the underlying mechanism is poorly understood. Here, we demonstrate that tonicity-responsive enhancer-binding protein (TonEBP) regulates PCNA polyubiquitination in response to DNA damage. TonEBP was recruited to DNA damage sites with bulky adducts and sequentially recruited E3 ubiquitin ligase SHPRH, followed by deubiquitinase USP1, to DNA damage sites, in correlation with the dynamics of PCNA polyubiquitination. Similarly, TonEBP was found to be required for replication fork protection in response to DNA damage. The Rel-homology domain of TonEBP, which encircles DNA, was essential for the interaction with SHPRH and USP1, PCNA polyubiquitination, and cell survival after DNA damage. The present findings suggest that TonEBP is an upstream regulator of PCNA polyubiquitination and of the DNA damage bypass pathway.

Highlights

DNA damage, such as bulky adducts, causes DNA polymerase stalling
proliferating cell nuclear antigen (PCNA) polyubiquitination in mammals is catalyzed by ubiquitin E3 ligases SHPRH and HLTF (Motegi et al, 2006, 2008; Unk et al, 2006, 2008), whereas PCNA deubiquitination is catalyzed by USP1 (Huang et al, 2006)
We identified 465 proteins that interacted with the N terminus of tonicity-responsive enhancer-binding protein (TonEBP) (Yc1), which encompasses the entire Rel-homology domain (RHD), including known DNA repair proteins SHPRH and USP1 (Figure 1C and Table S1)

Summary

Introduction

DNA damage tolerance mechanisms allow for a bypass of DNA lesions to suppress the collapse of the DNA replication fork (Berti and Vindigni, 2016). Error-prone translesion DNA polymerases replace replicative DNA polymerases in response to proliferating cell nuclear antigen (PCNA) monoubiquitination at the expense of the increased mutation rate (Berti and Vindigni, 2016; Kannouche and Lehmann, 2004). Template switching is initiated by polyubiquitination of PCNA and is an error-free pathway of DNA lesion bypass mediated by an uncharacterized mechanism. PCNA polyubiquitination facilitates filling of postreplicative single-stranded DNA (ssDNA) gaps via template switching and recombinational mechanisms involving sister chromatid junctions (Berti and Vindigni, 2016; Giannattasio et al, 2014). An alternative model of error-free bypass and template switching entails remodeling of the replication fork in a four-way junction, a process known as replication fork reversal, to enable template switching to occur directly in the elongating fork (Higgins et al, 1976)

Methods

Results

Discussion

Conclusion