Dataset Information

USP3 counteracts RNF168 via deubiquitinating H2A and ?H2AX at lysine 13 and 15.

ABSTRACT: Histone ubiquitination plays a vital role in DNA damage response (DDR), which is important for maintaining genomic integrity in eukaryotic cells. In DDR, ubiquitination of histone H2A and ?H2AX by the concerted action of ubiquitin (Ub) ligases, RNF168 and RNF8, generates a cascade of ubiquitination signaling. However, little is known about deubiquitinating enzymes (DUBs) that may catalyze the removal of Ub from these histones. This study demonstrated that USP3, an apparent DUB for mono-ubiquitinated H2A, is indeed the enzyme for deubiquitinating Ub conjugates of ?H2AX and H2A from lysine sites, where the ubiquitination is initiated by RNF168. Here, we showed that ectopic expression of USP3 led to the deubiquitination of both H2A and ?H2AX in response to UV-induced DNA damage. Moreover, ectopic USP3 expression abrogated FK2 antibody-reactive Ub-conjugate foci, which co-localize with damage-induced ?H2AX foci. In addition, USP3 overexpression impaired the accumulation of downstream repair factors BRCA1 and 53BP1 at the damage sites in response to both UV and ?-irradiation. We further identified that the USP3 removes Ub at lysine 13 and 15 of H2A and ?H2AX, as well as lysine 118 and 119 of H2AX in response to DNA damage. Taken together, the results suggested that USP3 is a negative regulator of ubiquitination signaling, counteracting RNF168- and RNF8-mediated ubiquitination.

SUBMITTER: Sharma N

PROVIDER: S-EPMC3925719 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature

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USP3 counteracts RNF168 via deubiquitinating H2A and γH2AX at lysine 13 and 15.

Sharma Nidhi N Zhu Qianzheng Q Wani Gulzar G He Jingshan J Wang Qi-en QE Wani Altaf A AA

Cell cycle (Georgetown, Tex.) 20131024 1

Histone ubiquitination plays a vital role in DNA damage response (DDR), which is important for maintaining genomic integrity in eukaryotic cells. In DDR, ubiquitination of histone H2A and γH2AX by the concerted action of ubiquitin (Ub) ligases, RNF168 and RNF8, generates a cascade of ubiquitination signaling. However, little is known about deubiquitinating enzymes (DUBs) that may catalyze the removal of Ub from these histones. This study demonstrated that USP3, an apparent DUB for mono-ubiquitin ...[more]

PMID: 24196443

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Project description:BackgroundModulation of chromatin structure has emerged as a critical molecular device to control gene expression. Histones undergo different post-translational modifications that increase chromatin accessibility to a number of regulatory factors. Among them, histone ubiquitination appears relevant in nuclear processes that govern gene silencing, either by inhibiting or activating transcription, and maintain genome stability, acting as scaffold to properly organize the DNA damage response. Thus, it is of paramount importance the identification and the characterization of new ubiquitin ligases that address histones.ResultsWe identified and characterized RNF168, a new chromatin-associated RING finger protein. We demonstrated that RNF168 is endowed with ubiquitin ligase activity both in vitro and in vivo, which targets histones H2A and H2AX, but not H2B, forming K63 polyubiquitin chains. We previously described the presence within RNF168 sequence of two MIU domains, responsible for the binding to ubiquitinated proteins. Here we showed that inactivation of the MIUs impairs ubiquitin binding ability in vitro and reduces chromatin association of RNF168 in vivo. Moreover, upon formation of DNA double strand breaks induced by chemical and physical agents, RNF168 is recruited to the DNA damage foci, where it co-localizes with gammaH2AX and 53BP1. The localization of RNF168 at the site of damage highly increases the local concentration of ubiquitinated proteins and determines the prolonged ubiquitination signal.ConclusionThe RING finger protein RNF168 is a new ubiquitin ligase that functions as chromatin modifier, through histone ubiquitination. We hypothesize a dual function for RNF168. In normal condition RNF168 modifies chromatin structure by modulating ubiquitination of histone H2A. Upon DNA lesions, RNF168 is recruited to DNA damage response foci where it contributes to increase the amount of ubiquitinated proteins, thereby facilitating the downstream signalling cascade.

Dataset Information

USP3 counteracts RNF168 via deubiquitinating H2A and ?H2AX at lysine 13 and 15.

Publications

USP3 counteracts RNF168 via deubiquitinating H2A and γH2AX at lysine 13 and 15.

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