Biology subjects

Lopez-Mosqueda, J.

Publications and source records attributed to Lopez-Mosqueda, J..

3 recordsLinked to original sources

bioRxiv2026

PARP1-mediated PARylation of SPRTN restrains its DNA-protein crosslink repair activity

SPRTN is a DNA-dependent metalloprotease that resolves DNA-protein crosslinks, but how its activity is restrained on chromatin remains unclear. Here we show that SPRTN is PARylated in a PARP1- and HPF1-dependent manner. Mass spectrometry datasets identify seven modified residues in the C-terminal region, and substituting them (SPRTN-PARless) strongly reduces PARylation. The Nudix homology domain is required for SPRTN to interact with PARP1 and for efficient PARylation. SPRTN-PARless accumulates faster and to higher levels at laser-induced DNA damage than wild-type SPRTN. PARylation reduces single-stranded DNA binding of both cell-derived and purified SPRTN, and PARG treatment reverses this effect for cell-derived protein. SPRTN-PARless shows increased autocleavage and accelerates clearance of camptotheci-induced TOP1 cleavage complexes. These findings suggest that PARylation acts as negative feedback on SPRTN after its PAR-dependent recruitment, restraining its DNA engagement and proteolytic activity.

molecular biology↗

bioRxiv2026

PARP1 recruits SPRTN to DNA-protein crosslinks through a conserved poly-ADP-ribose binding domain.

DNA-protein crosslinks (DPCs) are toxic DNA lesions formed by the covalent attachment of proteins to DNA. Failure to resolve DPCs leads to genomic instability, premature aging, and cancer predisposition. Although multiple proteases and the 26S proteasome degrade DPCs, how these lesions are detected and marked for proteolysis remains unclear. Here, we show that poly-(ADP-ribose) polymerases (PARP1/2) sense DPCs and modify them with poly(ADP-ribose) (PAR) to promote repair via a SPRTN-Tdp1 axis. We discovered a Nudix homology domain (NHD) in SPRTN that mediates direct non-covalent PAR binding and is important for DPC repair. Loss of PARP1/2 activity or mutation of the SPRTN NHD leads to sustained DPCs. Single-molecule analysis revealed that SPRTN does not bind efficiently to the DPC, however after the addition of PARP1 in the presence of NAD+, SPRTN binding to the DPC was significantly increased. Our findings establish PARP1/2 enzymes as immediate DPC sensors, reveal PARylation as a signal marking DPCs for SPRTN-dependent degradation, and identify SPRTN as the first PARP-directed protease.

molecular biology↗

bioRxiv2019

Wss1 promotes replication stress tolerance by degrading histones.

Timely completion of DNA replication is central to accurate cell division and to the maintenance of genomic stability. However, certain DNA-protein interactions can physically impede DNA replication fork progression. Cells remove or bypass these physical impediments by different mechanisms to preserve DNA macromolecule integrity and genome stability. In Saccharomyces cerevisiae, Wss1, the DNA-protein crosslink repair protease, allows cells to tolerate hydroxyurea-induced replication stress but the underlying mechanism by which Wss1 promotes this function has remained unknown. Here we report that Wss1 provides cells tolerance to replication stress by directly degrading core histone subunits that non-specifically and non-covalently bind to single-stranded DNA. Unlike Wss1-dependent proteolysis of covalent DNA-protein crosslinks, proteolysis of histones does not require Cdc48 nor SUMO-binding activities. Wss1 thus acts as a multi-functional protease capable of targeting a broad range of covalent and non-covalent DNA-binding proteins to preserve genome stability during adverse conditions.

cell biology↗