Novel insight into the composition of human single-stranded DNA-binding protein 1 (hSSB1)-containing protein complexes

Abstract

BackgroundSingle-stranded DNA-binding proteins are essential cellular components required for the protection, metabolism and processing of single-stranded DNA. Human single-stranded DNA-binding protein 1 (hSSB1) is one such protein, with described roles in genome stability maintenance and transcriptional regulation. As yet, however, the mechanisms through which hSSB1 functions and the binding partners with which it interacts remain poorly understood.ResultsIn this work, hSSB1 was immunoprecipitated from cell lysate samples that had been enriched for non-soluble nuclear proteins and those associating with hSSB1 identified by mass spectrometry. In doing so, 334 potential hSSB1-associating proteins were identified, with known roles in a range of distinct biological processes. Unexpectedly, whilst hSSB1 has largely been studied in a genome stability context, few other DNA repair or replication proteins were detected. By contrast, a large number of proteins were identified with roles in mRNA metabolism, reflecting a currently emerging area of hSSB1 study. In addition, numerous proteins were detected that comprise various chromatin-remodelling complexes.ConclusionsThese findings provide new insight into the binding partners of hSSB1 and will likely function as a platform for future research.Electronic supplementary materialThe online version of this article (doi:10.1186/s12867-016-0077-5) contains supplementary material, which is available to authorized users.

Biochemical characterization of INTS3 and C9ORF80, two subunits of hNABP1/2 heterotrimeric complex in nucleic acid binding

“…Recently, the Richard laboratory found that hNABP2 is associated with a large number of proteins with roles in mRNA metabolism and various chromatin-remodeling complexes [ 33 ]. Similarly, our co-IP experiment also revealed many transcription-related proteins associate with hNABP2, indicating its potential role in transcriptional regulation (Supplementary Figure S9 and Table S5).…”

OB-Folds and Genome Maintenance: Targeting Protein–DNA Interactions for Cancer Therapy

“…hSSB1 and hSSB2 can each interact with an integrator complex subunit 3 (INTS3) and C90ORF80 to form trimeric SS binding complexes termed SOSS1/2 (sensors of single stranded DNA) complexes [79] (Figure 4). In addition to complexation with the INTS3 and C9orf80, hSSB1 forms protein-protein interactions with NBS1, a component of the MRE11-RAD50-NBS1 (MRN) repair complex that was recently shown to be regulated by SUMOylation [80,81]. Depletion of hSSB1 inhibited MRN recruitment to sites of DSB and diminishes MRN nuclease activity.…”

Divergent Roles of RPA Homologs of the Model Archaeon Halobacterium salinarum in Survival of DNA Damage

“…In addition to their role in coating and protecting lagging strand DNA, they are necessary for protection of single-stranded regions generated during other processes, including restarting stalled replication forks, homologous recombination, and DNA repair [ 1 , 2 , 3 , 4 ]. During these processes, SSB/RPA proteins recruit and interact with a variety of other cellular proteins, and their interactions change depending on the state of the DNA [ 1 , 4 , 5 , 6 ]. Through these interactions, SSB/RPAs orchestrate the process being carried out [ 1 , 2 , 4 , 5 , 6 ].…”

“…During these processes, SSB/RPA proteins recruit and interact with a variety of other cellular proteins, and their interactions change depending on the state of the DNA [ 1 , 4 , 5 , 6 ]. Through these interactions, SSB/RPAs orchestrate the process being carried out [ 1 , 2 , 4 , 5 , 6 ]. SSBs/RPAs are characterized by containing one or more ssDNA binding domains, oligonucleotide oligosaccharide-binding (OB) fold domains, and are thought to have originated from duplication of an ancestral SSB gene [ 7 , 8 ].…”