Nuclear Accumulation of LAP1:TRF2 Complex during DNA Damage Response Uncovers a Novel Role for LAP1

Abstract

Lamina-associated polypeptide 1 (LAP1) is a nuclear envelope (NE) protein whose function remains poorly characterized. In a recent LAP1 protein interactome study, a putative regulatory role in the DNA damage response (DDR) has emerged and telomeric repeat-binding factor 2 (TRF2), a protein intimately associated with this signaling pathway, was among the list of LAP1 interactors. To gain insights into LAP1′s physiological properties, the interaction with TRF2 in human cells exposed to DNA-damaging agents was investigated. The direct LAP1:TRF2 binding was validated in vitro by blot overlay and in vivo by co-immunoprecipitation after hydrogen peroxide and bleomycin treatments. The regulation of this protein interaction by LAP1 phosphorylation was demonstrated by co-immunoprecipitation and mass spectrometry following okadaic acid exposure. The involvement of LAP1 and TRF2 in the DDR was confirmed by their increased nuclear protein levels after bleomycin treatment, evaluated by immunoblotting, as well as by their co-localization with DDR factors at the NE and within the nucleoplasm, assessed by immunocytochemistry. Effectively, we showed that the LAP1:TRF2 complex is established during a cellular response against DNA damage. This work proposes a novel functional role for LAP1 in the DDR, revealing a potential biological mechanism that may be disrupted in LAP1-associated pathologies.

Fourier-Transform Infrared Spectroscopy as a Discriminatory Tool for Myotonic Dystrophy Type 1 Metabolism: A Pilot Study

“…For FTIR spectroscopy analysis, a fibroblasts density of 0.9 × 10 6 was used. Briefly, primary fibroblasts were cultured and after reaching around 90% of confluency (T75 flasks), the fibroblasts were PBS washed, trypsinazed using 0.05% trypsin-EDTA (Gibco solution and then resuspended in 3 mL of fresh complete medium and cell density determined as previously described [ 31 , 32 ]. A total of 0.9 × 10 6 fibroblasts were used for each replicate.…”

Nuclear Envelope Integrity in Health and Disease: Consequences on Genome Instability and Inflammation

“…The relationship between DNA damage response and NE is complex, and it is known that several NE proteins play important functions during DNA damage repair, such as the proteins from the LINC complex [ 122 , 123 ] or the Lamin-Associated Protein 1 (LAP1) [ 124 ]. Then, the disruption of NE integrity also compromises the proper DNA repair.…”

The Intra- and Extra-Telomeric Role of TRF2 in the DNA Damage Response

“…Another study had found that TRF2 transiently formed a complex with laminaassociated polypeptide 1 (LAP1) upon DNA break induction and the complex was recruited at the DNA damage site [141]. Further investigation is needed in order to address the mechanism of TRF2 recruitment to the DSB site and to explore the function of TRF2 in the repair of non-telomeric DNA DSB.…”