Biology subjects

Xirodimas, D.

Publications and source records attributed to Xirodimas, D..

3 recordsLinked to original sources

bioRxiv2023

Targeting the deNEDDylating enzyme NEDP1 to ameliorate ALS phenotypes through Stress Granules dissolution

In Amyotrophic Lateral Sclerosis (ALS) motor neuron disease, mutations in proteins that upon stress localize within cytoplasmic protein inclusions called Stress Granules (SGs), are linked to the formation of aberrant inclusions, which are related to neuronal cell death. By combining studies in human cells and C. elegans including the use of Nanobodies, we found that inhibition of NEDP1, the enzyme responsible for the processing and deconjugation of the Ubiquitin-like molecule NEDD8 from substrates, promotes the elimination both of physiological and pathological SGs. The hyper-NEDDylation of Poly-(ADP-ribose) polymerase-1 enzyme upon NEDP1 inhibition compromises PAR production and is a key mechanism for the observed SG phenotype. Importantly, the above-described effects are related to improved cell survival in human cells, and in C. elegans, NEDP1 deletion ameliorates ALS-phenotypes related to animal motility. Our studies reveal NEDP1 as potential therapeutic target for ALS, based on the elimination of aberrant SGs.

cell biology↗

bioRxiv2020

Development of Nanobodies as first-in-class inhibitors for the NEDP1 deNEDDylating enzyme

Protein NEDDylation emerges as an important post-translational modification and an attractive target for therapeutic intervention. Modification of NEDD8 onto substrates is finely balanced by the co-ordinated activity of conjugating and deconjugating enzymes. The NEDP1/DEN1/SENP8 protease is a NEDD8 specific processing and deconjugating enzyme that regulates the NEDDylation mainly of non-cullin substrates. Here, we report the development and characterisation of nanobodies as first-in-class inhibitors for NEDP1. The nanobodies display high-affinity (low nM) against NEDP1 and specifically inhibit NEDP1 processing activity in vitro and NEDP1 deconjugating activity in tissue-culture cells and in cell extracts. We also isolated nanobodies that bind to NEDP1 with high-affinity but do not affect NEDP1 activity. The developed nanobodies provide new tools to study the function of NEDP1 and to prevent deNEDDylation in cell extracts used in biochemical assays.

molecular biology↗

bioRxiv2019

The NEDD8 cycle controlled by NEDP1 upon DNA damage is a regulatory module of the HSP70 ATPase activity

Ubiquitin and ubiquitin-like chains are finely balanced by the action of conjugating and de-conjugating enzymes. Alterations in this balance trigger signalling events required for the response to stress conditions and are often observed in pathologies. How such changes are detected is not well-understood. We show that upon DNA damage the induction of the de-NEDDylating enzyme NEDP1 restricts the formation of poly-NEDD8 chains, mainly through lysines K11/K48. This promotes APAF1 oligomerisation and apoptosis induction, a step that requires the HSP70 ATPase activity. We found that HSP70 binds to NEDD8 and in vitro, mono-NEDD8 stimulates the ATPase activity of HSP70, counteracted upon poly-NEDDylation. This effect is independent of NEDD8 conjugation onto substrates. The studies identify the HSP70 chaperone as sensor of changes in the NEDD8 cycle, providing mechanistic insights for a cytoplasmic role of NEDD8 in the DNA damage induced apoptosis. They also indicate that the balance between mono- versus poly-NEDDylation is a regulatory module of HSP70 function. The above findings may be important in tumorigenesis, as we find that NEDP1 levels are downregulated in Hepatocellular Carcinoma with concomitant accumulation of NEDD8 conjugates.

molecular biology↗