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Jeroen A A Demmers

Publications and source records attributed to Jeroen A A Demmers.

2 recordsLinked to original sources
PubMed2026

Proteome-wide Ubiquitinome Profiling Reveals Substrate-specific Dynamics Within the USP7 Network.

USP7 is a pleiotropic deubiquitylating enzyme that is involved in tumor suppression, (neuro) development, chromatin regulation and the DNA damage response. How USP7 regulates these diverse pathways is still unclear. Here, we report data-independent acquisition and label free quantitation mass spectrometry to profile the proteome-wide impact of USP7 on substrate de-ubiquitylation and overall protein abundance. First, we identified proteins associated with endogenous USP7 by immunopurification followed by data-independent acquisition and label free quantitation mass spectrometry. Integration of our new results with earlier interactomes of epitope-tagged USP7 yielded a consensus set of high-confidence protein targets. Domain mapping analysis revealed that, in addition to the TRAF domain, the ubiquitin-like domains of USP7 play a key role in substrate selection. Using specific enrichment of tryptic K-ε-GG peptides, we mapped proteome-wide changes in ubiquitinome dynamics following inhibition of USP7. Combining unbiased proteome-wide and targeted quantitative mass spectrometry revealed that deubiquitylation by USP7 can have different effects on the stability of distinct substrates, and suggests that USP7's activity profile is substrate-dependent rather than an intrinsic enzymatic property. Thus, in addition to providing a proteome-wide map of USP7 target sites, our multi-angle proteomics approach reveals that the effects of USP7-mediated deubiquitylation on its targets are remarkably variable and substrate-specific. Finally, based on these detailed molecular insights we show how USP7 connects various neurodevelopmental syndromes and tumor suppression pathways.

Ubiquitin-Specific Peptidase 7↗
PubMed2026

Phosphoproteomic Analysis of Cortical Tissue from Mice Lacking Both CaMKIIα and CaMKIIβ Identifies Novel In Vivo Substrates.

Ca2+/calmodulin-dependent protein kinase II (CaMKII) plays a critical role in calcium signaling. Several studies have shown that mice with single Camk2a or Camk2b gene knockouts are viable, yet exhibit distinct phenotypes, whereas the double knockout of both genes is lethal. These findings indicate that each gene can have distinct roles and that they also partially compensate for each other in yet unknown essential brain functions. In order to provide insight into potential novel CaMKII functions, we performed parallel phosphoproteomic analyses on nonstimulated cortex tissues from inducible Camk2a and Camk2b double knockout (Camk2af/f;Camk2bf/f;CAG-CreESR) mice and from wild type mice. A total of 5622 phosphorylated peptides derived from 2080 proteins were identified. Phosphorylation at serine/threonine residues in 130 proteins was downregulated in the double knockout mice, including residues in 113 proteins that have not previously been identified as potential CaMKII substrates. Comparison of amino acid sequences surrounding the downregulated phosphorylation residues provided new insights into the CaMKII-substrate consensus sequences in vivo. This data set provides an important resource for future studies examining novel roles for CaMKII in the brain.

Animals↗