Biology subjects

Voss, S.

Publications and source records attributed to Voss, S..

6 recordsLinked to original sources

bioRxiv2026

Reprogramming VHL with molecular glues enables selective degradation of caspase-2

Molecular glue degraders (MGDs) reprogram E3 ligases to eliminate neosubstrates, yet their application has largely been confined to CRBN. Here, we identify caspase-2 as a new neosubstrate for von Hippel-Lindau (VHL), expanding the scope of VHL-based MGDs. Guided by a focused VHL ligand library design, we employed TurboID-based proximity labeling to discover stereoisomeric compounds (dCASP2-1 and dCASP2-2) that selectively recruit caspase-2 to VHL and promote its ubiquitin-proteasome system-dependent degradation. Further structure-activity relationship (SAR) studies yielded dCASP2-3 and dCASP2-4, which enhanced degradation potency (by 622-fold relative to dCASP2-1) and abolished enantioselectivity. Mechanistic mapping localized the degrader-induced interface to a two-helix region of the caspase-2 CARD domain, with residues H33, P34, and D100 essential for VHL engagement. Degron-guided computational modeling of the VHL/MGD/caspase-2 ternary complex provided structural insight into neosubstrate recognition. Together, we report the development of VHL molecular glues that selectively and potently degrade caspase-2, offering chemical probes to interrogate its functions in apoptosis and stress responses, while broadening the substrate landscape of VHL-based MGDs.

biochemistry↗

bioRxiv2026

The DES-p.A120P mutation associated with biventricular arrhythmogenic cardiomyopathy has a dominant-negative effect on desmin filament assembly

Desmin is a muscle-specific intermediate filament protein, which connects different cell organelles and is highly relevant for the structural integrity of cardiomyocytes. Mutations in the DES gene, cause different cardiomyopathies including arrhythmogenic cardiomyopathy. In this study, we functionally investigate the novel genetic variant DES-p.A120P using cell transfection experiments including cardiomyocytes derived from induced pluripotent stem cells in combination with confocal microscopy. These experiments reveal that the filament assembly of desmin-p.A120P is disturbed - even when co-expressed with wild-type desmin. In conclusion, the functional characterization of desmin-p.A120P supports the classification as a pathogenic variant associated with arrhythmogenic cardiomyopathy.

genetics↗

bioRxiv2025

Discovery of a VHL molecular glue degrader of GEMIN3 by Picowell RNA-seq

Targeted protein degradation (TPD) is an emerging therapeutic modality in which small molecules are used to recruit targets to the natural protein degradation machinery of the cell. Molecular glue degraders (MGD) are monovalent small molecules that accomplish this by redirecting E3 ubiquitin ligases to target proteins, offering the potential to degrade previously unliganded and "undruggable" proteins in cancer, neurodegenerative, and other diseases. While attractive due to their drug-like properties, MGDs are exceptionally hard to discover and have largely been identified serendipitously. The Von Hippel-Lindau (VHL) E3 ligase is the second most widely used effector for TPD, though current VHL-based degraders are primarily large heterobifunctional PROTACs (proteolysis-targeting chimeras) designed using target-based ligands. Here, we have instead pursued target-agnostic discovery of VHL MGDs leveraging proprietary ultra-miniaturized microfluidics devices (Picowells) to facilitate unbiased RNA-seq screening of a biased E3-focused library. This resulted in dGEM3, a novel VHL molecular glue that targets the survival of motor neuron (SMN) complex member GEMIN3 for degradation. Through a combination of cellular, biochemical, and biophysical assays, we have characterized the GEMIN3 degron within its helicase ATP-binding domain, and how the kinetics of ternary complex formation impact degradation. These findings provide insights on the re-programmability of VHL for novel targets using drug-like molecular glues.

biochemistry↗

bioRxiv2023

Atlas of DES (desmin) variants: Impact of variants located within the head domain on filament assembly

Desmin is a muscle-specific intermediate filament protein, which plays a significant role in providing structural integrity of cardiomyocytes by connecting different cell organelles and multi-protein complexes. DES mutations cause cardiomyopathies and skeletal myopathies. Most of these pathogenic mutations are localized in the highly conserved rod domain and affect the filament assembly. However, the impact of DES variants within the N-terminal head domain on the filament assembly process is widely unknown. Therefore, we inserted a set of 85 different head domain variants with unknown significance from human genetic databases in expression constructs and investigated their impact on filament formation in cell culture in combination with confocal microscopy. The majority of these desmin variants do not affect the filament assembly. However, the desmin variants -p.S13P, -p.N107D, -p.E108G and -p.K109E significantly inhibit the filament assembly. Additionally, we expressed and purified recombinant desmin and investigated the filament assembly defects by atomic force microscopy verifying these findings at the single molecular level. Furthermore, we truncated systematically the head domain to investigate which general parts of this domain are necessary for filament assembly. In summary, our functional investigations might be relevant for the classification of novel DES variants and the genetic counselling of patients carrying desmin head variants.

cell biology↗

bioRxiv2021

Cyp26b1 restrains murine heart valve growth during development

Endothelial cells (ECs) are critical to proper heart valve development, directly contributing to the mesenchyme of the cardiac cushions, which progressively transform into mature valves. To date, investigators have lacked useful markers of valve ECs to fully evaluate their contributions during valve morphogenesis. As a result, it has been unclear whether the well-characterized regional differentiation of valves correlates with any endothelial domains in the heart. Furthermore, it has been difficult to ascertain whether endothelial heterogeneity in the heart influences underlying mesenchymal zones in an angiocrine manner. To identify regionally expressed EC genes in the heart valves, we screened publicly available databases and assembled a toolkit of endothelial-enriched genes. We identified Cyp26b1 as one of many endothelial enriched genes found to be expressed in the endocardium of the developing cushions and valves. Here, we show that Cyp26b1 is required for normal heart valve development. Genetic ablation of Cyp26b1 in mouse embryos leads to abnormally thickened aortic valve leaflets, which is due in part to increased endothelial and mesenchymal cell proliferation in the remodeling valves. In addition, Cyp26b1 mutant hearts display ventricular septal defects (VSDs) in a portion of null embryos. We show that loss of Cyp26b1 results in upregulation of retinoic acid (RA) target genes, supporting the observation that Cyp26b1 has RA-dependent roles. Together, this work identifies a novel role for Cyp26b1 in heart valve morphogenesis. Understanding the spatiotemporal expression dynamics of cardiac EC genes will likely prove useful to the investigation of both normal as well as dysfunctional heart valve development. HIGHLIGHTS{middle dot} A mouse heart valve gene expression atlas can be generated with publicly available online tools, such as Genepaint and other gene expression databases. {middle dot} Endothelium of developing mouse heart valves is regionally heterogeneous. {middle dot} Cyp26b1 is expressed in the endocardial/endothelial lining of developing heart valves. {middle dot} Loss of Cyp26b1 leads to significant enlargement of aortic valves and to ventricular septal defects. {middle dot} Cyp26b1 represses cell proliferation in valve mesenchyme. {middle dot} Retinoic acid targets are upregulated in Cyp26b1-/- heart valves, indicating dysregulation of RA metabolism.

developmental biology↗

bioRxiv2019

Electroporated recombinant proteins as tools for in vivo functional complementation, imaging, and chemical biology

Delivery of native or chemically modified recombinant proteins into mammalian cells shows promise for functional investigations and various technological applications, but concerns that sub-cellular localization and functional integrity of delivered proteins may be affected remain high. Here, we surveyed batch electroporation as a delivery tool for single polypeptides and multi-subunit protein assemblies of kinetochores, a spatially confined and well-studied subcellular structures. After electroporation in human cells, recombinant fluorescent Ndc80 and Mis12 multi-subunit complexes displayed native localization, physically interacted with endogenous binding partners, and functionally complemented depleted endogenous counterparts to promote mitotic checkpoint signaling and chromosome segregation. Farnesylation is required for kinetochore localization of the Dynein adaptor Spindly. In cells with chronically inhibited farnesyl transferase activity, in vitro farnesylation and electroporation reconstituted robust kinetochore localization of Spindly. Thus, electroporation is uniquely versatile for delivering synthetic and, as required, chemically modified functional mimics of endogenous proteins, and is therefore a promising tool for chemical and synthetic biology.

cell biology↗