Biology subjects

Beckmann, L.

Publications and source records attributed to Beckmann, L..

4 recordsLinked to original sources

bioRxiv2025

Computational design and experimental characterization of mini-protein binders targeting Nipah, Langya and Measles virus receptor-binding domains

A lack of reagents represents a major bottleneck in pandemic preparedness and rapid vaccine development. It is therefore important to enable the design of reagents for use in the treatment and diagnosis of emerging viral diseases. Ideally, the design and identification platform is fast, can be performed by testing only a small number of candidates and enables a generally applicable strategy. In this study, we assessed the ability of recently developed computational protein design tools to establish such a workflow for validating paramyxovirus receptor-binding protein de novo binders as such reagents. The family Paramyxoviridae includes various members that cause severe disease and exhibit re-occurring zoonotic spillover events, with documented human infections over the past decades. We successfully designed, identified, and characterized mini-proteins targeting the receptor binding proteins of Nipah virus, Langya virus, and Measles virus while screening as few as 10-16 designs per target. The resulting functional binders have moderate to low nanomolar affinities and display high on-target specificity. We further showed that our most promising Nipah virus receptor-binding protein binder is able to inhibit human receptor binding in vitro and competes for an epitope that overlaps with that of the neutralizing antibody HENV-117. However, despite these promising results, this Nipah binder is only weakly neutralizing, preventing therapeutic applications. Nevertheless, we established a platform, applicable to rapidly generate diagnostically relevant proteins from only a small number of candidates, and developed novel reagents for the Paramyxoviridae family.

bioinformatics↗

bioRxiv2023

A predicted amphipathic helix contributes to the efficient S-acylation of the Arabidopsis thaliana Calcineurin B-like protein 2

Membrane targeting of the Calcineurin B-like (CBL) calcium sensor proteins through protein S-acylation is crucial for various processes in plants, like nutrient uptake, plant development, and response to abiotic and biotic stresses. Certain CBLs target specifically to the vacuolar membrane, but which factors contribute to this particular localization and to the lipid modification efficiency are not yet known. Here, we examined the structural features of the N-terminus of Arabidopsis thaliana CBL2 and show that the lipid-modified cysteines are integrated within a predicted amphipathic helix. Mutations of amino acids, which contribute to the formation of this specific domain, affect S-acylation efficiency, membrane binding and function of CBL2. Interestingly, overexpression of the protein S-acyl transferase (PAT) 10 can compensate for the binding deficiency of a CBL2 mutant variant, which harbours a helix breaker mutation. This indicates that helix formation is rather involved in the S-acylation mechanism and is less important for membrane binding. Moreover, the introduction of basic residues resulted in a partial shift of the protein from the vacuolar to the plasma membrane, indicating that the underrepresentation of positively charged amino acids contributes to the vacuolar targeting specificity. Overall, our data suggest that helix formation is potentially an initial step in the S-acylation process and provides a deeper understanding of the mechanistic interplay between PATs and tonoplast targeted CBLs.

plant biology↗

bioRxiv2022

Differential roles of neural crest- and endothelial-derived FOXC2 in trabecular meshwork and Schlemms Canal in glaucomatous pathology

Impaired development and maintenance of the Schlemms Canal (SC) is associated with perturbed aqueous humor outflow regulation and glaucoma progression. Key molecular mechanisms, such as ANGPT/TIE2, PROX1, and VEGF-C/VEGFR-3 regulate SC development and maintenance, but mechanisms of paracrine signaling from neighboring tissues, including the trabecular meshwork (TM) are poorly understood. Here, we show Foxc2 is critical within the neural crest (NC)-derived TM and SC endothelium for development of the aqueous humor outflow pathway. In mice, NC- specific deletion of Foxc2 results in abnormal anterior eye segment development, including impaired SC morphogenesis and functional maintenance, loss of SC identity, and impaired maintenance of intraocular pressure (IOP). Visible light optical coherence tomography angiography analysis also demonstrated functional impairment of the SC in response to changes in IOP in NC-Foxc2-/- mice, suggesting increased TM stiffness. Utilization of single-cell RNA-sequencing (scRNA-seq) analysis then identified that this phenotype is predominately characterized by transcriptional changes associated with extracellular matrix organization and stiffness in TM-associated cell clusters, including increased matrix metalloproteinase (MMP) expression, which can generate soluble TIE2 that acts as an ANGPT trap. As FOXC2 is also critically involved in development of the lymphatic vasculature in other tissues, we also show that endothelial-specific deletion of Foxc2 resulted in impaired SC morphogenesis due to loss of TIE2 expression, which was rescued by deletion of the TIE2 phosphatase VE-PTP. Thus, NC-Foxc2 is critical for development of the TM, and both NC- and endothelial-Foxc2 are key for maintenance of SC identity and its morphogenesis.

developmental biology↗

bioRxiv2021

Adaptive spectroscopic visible-light optical coherence tomography for human retinal oximetry

Alterations in the retinal oxygen saturation (sO2) and oxygen consumption are associated with nearly all blinding diseases. A technology that can accurately measure retinal sO2 has the potential to improve ophthalmology care significantly. Recently, visible-light optical coherence tomography (vis-OCT) showed great promise for noninvasive, depth-resolved measurement of retinal sO2 as well as ultra-high resolution anatomical imaging. We discovered that spectral contaminants (SC), if not correctly removed, could lead to incorrect vis-OCT sO2 measurements. There are two main types of SCs associated with vis-OCT systems and eye conditions, respectively. Their negative influence on sO2 accuracy is amplified in human eyes due to stringent laser power requirements, eye motions, and varying eye anatomies. We developed an adaptive spectroscopic vis-OCT (Ads-vis-OCT) method to iteratively remove both types of SCs. We validated Ads-vis-OCT in ex vivo bovine blood samples against a blood-gas analyzer. We further validated Ads-vis-OCT in 125 unique retinal vessels from 18 healthy subjects against pulse-oximeter readings, setting the stage for clinical adoption of vis-OCT.

bioengineering↗