Aug 2026· International Journal of Molecular Sciences· Vol 27, pp. 7054· 0 citations· 54 references
Medicine
TL;DR
This study identified the yeast ortholog of WDR45 and established a Saccharomyces cerevisiae-based functional complementation assay to assess the pathogenicity of WDR45 variants, establishing a simple, robust, and scalable yeast model that enables functional interpretation of WDR45 variants and improves molecular diagnosis of BPAN.
Abstract
β-propeller protein-associated neurodegeneration (BPAN) is the most prevalent subtype of neurodegeneration with brain iron accumulation (NBIA) and is caused by mutations in the WDR45 gene encoding the autophagy-related protein WIPI4. However, many WDR45 missense variants remain classified as variants of uncertain significance (VUS), highlighting the need for reliable functional assays to support their clinical interpretation. In this study, we identified the yeast ortholog of WDR45 and established a Saccharomyces cerevisiae-based functional complementation assay to assess the pathogenicity of WDR45 variants. We first showed that deletion of the β-propellers that bind polyphosphoinositides (PROPPIN)-encoding genes ATG18 or HSV2 causes mitochondrial dysfunction and impaired respiratory growth. Human WDR45/WIPI4 specifically rescued the respiratory defect of the atg18Δ strain, whereas WDR45B/WIPI3 complemented the hsv2Δ phenotype, establishing yeast Atg18 as the closest functional counterpart of WIPI4, thus clarifying PROPPIN orthology. We then evaluated a panel of WDR45 variants and found that benign variants restored normal growth, whereas truncating and pathogenic missense variants failed to complement the atg18Δ phenotype, validating the assay for functional variant classification. Finally, we analyzed several VUS identified in patients with clinically compatible BPAN and obtained functional evidence supporting their pathogenicity. Overall, our study establishes a simple, robust, and scalable yeast model that enables functional interpretation of WDR45 variants and improves molecular diagnosis of BPAN.
A primary mechanism of SLC26A4 regulation in the inner ear and kidney and of SLC26A4 loss of function in Pendred syndrome and deafness DFNB4 is described and a atomistic model of the complete SLC26A4/ZBTB16/Cullin 3/RocI complex is provided in agreement with experimental results.
Florian Huber, E. Bernardinelli, Bassam G. Haddad et al.· Journal of Biomedical Scienc...· 0 citations
This study represents the first application of a Drosophila model to demonstrate that KCNK3 functions as a dosage-sensitive regulator of neurodevelopment and position KCNK3 as a candidate gene for molecular screening and pave the way for future functional studies and therapeutic exploration in NDDs.
Functional analysis in stable H9c2 cardiomyoblast cell lines demonstrated significantly reduced MFN2 mutant protein expression, extensive mitochondrial clustering and fragmentation, suggesting a significant correlation with the pathogenesis of DCM.
M. Gupta, A. Mukhopadhyay, M. Yadav et al.· medRxiv· 0 citations
Pathogenic variants in RUBCN, encoding the Run domain Beclin-1 interacting and cysteine-rich domain-containing protein (Rubicon) have been implicated in autosomal recessive spinocerebellar ataxia 15 (SCAR15). However, the molecular mechanisms underlying disease pathogenesis remain poorly understood. Here, we report 18 individuals from 15 unrelated families harbouring biallelic RUBCN variants, who present with an aggressive neurodevelopmental disorder variably characterized by seizures, developmental delay, intellectual disability and movement abnormalities that cause regression, progressive brain atrophy and neurodegenerative features. Through functional characterization, we demonstrate that a subset of disease-associated putative truncating variants disrupt autophagy regulation. In Caenorhabditis elegans models, loss-of-function RUBCN variants result in an increased autophagic flux and impaired neuronal function, recapitulating key features in humans. Correspondingly, cellular assays reveal that nonsense and frameshift RUBCN variants lead to defective autophagy inhibition, underscoring a crucial role for RUBCN as a key negative autophagy regulator. Molecular dynamics simulations rank the eleven missense variants by structural effect, with p.Arg813Trp alone altering the target protein at both the local and the regional level and lying within the RAB7A-binding module that the truncating alleles remove altogether. Our findings establish and expand the RUBCN-related disorders as a clinically and molecularly distinct subset of autophagy-related diseases. By delineating both the genetic landscape and cellular consequences of Rubicon dysfunction, this study enhances our understanding of autophagy-related neurodevelopmental disorders and provides a foundation for future therapeutic investigations.
S. Efthymiou, K. Tabata, H. Dafsari et al.· medRxiv· 0 citations
These findings establish a mechanistic link between mutation-induced structural dynamics and impaired PINK1–ubiquitin recognition at Ser65, providing a mutation-specific framework for understanding early mitophagy impairment in ARPD and supporting future molecular assessment and targeted therapeutic development.
Zhiguang Jia, B. Malik, Deborah Vincent et al.· Frontiers in Molecular Neuro...· 0 citations
The findings implicate DCLK1 in a previously unrecognized progressive neurodevelopmental disorder and demonstrate the power of integrative cross-species functional genomics in resolving ultra-rare disease variants.
Stephen C. Pak, David Butler, Wei-Xi Yuan et al.· Research Square· 0 citations
We use cookies to run the site and, with your consent, for analytics and to show ads.
See our Cookie Policy.
