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Biomedical subjects

Nadav Brandes

Publications and source records attributed to Nadav Brandes.

2 recordsLinked to original sources

Disruption of Polycystin Ciliary Localization and Channel Function by Autosomal Dominant Polycystic Kidney Disease-Causing Polycystin-1 Variants.

KEY POINTS: We developed assays to measure genetic variant effects on polycystin-1, the protein mutated in most autosomal dominant polycystic kidney disease. All tested pathogenic variants disrupted either polycystin-1 ciliary trafficking or channel function. Trafficking and channel function of some pathogenic variants was restored by low temperature culture to promote polycystin folding. BACKGROUND: Autosomal dominant polycystic kidney disease (ADPKD) is the leading monogenic cause of kidney failure and affects millions of people worldwide. Despite the prevalence of ADPKD, limited mechanistic understanding has hindered therapeutic development. Most ADPKD is caused by loss-of-function variants in polycystin-1 (PC1). METHODS: We developed assays that quantify the effect of nontruncating variants on PC1 ciliary localization, membrane trafficking, and polycystin channel function. RESULTS: We evaluated 29 nontruncating variants in PC1 and found that pathogenic variants disrupt two molecular phenotypes: ( 1 ) localization of PC1 at the primary cilium or ( 2 ) polycystin ion channel activity. Ciliary localization of a subset of polycystin variants was restored when cells were cultured at low temperature. A subset of variants with localization restored by low temperature formed functional channels. CONCLUSIONS: This study demonstrated that disruptions in polycystin ciliary trafficking and channel function are common causes of ADPKD. Defects in ciliary trafficking and channel function can be rescued for a subset of pathogenic variants, establishing a foundation for polycystin-targeted therapies in ADPKD.

Polycystic Kidney, Autosomal Dominant

Phenotypic pleiotropy of missense variants in human B cell confinement receptor P2RY8.

Missense variants can have pleiotropic effects on protein function, and predicting these effects can be difficult. We performed near-saturation deep mutational scanning of P2RY8, a G protein-coupled receptor that promotes germinal center B cell confinement. We assayed the effect of each variant on surface expression, migration, and proliferation. We delineated variants that affected both expression and function, affected function independently of expression, and discrepantly affected migration and proliferation. We also used cryo-electron microscopy to determine the structure of activated, ligand-bound P2RY8, providing structural insights into the effects of variants on ligand binding and signal transmission. We applied the deep mutational scanning results to both improve computational variant effect predictions and to characterize the phenotype of germline variants and lymphoma-associated variants. Together, our results demonstrate the power of integrating deep mutational scanning, structure determination, and in silico prediction to advance the understanding of a receptor important in human health.

Humans