Abstract
Aberrant biomolecular condensates are implicated in multiple incurable neurological disorders, including Amyotrophic Lateral Sclerosis (ALS), Frontotemporal Dementia (FTD), and DYT1 dystonia. However, the role of condensates in driving disease etiology remains poorly understood. Here, we identify myeloid leukemia factor 2 (MLF2) as a disease-agnostic biomarker for phase transitions, including stress granules and nuclear condensates associated with dystonia. Exploiting fluorophore-derivatized MLF2 constructs, we developed a high-content platform and computational pipeline to screen modulators of NE condensates across chemical and genetic space. We identified RNF26 and ZNF335 as protective factors that prevent the buildup of nuclear condensates sequestering K48-linked polyubiquitinated proteins. Chemical screening identified four FDA-approved drugs that potently modulate condensates by resolving polyubiquitinated cargo and MLF2 accumulation. Our exploratory integrated chemical-genetics approach suggests that modulation of zinc, and potentially autophagy and oxidative stress, is critical for condensate modulation and nuclear proteostasis, offering potential therapeutic strategies for neurological disorders. Application of our platform to a genome-wide CRISPR KO screen identified strong enrichment of candidate genes linked to primary microcephaly and related neurodevelopmental disorders. Two hypomorphic microcephaly-associated alleles of ZNF335 failed to rescue nuclear condensate accumulation in ZNF335 KO cells, suggesting that aberrant condensates and impaired nuclear proteostasis may contribute to the pathogenesis of microcephaly. HIGHLIGHTS: MLF2 emerges as a disease-agnostic condensate biomarker co-localizing with TDP-43 and G3BP1FDA-approved drugs target condensates linked to perturbed proteostasis.RNF26 and ZNF335 are identified as modulators of nuclear phase transitions.Microcephaly patient disease alleles fail to counteract aberrant condensates.