Biomolecular condensates: molecular structure, biological functions, diseases, and therapeutic targets.

Cells constantly encounter environmental and physiological fluctuations that challenge homeostasis and threaten viability. In response to these cues, specific proteins and nucleic acids engage in multivalent interactions and undergo phase separation to form membraneless assemblies known as biomolecular condensates. Nuclear condensates include paraspeckles, nuclear speckles, and Cajal bodies, while cytoplasmic condensates include stress granules, processing bodies, RNA transport granules, U-bodies, and Balbiani bodies. These assemblies regulate transcription, splicing fidelity, RNA stability, translational reprogramming, and integration of signaling pathways, thereby serving as dynamic platforms for metabolic regulation and physiological adaptation. However, dysregulation of these condensates has been increasingly recognized as a central pathogenic mechanism in neurodegenerative diseases, cancers, and viral infections, contributing to toxic protein aggregation, nucleic acid dysregulation, and aberrant cell survival signaling. This review provides a comprehensive synthesis of the molecular mechanisms governing condensation, delineates the diverse types and functions of major biomolecular condensates, and examines therapeutic approaches based on their pathophysiological relevance to disease development and progression. Furthermore, we highlight the cutting-edge technologies, including CRISPR/Cas-based imaging, optogenetic manipulation, and AI-driven phase separation prediction tools, which enable the real-time monitoring and precision targeting of cytoplasmic biomolecular condensates. These insights underscore the emerging potential of biomolecular condensates as both biomarkers and therapeutic targets, paving the way for precision medicine approaches in condensate-associated diseases.