Liquid–Liquid Phase Separation: Mechanisms, Roles, and Implications in Cellular Function and Disease

Liquid-liquid phase separation is a basic biophysical process that creates essential membraneless organelles that support different cellular activities, including chromatin organization and gene expression. The malfunction of liquid-liquid phase separation (LLPS) plays a critical role in numerous diseases, such as neurodegenerative disorders, including amyotrophic lateral sclerosis (ALS) and Alzheimer's disease (AD), which involve TDP-43 and Tau, various cancers that utilize SPOP and YAP/TAZ proteins, and viral infections where pathogens use LLPS to replicate and avoid immune detection. This review brings together the fast-growing knowledge about LLPS across multiple scientific fields. The paper examines the physiological functions of LLPS along with its disease pathogenesis mechanisms and presents various experimental techniques (e.g., advanced microscopy, FRAP, FCS) for its investigation. It introduces new therapeutic approaches such as PTM modulation, small molecules like 1,6-hexanediol and Lipoamide, and advanced genetic tools including CRISPR and PROTACs like PSETAC, which also explores diagnostic applications. The thorough integration of knowledge presented here is essential to connect separate scientific findings while propelling research forward and turning LLPS discoveries into new biomedical developments.