TIA1 is a cytotoxic granule-associated RNA binding protein that functions primarily as a regulator of stress granule (SG) assembly and RNA metabolism 1. As a core SG component, TIA1 binds RNA through its low-complexity domain and regulates alternative mRNA splicing and translational control, particularly of transcripts containing U-rich elements 2. Under stress conditions, TIA1 promotes phase separation and SG formation, which can stabilize or sequester specific mRNAs from degradation 2. Pathogenic TIA1 mutations in the low-complexity domain are associated with amyotrophic lateral sclerosis (ALS) with or without frontotemporal dementia 1. These mutations enhance phase separation propensity, delay stress granule disassembly, and promote TDP-43 accumulation in SGs, contributing to neurodegeneration 1. In ALS models, elevated TIA1 mediates SG formation that sequesters heat shock protein 70 (HSP70) mRNA, impairing protein quality control and exacerbating disease 3. Additionally, TIA1 variants cause Welander distal myopathy, either alone or through digenic inheritance with SQSTM1 polymorphisms 4. Beyond neurodegeneration, TIA1 regulates cellular stress responses including mitochondrial dynamics and senescence through miR-30-5p-mediated expression changes 5. TIA1 also interacts with SARS-CoV-2 RNA elements, suggesting roles in viral regulation 6.