TIA1 or Tia1 cytotoxic granule-associated rna binding protein is a 3UTR mRNA binding protein that can bind the 5TOP sequence of 5'TOP mRNAs.  It is associated with programmed cell death (apoptosis) and regulates alternative splicing of the gene encoding the Fas receptor, an apoptosis-promoting protein. Under stress conditions, TIA1 localizes to cellular RNA-protein conglomerations called stress granules. It is encoded by the TIA1 gene.
Mutations in the TIA1 gene have been associated with amyotrophic lateral sclerosis, frontotemporal dementia, and Welander distal myopathy. It also plays a crucial role in the development of toxic oligomeric tau in Alzheimer's disease.