T cell intracellular antigen-1 (TIA1), an apoptosis-promoting factor, is an RNA-binding protein (RBP) that associates with subsets of mRNAs bearing U-rich sequences in their 3′-untranslated regions (UTRs) and shuttles between the nucleus and cytoplasm. TIA1 possesses 3 RNA-recognition motifs (RRMs). RRM2 and the first half of the auxiliary region are necessary for nuclear accumulation, while RRM3 mediates nuclear export. TIA1 regulates the splicing of alternatively spliced pre-mRNAs, including those of Fas, msl-2, FGFR-2, calsitonin/CGRP, in the nucleus. In the cytoplasm, TIA1 regulates the translation of various mRNAs, including those of TNF-, Cox-2, HMMP-13, and 2-adrenergic receptor, by binding to the AU-rich elements (AREs) located in the 3′-UTRs of these mRNAs. In addition to playing a role in translational silencing, TIA1 is also involved in the cellular responses to environmental stresses by promoting the assembly of a noncanonical 48S preinitiation complex that is the core component of cytoplasmic stress granules (SG). Like other mRNA-turnover and translation regulators, such as AUF-1, HuR, KSRP, and NF90, TIA1 also associates with its cognate mRNA and the transcripts of other RBPs