(1) The carboxyl terminus of TIAR contains a lysosome-targeting motif, indicating that TIAR is probably a cytotoxic granule-associated protein.
(2) Although immunoblotting analysis of post-nuclear supernatants revealed TIA-1 protein to be restricted to CTLs, PCR analysis revealed the expression of TIA-1 and TIAR mRNA transcripts in a wide variety of cell types.
(3) Here we report the characterization of a cDNA encoding a TIA-1-related protein designated TIAR.
(4) The deduced amino acid sequence of TIAR reveals it to be a 42-kDa protein possessing three RNA-binding domains and a carboxyl-terminal auxiliary domain.
(5) Although the RNA-binding domains of TIA-1 and TIAR share greater than 85% amino acid homology, their carboxyl-terminal auxiliary domains are only 51% homologous.
(6) Like TIA-1, purified recombinant TIAR induced DNA fragmentation in permeabilized target cells.