The purpose of this experiment was to characterize the network of proteins that interact with TIA1, and to investigate whether tau exerts control over TIA1 protein interactions, TIA1 was immunoprecipitated from cortical brain tissue of 10 month-old WT (C57BL/6J), tau-/- and TIA1-/- mice. The specificity of the TIA1 IP was verified by immunoblotting with anti-TIA1 antibody (Fig. 3A), and the resulting TIA1 proteome was examined by mass spectrometry.