ABSTRACT Many diseases, including cancer and those resulting from viral infections, are associated with alterations in the function of host translational machinery. These alterations are referred to as “ribosomal hijacking” and occur through various mechanisms. I propose to explore a poorly characterized mechanism utilized by pathogenic mRNAs. This mechanism involves the inhibition of canonical host proteins involved in translation and results in the activation of a non-canonical translation pathway mediated by the alternate translation initiation factor eIF2A, a distinct protein from the canonical eIF2 complex. Under stress conditions, phosphorylation of the alpha-subunit of eIF2 results in general downregulation of cellular protein synthesis. Yet, mRNAs that contain internal ribosome entry sites (IRES), such as hepatitis C virus (HCV) and proto-oncogene tyrosine-protein kinase Src (c-Src), circumvent eIF2-mediated translation initiation through an eIF2A-mediated alternate mechanism. The role of eIF2A in translation of these mRNAs underscores its significance as this mechanism exhibits a significant connection to human health and disease. Exploring the biochemical and structural basis for eIF2A binding and recruitment of tRNA to form an initiation complex with the ribosome will increase our understanding of eIF2A function and the role it plays in the translation of pathogenic mRNA. To elucidate the mechanism of eIF2A-mediated initiation I will determine high resolution structures of eIF2A loading tRNA onto the ribosome in an initiation state via cryoEM. Furthermore, I will employ crystallography techniques to determine high resolution structures of eIF2A-tRNA complexes to determine the basis for tRNA binding and selectivity by eIF2A.