The goal of these studies is to understand the possible role of viral proteins in the induction of cellular cytotoxicity in human lung epithelial cells. Two proteins were identified which appear to track to mitochondria and to cause mitochondrial toxicity by ultrastructural analysis. One protein causes cytochrome C release into the cytoplasma and mitochondrial apoptosis. The other appears to cause mitochondrial autophagy. Studies are ongoing to define protein interactions and pathways by which these changes may occur.