The severe acute respiratory syndrome coronavirus (SARS-CoV) generates 16 nonstructural proteins (nsp's) through proteolytic cleavage of a large precursor protein. Although several nsp's exhibit catalytic activities that are important for viral replication and transcription, other nsp's have less clearly defined roles during an infection. In order to gain a better understanding of their functions, we attempted to identify host proteins that interact with nsp's during SARS-CoV infections. For nsp2, we identified an interaction with two host proteins, prohibitin 1 (PHB1) and PHB2. Our results suggest that nsp2 may be involved in the disruption of intracellular host signaling during SARS-CoV infections.