The Ebolavirus VP24 protein blocks phosphorylation of p38 mitogen-activated protein kinase

Type I interferon (IFN) signaling is mediated through several signaling pathways, including the Janus kinase and signal transducer and activator (JAK-STAT) and p38 mitogen-activated protein (MAP) kinase pathways. The VP24 protein of Ebolavirus is an IFN antagonist, blocking type I IFN signaling through the JAK-STAT pathway. Here, we show that, in 293 cells, VP24 also interferes with the p38 MAP kinase pathway by blocking IFN-b–stimulated phosphorylation of p38-a. Similar inhibition was not observed in HeLa cells, suggesting cell type–specific differences in signal transduction. The interferon (IFN) response is the first line of defense against viral infections. Type I IFN (IFN-a and IFN-b) execute their antiviral activities via signal transduction pathways, resulting in the transcriptional upregulation of hundreds of genes whose products inhibit various stages of virus replication [1, 2]. Although the Janus kinase and signal transducer and activator (JAK-STAT) pathway is the best-characterized type I IFN–induced signal transduction pathway