ABSTRACT
The Type I interferons are a group of related glycoproteins that play a key role in
host defenses against viral infections. The interferons bind to a cell surface receptor
and initiate the transcription of a wide range of proteins that have potent antiviral
properties. The mechanism by which interferon binding to the cell surface initiates
gene transcription has recently been elucidated and involves activation of protein
kinases (JAK 1 and Tyk 2) followed by phosphorylation and activation of transcriptional
regulators (the STATproteins). These signal transduction molecules are not unique
to the interferon signaling pathway, and other cytokines as diverse as erythropoietin
and IL-2 use the same, or related proteins. To overcome the antiviral effects of the
type I interferons, some viruses that cause chronic infections have developed interferon
inhibitors that reduce the effectiveness of endogenous and exogenous interferon.
KEY WORDS
signal transduction - antiviral - JAK - STAT
