SOCS-1 mimetics protect mice against lethal poxvirus infection: identification of a novel endogenous antiviral system.

The suppressor of cytokine signaling 1 (SOCS-1) protein modulates cytokine signaling by binding to and inhibiting the function of Janus kinases (JAKs), ErbB, and other tyrosine kinases. We have developed a small tyrosine kinase inhibitor peptide (Tkip) that binds to the autophosphorylation site of tyrosine kinases and inhibits activation of STAT transcription factors. We have also shown that a peptide corresponding to the kinase-inhibitory region of SOCS-1, SOCS1-KIR, similarly interacts with the activation loop of JAK2 and blocks STAT activation.