Cytokines are secreted proteins that regulate diverse biological functions by binding to
receptors at the cell surface to activate complex signal transduction pathways including the
Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway. Stringent
mechanisms of signal attenuation are essential for ensuring an appropriate, controlled
cellular response. Three families of proteins, the SH2-containing phosphatases (SHP), the
protein inhibitors of activated STATs (PIAS), and the suppressors of cytokine signaling …