Protein kinase Cθ:: a new essential superstar on the T-cell stage

Recent studies have identified protein kinase C theta (PKC theta), a member of the Ca2+-independent PKC family as an essential component of the T-cell synapse that cooperates with calcineurin to activate the interleukin-2 (IL-2) gene. Several selective functions of PKC theta involved in the activation and survival of T cells are reviewed herein. Among these, the nuclear factor-kappaB (NF-kappaB) signaling cascade appears to be the most critical target of PKC theta in the T-cell receptor/CD28 costimulatory pathway that leads to T-cell activation.