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

Recent studies have identified protein kinase Cθ (PKCθ), 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 PKCθ involved in the activation and survival of T cells are reviewed herein. Among these, the nuclear factor-≃B (NF-≃B) signaling cascade appears to be the most critical target of PKCθ in the T-cell receptor/CD28 costimulatory pathway that leads to T-cell activation.