IL-18

By Victoria Osinski, PhD

By Stephanie Melchor

Cell death via apoptosis is a key cellular function triggered by the cell death receptor family and their ligands. This regulated process then transmits downstream signals through adaptor molecules ending with the caspase cysteine proteases. Caspase 11 has a heterotetrameric structure consisting of two anti-parallel heterodimers. Upon activation, it is cleaved by an autocatalytic mechanism to give rise to individual subunits. This post-translational regulation enables rapid activation. Expression levels of caspase 11 are highest in lung and spleen.

The nuclear factor kappa B (NFkB) is a ubiquitous transcription factor essential for the activation of immune and inflammatory responses. NFkB activity is inhibited when it is associated with IkB proteins in the cell cytoplasm. IkB proteins are phosphorylated by the IkB kinase complex. The IKK serine protein kinase consists of alpha and beta subunits (IKK alpha and IKK beta). These subunits interact with each other and together, are essential for NFkB activation. IKK alpha is expressed in variety of human tissues.