(A) Representation of the caspase substrate-binding pocket. Four subsites on the caspase (Subsite 4 to Subsite 1) recognise the classical tetrapeptide on the substrate (P4 to P1). (B) Structure of the complex between caspase-11 (pink and cyan) and Gasdermin D (PDB: 6VIE) demonstrates that caspases can use exosite to recognise specific substrates. The structure shows the tetrapeptide recognise by the substrate-binding pocket (green) and the exosite (blue) that binds an additional region on Gasdermin D.