Endogenous inhibitors of caspases

J Clin Immunol. 1999 Nov;19(6):388-98. doi: 10.1023/a:1020502800208.


Caspases are cysteine proteases that are specific for aspastic acid residues. These enzymes have been extensively characterized as integral and highly conserved components of a variety of cell death programs. Cowpox and several insect viruses have evolved mechanisms that counter host cell suicide by encoding proteins that directly inhibit caspases-thereby allowing propagation of viral progeny within the host cell. It has only recently been elucidated, however, that endogenous cellular inhibitors of the caspases exist. To date five members of the inhibitor of apoptosis (IAP) family of proteins has been identified in humans and at least three of these have been shown directly to inhibit specific caspases. Thus, members of the IAP family of proteins are the only endogenous inhibitors of caspases known in mammals. Here we discuss the caspase and IAP families of proteins and review the data concerning their relationship.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Animals
  • Apoptosis*
  • Caspase Inhibitors*
  • Caspases / physiology
  • Cysteine Proteinase Inhibitors / physiology*
  • Humans
  • Inhibitor of Apoptosis Proteins
  • Proteins / physiology*
  • Signal Transduction
  • Viral Proteins / physiology*
  • X-Linked Inhibitor of Apoptosis Protein


  • Caspase Inhibitors
  • Cysteine Proteinase Inhibitors
  • Inhibitor of Apoptosis Proteins
  • Proteins
  • Viral Proteins
  • X-Linked Inhibitor of Apoptosis Protein
  • XIAP protein, human
  • inhibitor of apoptosis, Nucleopolyhedrovirus
  • Caspases