CLARP, a death effector domain-containing protein interacts with caspase-8 and regulates apoptosis

Proc Natl Acad Sci U S A. 1997 Sep 30;94(20):10717-22. doi: 10.1073/pnas.94.20.10717.

Abstract

We have identified and characterized CLARP, a caspase-like apoptosis-regulatory protein. Sequence analysis revealed that human CLARP contains two amino-terminal death effector domains fused to a carboxyl-terminal caspase-like domain. The structure and amino acid sequence of CLARP resemble those of caspase-8, caspase-10, and DCP2, a Drosophila melanogaster protein identified in this study. Unlike caspase-8, caspase-10, and DCP2, however, two important residues predicted to be involved in catalysis were lost in the caspase-like domain of CLARP. Analysis with fluorogenic substrates for caspase activity confirmed that CLARP is catalytically inactive. CLARP was found to interact with caspase-8 but not with FADD/MORT-1, an upstream death effector domain-containing protein of the Fas and tumor necrosis factor receptor 1 signaling pathway. Expression of CLARP induced apoptosis, which was blocked by the viral caspase inhibitor p35, dominant negative mutant caspase-8, and the synthetic caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-(OMe)-fluoromethylketone (zVAD-fmk). Moreover, CLARP augmented the killing ability of caspase-8 and FADD/MORT-1 in mammalian cells. The human clarp gene maps to 2q33. Thus, CLARP represents a regulator of the upstream caspase-8, which may play a role in apoptosis during tissue development and homeostasis.

Publication types

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

MeSH terms

  • Adaptor Proteins, Signal Transducing*
  • Amino Acid Sequence
  • Apoptosis*
  • Arabidopsis Proteins*
  • CASP8 and FADD-Like Apoptosis Regulating Protein
  • Carrier Proteins / metabolism
  • Caspase 1
  • Catalysis
  • Cloning, Molecular
  • Cysteine Endopeptidases / metabolism*
  • DNA, Complementary
  • Fas-Associated Death Domain Protein
  • Fatty Acid Desaturases / metabolism
  • Humans
  • Intracellular Signaling Peptides and Proteins*
  • Molecular Sequence Data
  • Plant Proteins / metabolism
  • Protein Binding
  • Proteins / chemistry
  • Proteins / genetics
  • Proteins / metabolism*
  • Receptors, Tumor Necrosis Factor / metabolism
  • Receptors, Tumor Necrosis Factor, Member 25
  • Sequence Homology, Amino Acid
  • Signal Transduction
  • Tumor Cells, Cultured
  • fas Receptor / metabolism

Substances

  • Adaptor Proteins, Signal Transducing
  • Arabidopsis Proteins
  • CASP8 and FADD-Like Apoptosis Regulating Protein
  • CFLAR protein, human
  • Carrier Proteins
  • DNA, Complementary
  • FADD protein, human
  • Fas-Associated Death Domain Protein
  • Intracellular Signaling Peptides and Proteins
  • Plant Proteins
  • Proteins
  • Receptors, Tumor Necrosis Factor
  • Receptors, Tumor Necrosis Factor, Member 25
  • TNFRSF25 protein, human
  • fas Receptor
  • Fatty Acid Desaturases
  • Fad7 protein, Arabidopsis
  • Cysteine Endopeptidases
  • Caspase 1

Associated data

  • GENBANK/AF005774
  • GENBANK/AF005775
  • GENBANK/AF031652