Programmed cell death in the filamentous fungus Schizophyllum commune

Study of metacaspases in organisms as diverse as Arabadopsis and yeast has provided evidence for the existence of a form of cell death in these organisms. Metacaspases have a His‐Cys diad similar to that found in caspases, and several have been shown to autoprocess into subunits similar to the p20 and p10 subunits in animal caspases. However, the metacaspases cleave proteins after basic residues rather than after aspartic acid as in the animal caspases. Our work focuses on the five metacaspes in the recently‐sequenced genome of the filamentous fungus Schizophyllum commune . Two metacaspase ORFs (scp1 and scp2) have long prodomains, while three ORFs (scp3, scp4 and scp5) do not, suggestive of initiator and executioner caspases. The S. commune genome also codes for a homolog of Tudor staphylococcal nuclease, a protein that has been shown to be a metacaspase substrate in plants and is similar to an animal caspase substrate. Further analysis of the S. commune genome suggests that it is a good model organism for studying the components of cell death in fungi.