Drosophila grim induces apoptosis in mammalian cells.
Genetic studies have shown that grim is a central genetic switch of programmed cell death in Drosophila; however, homologous genes have not been described in other species, nor has its mechanism of action been defined. We show here that grim expression induces apoptosis in mouse fibroblasts. Cell death induced by grim in mammalian cells involves membrane blebbing, cytoplasmic loss and nuclear DNA fragmentation. Grim-induced apoptosis is blocked by both natural and synthetic caspase inhibitors. We found that grim itself shows caspase-dependent proteolytic processing of its C-terminus in vitro. Grim-induced death is antagonized by bcl-2 in a dose-dependent manner, and neither Fas signalling nor p53 are required for grim pro-apoptotic activity. Grim protein localizes both in the cytosol and in the mitochondria of mouse fibroblasts, the latter location becoming predominant as apoptosis progresses. These results show that Drosophila grim induces death in mammalian cells by specifically acting on mitochondrial apoptotic pathways executed by endogenous caspases. These findings advance our knowledge of the mechanism by which grim induces apoptosis and show the conservation through evolution of this crucial programmed cell death pathway.
Clavería
C
C
Departamento de Inmunología y Oncología, Centro Nacional de Biotecnología, Universidad Autónoma de Madrid, 28049 Madrid, Spain.
Albar
J P
JP
Serrano
A
A
Buesa
J M
JM
Barbero
J L
JL
Martínez-A
C
C
Torres
M
M
D016475:3T3 Cells / Q000166:cytology; D000595:Amino Acid Sequence; D000818:Animals; D017209:Apoptosis; D020169:Caspases / Q000378:metabolism; D002451:Cell Compartmentation; D017124:Conserved Sequence; D004330:Drosophila; D029721:Drosophila Proteins; D005455:Fluorescent Antibody Technique; D020287:In Situ Nick-End Labeling; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D018715:Microscopy, Video; D008928:Mitochondria / Q000378:metabolism*; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D011994:Recombinant Proteins; D015398:Signal Transduction; D013045:Species Specificity; D014162:Transfection; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D019014:fas Receptor / Q000378:metabolism
D029721:Drosophila Proteins; D019476:Insect Proteins; D009479:Neuropeptides; D019253:Proto-Oncogene Proteins c-bcl-2; D011994:Recombinant Proteins; D016159:Tumor Suppressor Protein p53; D019014:fas Receptor; C108881:grim protein, Drosophila; D020169:Caspases