Drob-1, a Drosophila member of the Bcl-2/CED-9 family that promotes cell death.
The Bcl-2/CED-9 family of proteins, which includes both antiapoptotic and proapoptotic members, plays key regulating roles in programmed cell death. We report here the identification and characterization of Drob-1, the first Drosophila member of the Bcl-2/CED-9 family to be isolated. Drob-1 contains four conserved Bcl-2 homology domains (BH1, BH2, BH3, and BH4) and a C-terminal hydrophobic domain. Ectopic expression of Drob-1 in the developing Drosophila eye resulted in a rough-eye phenotype. Furthermore, when overexpressed in Drosophila S2 cells, Drob-1 induced apoptosis accompanied by elevated caspase activity. This Drob-1-induced cell death, however, could not be antagonized by baculovirus p35, a broad-spectrum caspase inhibitor. Drob-1 was localized to the intracytoplasmic membranes, predominantly to the mitochondrial membranes, and a mutant Drob-1 lacking the hydrophobic C terminus lost both its mitochondrial localization and its proapoptotic activity. These results suggest that Drob-1 promotes cell death by inducing both caspase-dependent and -independent pathways at the mitochondria. Our identification of Drob-1 and further genetic analysis should provide increased understanding of the universal mechanisms by which the Bcl-2/CED-9 family members and other related proteins regulate apoptosis.
Igaki
T
T
Division of Neuroanatomy, Department of Neuroscience, Biomedical Research Center, Osaka University Graduate School of Medicine, Osaka 565-0871, Japan.
Kanuka
H
H
Inohara
N
N
Sawamoto
K
K
Núñez
G
G
Okano
H
H
Miura
M
M
D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D051017:Apoptosis Regulatory Proteins; D015152:Blotting, Northern; D019556:COS Cells; D029742:Caenorhabditis elegans Proteins; D020169:Caspases / Q000378:metabolism / Q000502:physiology; D016923:Cell Death / Q000502:physiology; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D004330:Drosophila / Q000196:embryology / Q000235:genetics* / Q000254:growth & development; D029721:Drosophila Proteins; D004789:Enzyme Activation; D005123:Eye / Q000196:embryology / Q000254:growth & development / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental; D015801:Helminth Proteins / Q000235:genetics; D017403:In Situ Hybridization; D019476:Insect Proteins / Q000235:genetics* / Q000502:physiology; D007425:Intracellular Membranes / Q000737:chemistry; D008565:Membrane Proteins / Q000235:genetics* / Q000502:physiology; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000737:chemistry; D008969:Molecular Sequence Data; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000502:physiology; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D051017:Apoptosis Regulatory Proteins; D029742:Caenorhabditis elegans Proteins; C087233:Ced-9 protein, C elegans; D018076:DNA, Complementary; D029721:Drosophila Proteins; D015801:Helminth Proteins; D019476:Insect Proteins; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; C404322:debcl protein, Drosophila; D020169:Caspases