Abstract
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.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Amino Acid Sequence
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Animals
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Animals, Genetically Modified
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Apoptosis Regulatory Proteins
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Blotting, Northern
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COS Cells
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Caenorhabditis elegans Proteins*
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Caspases / metabolism
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Caspases / physiology
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Cell Death / physiology
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DNA, Complementary / chemistry
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DNA, Complementary / genetics
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Drosophila / embryology
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Drosophila / genetics*
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Drosophila / growth & development
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Drosophila Proteins*
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Enzyme Activation
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Eye / embryology
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Eye / growth & development
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Eye / metabolism
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Gene Expression Regulation, Developmental
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Helminth Proteins / genetics
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In Situ Hybridization
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Insect Proteins / genetics*
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Insect Proteins / physiology
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Intracellular Membranes / chemistry
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Membrane Proteins / genetics*
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Membrane Proteins / physiology
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Microscopy, Confocal
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Mitochondria / chemistry
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Molecular Sequence Data
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Phenotype
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Proto-Oncogene Proteins / genetics*
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Proto-Oncogene Proteins / physiology
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Proto-Oncogene Proteins c-bcl-2 / genetics
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RNA, Messenger / genetics
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RNA, Messenger / metabolism
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Sequence Alignment
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Sequence Analysis, DNA
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Sequence Homology, Amino Acid
Substances
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Apoptosis Regulatory Proteins
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Caenorhabditis elegans Proteins
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Ced-9 protein, C elegans
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DNA, Complementary
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Drosophila Proteins
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Helminth Proteins
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Insect Proteins
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Membrane Proteins
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Proto-Oncogene Proteins
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Proto-Oncogene Proteins c-bcl-2
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RNA, Messenger
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debcl protein, Drosophila
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Caspases