Bcl-2 heterodimerizes in vivo with a conserved homolog, Bax, that accelerates programmed cell death.
Bcl-2 protein is able to repress a number of apoptotic death programs. To investigate the mechanism of Bcl-2's effect, we examined whether Bcl-2 interacted with other proteins. We identified an associated 21 kd protein partner, Bax, that has extensive amino acid homology with Bcl-2, focused within highly conserved domains I ... and II. Bax is encoded by six exons and demonstrates a complex pattern of alternative RNA splicing that predicts a 21 kd membrane (alpha) and two forms of cytosolic protein (beta and gamma). Bax homodimerizes and forms heterodimers with Bcl-2 in vivo. Overexpressed Bax accelerates apoptotic death induced by cytokine deprivation in an IL-3-dependent cell line. Overexpressed Bax also counters the death repressor activity of Bcl-2. These data suggest a model in which the ratio of Bcl-2 to Bax determines survival or death following an apoptotic stimulus.
Mesh Terms:
Amino Acid Sequence, Animals, Apoptosis, Base Sequence, Blotting, Western, Cell Line, Cloning, Molecular, Conserved Sequence, Humans, Macromolecular Substances, Mice, Molecular Sequence Data, Polymerase Chain Reaction, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-bcl-2, Restriction Mapping, Sequence Homology, Amino Acid, bcl-2-Associated X Protein
Amino Acid Sequence, Animals, Apoptosis, Base Sequence, Blotting, Western, Cell Line, Cloning, Molecular, Conserved Sequence, Humans, Macromolecular Substances, Mice, Molecular Sequence Data, Polymerase Chain Reaction, Proto-Oncogene Proteins, Proto-Oncogene Proteins c-bcl-2, Restriction Mapping, Sequence Homology, Amino Acid, bcl-2-Associated X Protein
Cell
Date: Aug. 27, 1993
PubMed ID: 8358790
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