The proapoptotic BH3-only protein bim is expressed in hematopoietic, epithelial, neuronal, and germ cells.
Proapoptotic Bcl-2 family members activate cell death by neutralizing their anti-apoptotic relatives, which in turn maintain cell viability by regulating the activation of the cell death effectors, the caspases. Bim belongs to a distinct subgroup of proapoptotic proteins that only resemble other Bcl-2 family members within the short BH3 domain. Gene targeting experiments in mice have shown that Bim is essential for the execution of some but not all apoptotic stimuli, for hematopoietic cell homeostasis, and as a barrier against autoimmunity. There are three Bim isoforms, Bim(S), Bim(L), and Bim(EL), which have different proapoptotic potencies due at least in part to differences in interaction with the dynein motor complex. The expression pattern of Bim was investigated by immunohistochemical staining, immunoprecipitation followed by Western blotting, and in situ hybridization. Bim was found in hematopoietic, epithelial, neuronal, and germ cells. Bim(L) and Bim(EL) were coexpressed at similar levels in many cell types, but Bim(S) was not detected. Microscopic examination revealed a punctate pattern of Bim(L) and Bim(EL) immunostaining, indicating association with cytoplasmic structures. These results are discussed in the context of the phenotype of Bim-deficient mice and the post-translational regulation of Bim's pro-apoptotic activity.
Walter and Eliza Hall Institute and the Rotary Bone Marrow Research Laboratories, Royal Melbourne Hospital, Melbourne, Australia.
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O'Reilly
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Cullen
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Visvader
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Lindeman
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Huang
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Strasser
D016475:3T3 Cells; D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; D015153:Blotting, Western; D002319:Cardiovascular System / Q000378:metabolism; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D002490:Central Nervous System / Q000378:metabolism; D004064:Digestive System / Q000378:metabolism; D004703:Endocrine System / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D005260:Female; D005835:Genitalia / Q000378:metabolism; D005854:Germ Cells / Q000166:cytology / Q000378:metabolism*; D006367:HeLa Cells; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007668:Kidney / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D018482:Muscle, Skeletal / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000378:metabolism*; D011518:Proto-Oncogene Proteins; D051381:Rats; D017208:Rats, Wistar; D012137:Respiratory System / Q000378:metabolism; D012867:Skin / Q000378:metabolism; D014018:Tissue Distribution; D014407:Tumor Cells, Cultured
D051017:Apoptosis Regulatory Proteins; C000606775:BCL2L11 protein, human; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; C000606778:Bcl2l11 protein, rat; D002352:Carrier Proteins; D008565:Membrane Proteins; D011518:Proto-Oncogene Proteins