title: Loss of the BH3-only protein Bmf impairs B cell homeostasis and accelerates gamma irradiation-induced thymic lymphoma development.
abstract: Members of the Bcl-2 protein family play crucial roles in the maintenance of tissue homeostasis by regulating apoptosis in response to developmental cues or exogenous stress. Proapoptotic BH3-only members of the Bcl-2 family are essential for initiation of cell death, and they function by activating the proapoptotic Bcl-2 family members Bax and/or Bak, either directly or indirectly through binding to prosurvival Bcl-2 family members. Bax and Bak then elicit the downstream events in apoptosis signaling. Mammals have at least eight BH3-only proteins and they are activated in a stimulus-specific, as well as a cell type-specific, manner. We have generated mice lacking the BH3-only protein Bcl-2-modifying factor (Bmf) to investigate its role in cell death signaling. Our studies reveal that Bmf is dispensable for embryonic development and certain forms of stress-induced apoptosis, including loss of cell attachment (anoikis) or UV irradiation. Remarkably, loss of Bmf protected lymphocytes against apoptosis induced by glucocorticoids or histone deacetylase inhibition. Moreover, bmf(-/-) mice develop a B cell-restricted lymphadenopathy caused by the abnormal resistance of these cells to a range of apoptotic stimuli. Finally, Bmf-deficiency accelerated the development of gamma irradiation-induced thymic lymphomas. Our results demonstrate that Bmf plays a critical role in apoptosis signaling and can function as a tumor suppressor.
authors.affiliation: Division of Developmental Immunology, Biocenter, Innsbruck Medical University, 6020 Innsbruck, Austria.
authors.forename: Verena
authors.initials: V
authors.lastname: Labi
authors.forename: Miriam
authors.initials: M
authors.lastname: Erlacher
authors.forename: Stephan
authors.initials: S
authors.lastname: Kiessling
authors.forename: Claudia
authors.initials: C
authors.lastname: Manzl
authors.forename: Anna
authors.initials: A
authors.lastname: Frenzel
authors.forename: Lorraine
authors.initials: L
authors.lastname: O'Reilly
authors.forename: Andreas
authors.initials: A
authors.lastname: Strasser
authors.forename: Andreas
authors.initials: A
authors.lastname: Villunger
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000172:deficiency* / Q000235:genetics; D000818:Animals; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000172:deficiency / Q000235:genetics; D001402:B-Lymphocytes / Q000166:cytology / Q000378:metabolism*; D000072224:Bcl-2-Like Protein 11; D005720:Gamma Rays / Q000009:adverse effects; D006706:Homeostasis; D008223:Lymphoma / Q000209:etiology*; D008565:Membrane Proteins / Q000172:deficiency / Q000235:genetics; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D011518:Proto-Oncogene Proteins / Q000172:deficiency / Q000235:genetics; D015398:Signal Transduction; D013953:Thymus Neoplasms / Q000209:etiology*; D025521:Tumor Suppressor Proteins / Q000172:deficiency / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D000072224:Bcl-2-Like Protein 11; C000606776:Bcl2l11 protein, mouse; C435486:Bmf protein, mouse; D008565:Membrane Proteins; C488588:PUMA protein, mouse; D011518:Proto-Oncogene Proteins; D025521:Tumor Suppressor Proteins