Down-modulation of a novel Bax-associated protein during apoptosis in normal mature B lymphocytes.
We have recently characterized a novel 16-kDa Bax-associated protein. In this study, we investigate the regulation of this protein's expression during in vitro induction of apoptosis in mature splenic B cells. A panel of biochemically distinct apoptotic stimuli induced the dramatic down-modulation of the 16-kDa protein in B cells; this down-modulation was rapid, and did not require DNA fragmentation. Reciprocally, stimuli that induced protection from apoptosis prevented down-modulation of the 16-kDa protein. These regulatory effects were specific, since Bcl-2 and Bax protein levels were not similarly modulated. Stimuli that reduce expression of the 16-kDa protein may therefore act indirectly to increase the proapoptotic activity of Bax, perhaps by altering Bax binding to other cellular proteins.
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Department of Surgery, University of Pittsburgh School of Medicine, PA 15213, USA.
Hershberger
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PA
McCarthy
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SA
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000276:immunology*; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D002352:Carrier Proteins / Q000096:biosynthesis* / Q000737:chemistry* / Q000276:immunology / Q000502:physiology; D002454:Cell Differentiation / Q000276:immunology; D015536:Down-Regulation / Q000276:immunology*; D005260:Female; D015847:Interleukin-4 / Q000494:pharmacology; D051379:Mice; D008810:Mice, Inbred C57BL; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism* / Q000502:physiology; D013997:Time Factors; D051028:bcl-2-Associated X Protein
C494827:Bax protein, mouse; C113548:Bax-associated protein P16, mouse; D002352:Carrier Proteins; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D051028:bcl-2-Associated X Protein; D015847:Interleukin-4