tailieunhanh - Báo cáo khoa học: The resident endoplasmic reticulum protein, BAP31, associates with c-actin and myosin B heavy chain Analysis by capillary liquid chromatography microelectrospray tandem MS

BAP31 is a 28-kDa integral membrane protein of the endoplasmic reticulumwhose cytosolicdomaincontains two caspase recognition sites that are preferentially cleaved by initiator caspases,such as caspase-8. Recently,we reported that the caspase-resistant BAP31 inhibited Fas-mediated apoptotic membrane fragmentation and the release of cytochromec from mitochondria in KB epithelial cells (Nguyen M.,Breckenridge G.,Ducret A &Shore G. (2000) Mol. –6740). | Eur. J. Biochem. 270 _4 _2 3- 2003 FEBS 2003 doi The resident endoplasmic reticulum protein BAP31 associates with c-actin and myosin B heavy chain Analysis by capillary liquid chromatography microelectrospray tandem MS Axel Ducret1 Mai Nguyen2 David G. Breckenridge2 and Gordon C. Shore2 1Merck Frosst Center for Therapeutic Research Pointe-Claire-Dorval Quebec Canada department of Biochemistry McIntyre Medical Sciences Building McGill University Montreal Quebec Canada BAP31 is a 28-kDa integral membrane protein of the endoplasmic reticulum whose cytosolic domain contains two caspase recognition sites that are preferentially cleaved by initiator caspases si h as caspase-8. Recently we reported that the caspase-resistant BAP31 inhibited Fas-mediated apoptotic membrane fragmentation and the release of cytochrome c from mitochondria in KB epithelial cells Nguyen M. Bi eckenidlge G. Duceet A Sltore G. 0000 Mol. Cell. Biol. 20 6731 674 i. We describe hei e the chai -acterization by capillary liquid chromatography microelectrospray tandem MS of a BAP31 immunocomplex isolated from a HepG2 usll lysate in the absence of a death signal. We show that BAP31 specifically associates with nonmuscle myosin heavy chain B and nonmuscle c-actin two components of the cytoskeleton actomyosin complex. Collectively these data confirm that BAP31 m add mon to tte poenntial role as a chaperone may payy a Slmdemnnrcl nhe m the structural organization of the cytoplasm. Here we also show that Fas stimulation of apoptosis releases BAP31 associations with these motor proteins a step that may cont li bui re to extranuclear events uuch as membrane l emodeliingt uuring the execution phase of apoptosis. Keywords apoptosis BAP31 mass spectrometry post-translational modifications. Apoptosis or programmed cell death is a physiological mechanism by which multicellular organisms can eliminate in an orderly fashion unwanted or damaged cells during development mescreikm or ss